• Abstract of Papers Presented
• Abstract of Posters Presented

ABSTRACTS OF PAPERS PRESENTED AT 45TH ISAM CONFERENCE 17-19 NOV 2004

High-G training in closed loop- Our Initial Experience
Wg Cdr PK Tyagi, Wg Cdr A Sinha

A pilot-in-loop mode has recently been added thus making the centrifuge a closed loop system with pilot controlling the G-force from inside the gondola. This has brought about a sea change in the centrifuge training being conducted at IAM as the training for 13 long years ( from March 1991 to March 2004) was in open loop where the pilot was a passive rider. The high-G training at IAM has been restructured to accommodate closed loop runs. The G-tolerance time of fighter pilots have gone up significantly as the latter are able to ride the G-forces with greater confidence and full control while performing a tracking task administered through a LCD display in the gondola. The subjective feedback from pilots is positive. The paper discusses the results of our experience with high- G training in the closed loop human centrifuge and the feedback obtained from the pilots.

Repetitive +Gz Exposure and Improved Cardiovascular Performance: Implications for +Gz Tolerance
Dr. David G. Newman

The high +Gz environment is characterised by frequent, short-duration, high intensity +Gz excursions, particularly when the pilot is engaged in air combat manoeuvring. These multiple high +Gz events lead to repetitive activation of the arterial baroreflex mechanisms, in order to preserve adequate levels of cerebral perfusion and protect against G-induced loss of consciousness. Fighter pilots report that their tolerance to the high +Gz environment increases with regular exposure. Objective evidence of cardiovascular adaptation to altered gravitational states has been extensively investigated in terms of the human experience of microgravity and spaceflight. Increasing attention is now being paid to the development of functional changes in physiological systems as a result of repetitive exposure to the high +Gz environment. This paper will review the emerging body of physiological evidence that pilots of high performance fighter aircraft develop a degree of cardiovascular adaptation to the high +Gz environment in which they operate. These findings provide a physiological basis to the anecdotal experience of fighter pilots that they adapt with regular and repetitive occupational exposure to high +Gz loads. The implications for +Gz tolerance and +Gz training will also be discussed.

Helicopter Crew Conditioning Programme
Wg Cdr G Gomez, Sqn Ldr M Mukerji

Backache is a significant problem in rotary wing aircrew and is mainly attributed to the poor sitting posture the pilots need to adopt to operate the cyclic and collective controls. Other contributory factors include vibration and poor workspace design. The general approach to this malady has been the use of lumbar support, new seat designs and improved cockpit ergonomics in terms of better controls. However, so far no such permanent measure have been implemented in rotary wing aircraft of the IAF, Indian Navy and Army Aviation Corp. At best, some stop gap measures have been resorted to locally. The role of back exercises in maintaining functional ability and for the therapy of backache has been well established. With this premise a new approach has been resorted to, in that a physical conditioning program specifically targeting the back muscles has been devised for rotary wing aircrew. This paper discusses the course design and conduct of the first ever physical conditioning program for helicopter pilots in the IAF. A 04 week helicopter aircrew conditioning program was conducted on this forward flying base of the IAF. The course was specifically designed to target the back musculature. In all 23 helicopter pilots participated. Post course an anonymous questionnaire was applied on all participants, soliciting their unbiased views on a range of issues such as the problem of backache and its alleviation, the course content and suggestions for improvement. This paper discusses the findings of this survey and makes suitable recommendations for possible implementation in the IAF.

Use of Digital Anthropometric Mannequins for Human Engineering Evaluation: Rear Work Station : ALH (NAVY)
Surg Cdr LJ Pinto, Wg Cdr N Taneja

Digital 3 dimensional human mannequins are in use worldwide in Computer Aided Design of workstations, but till now suitable anthropometric mannequins with dimensions close to Indian Pilot Population were not available. The Naval version of the Advanced Light Helicopter (ALH) has two crew workstations located in the aft fuselage. These workstations are designed to allow two Naval Observers to track surface targets by radar and underwater targets through dunking sonar as well as disposable sonobouys. The workstations were required to be ergonomically evaluated. Digital anthropometric mannequins corresponding to Indian Pilot population were used along with Auto CAD drawings of the rear fuselage of the aircraft to study the workspace. Thereafter, the stations were physically evaluated with selected subjects. This paper discusses the development and use of digital anthropometric mannequins for ergonomic studies in airborne platforms.

UAV Operations: An Analysis of Incidents and Accidents with Human Factors and Crew Resource Management Perspective
Wg Cdr Sanjiv Sharma, Fg Offr D Chakravarti

Background: There is evidently no Human Factors (HF) analysis during Court of Inquiry (COI) in various incidents and accidents (I & A) in Unmanned Aerial Vehicle (UAV) operations in India. Hence, human error as a causative or a contributory factor in the outcome of a situation leading to an accident was not commented upon. With this background, human factors (HF), especially crew resource management (CRM) issues in effective UAV operations are analysed with an aim to prevent similar accidents in future. Methods: A critical retrospective analysis of COI in UAV I & A was undertaken. In the absence of a HF Specialist in UAV related COI, there were no records of detailed analysis of HF. Hence the HF were gleaned through from the available material. Results: Between the years 2000 to 2004, there were several incidents and accidents in UAV operations. In most of the COI all the accidents pointed at human error (HE) of operators, either as a contributory factor or direct cause. Discussion: The COI were analysed to find a pattern of HE committed by the operators. Role of HF, especially CRM issues, in safe UAV operations and the future trends in UAV operations and related safety issues are discussed. Recommendation: It is recommended that CRM training programme be conducted for UAV operators for effective mission accomplishment with safe operations. It is also recommended that a HF Specialist be involved in investigation of future UAV accidents, to bring out relevant HF issues and suggest remedial measures.

Analysis of Post Ejection Spinal Injuries Vis-A-Vis Use of Naz 7 and Naz 7M Survival Packs
Wg Cdr P Pant, Gp Capt H Malik, Wg Cdr D Gaur

Modern fighter aircraft are fitted with ejection seats so that during an in-flight emergency, the pilot can initiate timely ejection. Ejection seats also have a survival pack that is kept under the seat pan. Spinal injury is considered as one of the most serious injury encountered at the time of ejection, as many a times it may be life threatening. Relevant court of inquiry details of Cat I accidents of MiG variants in the last seven years were referred and information pertaining to spinal injury patterns post ejection was obtained. Special emphasis was given to identify the type of survival pack fitted in the aircraft, which had ejections. This was done to establish the fact whether modified version of NAZ 7 type of survival pack, which is fitted in place of NAZ 7 in few MiG variants contributed to an increase in spinal injuries. A total of 90 aircraft were involved in 87 Cat I accidents. MiG 21 Bis had maximum number of Cat I accidents, amounting to 33 (36.67%)ollowed by MiG 27 ML with 16 (17.78%) accidents. Out of a total of 35 ejections where NAZ 7 survival pack was fitted in the ejection seat, only 9 (25.71%) sustained spinal injuries, whereas only 7 (38.88%) sustained spinal injuries out of 18 ejection cases fitted with NAZ 7M survival pack. Statistically it was established that there is no difference between the spinal injury patterns vis-a-vis use of NAZ 7 or NAZ 7M survival pack. However, the most important factor that contributed to spinal injury in the aircrew appeared to be maintenance of incorrect posture at the time of ejection.

A3 to A1 at the Field: Applying an Economic Model to Evaluation of Aircrew with Musculoskeletal Disabilities
Wg Cdr Narinder Taneja, Surg Cdr LJ Pinto

IAM, IAF is the nodal centralized agency responsible for review and evaluation of aircrew with musculoskeletal disabilities in the armed forces. Such centralization has been designed with many objectives in mind. These include standardization of evaluation, availability of expertise and avoidance of any local pressures. These are essential to ensure safety of both the aircrew as well as the machine they fly. At IAM when an aircrew has reached clinical and radiological finality, he is evaluated Department of Human Engineering with the aim of returning him to flying duties. An extensive evaluation of his functional abilities involving the use of various mechanical devices is carried out to ensure that he is safe to be returned to the cockpit. He is then subjected to relevant simulated aviation stresses such as vibration and acceleration stress. A composite assessment then enables the medical board to upgrade the aircrew to a restricted flying category of A3 for a minimum of 12 weeks.The individual is recommended to report back for review with an executive report on flying. The board specifies the areas that should be commented upon in the executive report. Review at IAM till this stage ensures that all the objectives of centralized evaluation are met with. The aircrew is evaluated at IAM after 12 weeks with an executive report on an average of 2-3 sorties. With a complementary executive report, he is usually placed in a permanent flying category (A1/A2). It is important to emphasis that during this review he is not subjected to repeat radiology, vibration or centrifuge stresses. The author argues that aircrew with musculoskeletal disabilities (to start with) can be reviewed and upgraded from A3 to A1 or A2 at the field level. Such a process will still be able to achieve all the objectives as enumerated above as the aircrew was returned to flying duties after being extensively evaluated at IAM. This proposed change in review process could result in a saving of 50- 60 days for each aircrew. An economic cost model is applied to this evaluation process. The financial savings to the exchequer can be enormous and the theoretical implications; of such savings are discussed. The pros and cons of such as revised proposal are elaborated. The proposal is supported with data collected and analyzed at the Department of Human Engineering.

Suggested Operating Schedules for Sudden Induction of Unacclimatised or Partially Acclimatised Aircrew for Air Operations at High Altitude
Gp Capt Pankaj Tyagi, Gp Capt H Malik

Indian Air Force is first air force in the world, to have all types of sustained air operations for long period, from high altitude air airfields and helipads. Existing instructions on "Effects of cold and high altitude and their prevention" do not cater for fighter, transport, helicopter aircrew and supporting airmen aircrew operating in and out of high altitude airfields. A prudent policy with clear-cut directives is required to seize the issues involving the safety of the unacclimatized aircrew, required to operate at high altitudes for operational reasons. The situations which require solution are sudden induction of Fighter, Transport, Helicopter aircrew to high altitude on detachment, Transit aircrew that arrive at high altitude for a short period of time, Transit aircrews that are forced to stay at high altitude for more than normal required period, Aircrew permanently based at high altitude and Personnel on detachment to high altitude. An analysis of the statistics of HAPO cases in Armed forces to decide the maximum safe period that an unacclimatized individual can spend at high altitude, on being inducted by air was conducted at Western Air Command. Cases were taken from HMRC Leh and from the database at AFMC Pune to ascertain the minimum period in hours but it is confirmed that unsatisfactory acclimatization induces HAPO even on the first day of induction. The recommended Operating Schedules for sudden induction of unacclimatized or partially acclimatized aircrew and the basis of recommending the schedules to IAF have been discussed in this paper.

Temporal Adjustments in Working Memory and Vigilance Functions During 6 Days of Acclimatisation at 10,500' Altitude
Lt Col KK Tripathi, Lt Col CV Apte, Dr CR Mukundan

Background & Objectives- Operational exigencies, sometimes, do not permit aviators to acclimatise, adequately for 6 days as recommended at an operating altitude of 10,500'. This study was conducted to examine the adequacy of a short acclimatisation (of 36 hours) in terms of certain cognitive attributes viz, working memory and vigilance functions. Methods- A cross section of 197 subjects was examined during the period of acclimatisation for 6 days after induction by air. Out of these, 20 subjects were also followed, longitudinally. To factor out effects of familiarity and practice, 20 'controls' were examined at the ground level for a similar duration. All the subjects were low landers. Results- In the cross sectional group of subjects, performance in both working memory and vigilance tasks did not vary across the period of acclimatisation. Response accuracy and reaction time were essentially comparable after 36 hours and 6 days of induction (p>0.05; Kruskal-Wallis ANOVA). In the subjects followed longitudinally, a consistent improvement was noticeable from 2nd to 3rd day, onwards (p<0.05; Friedman ANOVA). However, this improvement was comparable to that observed in the 'controls' (p>0.05; Wilcoxon Matched Pairs Test). 8-10% of the subjects exhibited AMS Scores>4 on Lake Louise protocol between 2nd to 4th day after induction. However, we did not find any correlation between AMS Scores and performance in the above tasks (P>0.05; Spearman Rank Order Correlation). Conclusion- The study notices comparable performance in working memory and vigilance tasks after 36 hours and 6 days of induction to 10,500'.

Altitude Chamber Training for Aircrew: A Questionnaire Feedback Survey
Wg Cdr VV Joshi, Wg Cdr CS Thakur

Introduction: We took up the present questionnaire survey to assess the views of the aircrew about altitude chamber training, with the aims of assessing the training efficacy and increasing the operational significance of this training. This paper presents the findings of this survey and its impact on fine-tuning the chamber training. Material & Methods: A questionnaire, consisting of qualitative and quantitative questions; divided into 5 subsections, was designed. The questionnaire was dispatched to 142 aircrew that had completed the altitude chamber -training capsule at 1 AMTC in the period Jan 2002-Dec 2003, by snail mail. The questionnaires were sent 2 to 6 months after the completion of the training capsule. Returned completed questionnaires were divided into aircrew of fighter, helicopter and transport stream and analyzed qualitatively and statistically. Results: 74 completed questionnaires were received back. (Return rate=52.1%) There were no statistically significant differences in the responses given by fighter, helicopter and transport aircrew except between the helicopter aircrew and transport aircrew in their appreciation of pulse Oximetry as a training tool. 77% and 72.6% of aircrew did not develop any symptoms in the hypoxia demonstration and Ear Clearance Demo respectively. Commonest symptoms that were reported in Hypoxia Demo were hyperventilation followed by difficulty in mental concentration. Majority of aircrew (83.3%) indicated preference to have hypoxia demo at 25000 ft and lesser altitude. The aircrew reported average 24.1% addition to their knowledge of Otitic Barotrauma after chamber training. Majority of the aircrew appreciated the physical, physiological and operational aspects of rapid decompression during the training demo. The average overall usefulness of Altitude Chamber training, marked on a scale of 1 to 10, was 7.6 (maximum to transport aircrew = 8.1). 73% aircrew reported that the training helped them in planning high altitude sorties. Conclusions: The feedback on altitude chamber training from the aircrew is satisfactory. However, it brings out that further fine-tuning, primarily in the areas of realism and operational relevance, needs to be attempted. Responses given by the three streams of aircrew indicate that chamber training needs to be more stream-specific and aircraft specific. Low incidence of symptoms in hypoxia demonstration emphasize the need to standardize the non-symptom based, qualitative hypoxia recognition during training.

Accidents in the IAF: Analysis of Perceived and Actual Causes
Wg Cdr A Agarwal

The accident rate of the IAF has been steady at approximately 1.00 ± 0.225 (mean ± SD) per 10,000 flying hours, for the past 20 years. Concerted effort by the directorate of flight safety in the past decade has failed to reduce this. The accident rate in the past five years (1998-2003) remains at 0.96 ± 0.129 per 10,000 flying hours. This study was aimed at studying what aviators perceive as causes of accidents versus the actual causes found in Courts of Inquiry (CsOI). Methodology: Perceived causes of accidents were determined using a questionnaire. The questionnaire was prepared with the help of the ten most experienced aviators in the station with a combined experience of 33846 hrs of military flying. This was then validated by a separate board consisting of five aviators. Finally intra-test and test-retest reliability were tested, to determine the reliability of the questionnaire. Results: The test had a good intra-test and test-retest reliability with coefficients of 0.77 and 0.92 respectively. Aviators perceived poor training for flying in bad weather, lack of simulators, 'fire-fighting' for flight safety, poor planning by higher formations as the most important causes of accidents. 20 CsOI studied failed to give any consistent results for the cause of accidents. The same CsOI when re-analyzed, indicated poor 'fire-fighting' for flight safety, poor planning by higher formations and violations as the most important causes of accidents. The implications of these results have been discussed, and a strategy for better understanding of accidents has been suggested.

A Study of Disease Pattern Amongst Cabin Crew of Indian Airlines,Western Region, Mumbai
Dr. Ashish Bhagat, Dr. Vikram Simha

Cabin crew of Indian Airlines who are above the age of 35 yrs were taken for an annual medical check-up since 1998 onwards. We have studied the pattern of diseases amongst the cabin crew of Western Region for the last 4 years. A total of 230 crew comprising of 209 Airhostesses & 21 Flight Stewards were screened for any systemic disorder. The female to male ratio was 9.9:1.In this study, the predominant illnesses detected were Systemic Hypertension in 13.2%, Spondylosis (Cervical & Lumbar) in 9.4%, Anemia in 7.1%, Thyroid disorders in 6.1%, Dyslipidemia in 3%, Tuberculosis in 3%, Diabetes Mellitus in 2.8%, Cholelithiasis in 2.3%. Other disorders detected in small numbers were Rheumatic Heart Diseases, CAD, Migraine, Renal calculi, Dorsal Scoliosis &Carpal Tunnel Syndrome. Among female patients Ovarian Cysts were detected in 1.2%, Uterine Fibroids in 3.5% & Fibroadenoma breast in 1.6%. 2 cases of Sarcoidosis were also detected. Minor short duration ailments i.e. URTI,UTI, Short Duration Fever, Amoebiasis etc. have been excluded in this study. In this study we observed amongst the cabin crew a male preponderance in systemic hypertension & Coronary Artery Disease, whereas, Thyroid disorder, Anemia, Spondylosis (Cervical & Lumbar), Diabetes Mellitus & Carpal Tunnel Syndrome were predominant amongst females..

Polymorphic Light Eruptions in Ground Crew
Wg Cdr PS Murthy, Wg Cdr S Grover, Lt Col PK Kar

Polymorphous light eruption (PMLE) is an acquired, idiopathic photodermatosis. It is characterized by recurrent, abnormal, delayed reactions to sunlight, ranging from erythematous papules, papulo-vesicles, and plaques on sunlight-exposed surfaces. Commonly the neck and the forearms are involved. It tends to heal without scarring, but with pigmentation.Ground Crew of the Indian Air Force work for long hours on the tarmac under hot sun through-out the year, therefore are at increased risk of developing PMLE. It is a common cause of dermatological referral to the Armed Forces hospitals.During the year 2001 to 2002, 110 (45 male and 65 female) new cases of PMLE were diagnosed at Command Hospital Air Force Bangalore. Among these 45 male patients, 19 were Ground crew. Duration of symptoms prior to diagnosis ranged from 1 to 7 years. Lesions were predominantly papules, followed by plaques and vesicles. They were distributed mostly on the forearms, neck and face. Biopsy done in 7 cases showed a lymphocytic perivascular infiltrate. Lesions resolved in 4.58 days after therapy with topical corticosteroids and sun protection. Recurrence rate were high, mainly because patients did not follow correct sun protection measures. Symptoms resolved without recurrence for 1 year in only 24% of patients. The paper highlights the incidence, recognition, treatment and prevention of polymorphic light eruption in the highly susceptible population of Ground Crew who are occupationally exposed to long hours of sunlight. The paper is of relevance to Squadron Medical Officers of Indian Air Force.

Carriage of MEDA Passengers on Jet Airways- A Retrospective Study
Dr. BM Pathan

We retrospectively studied the number of MEDA cases traveling by Jet Airways during the one year period from 1st April 2003 to 31st March 2004. During this period the total number of MEDA forms processed / sick passengers evaluated, was 733, of which 79 % were allowed to fly. Of the total number of passengers carried, 9% had CNS problems, 13% had Respiratory System problems, 20% had CVS problems, 11% had malignancies, while others fell in the Miscellaneous Group.In flight complications were encountered in about 7% of the cases, details of which will be given during the presentation.

Aeromedical Decision Making in Civil Aviation A Review of Cases from 2001 to 2004
Wg Cdr Deepak Gaur, Gp Capt Harish Malik

On scrutiny of medical records of civil flight crew at DGCA certain records are put up to the Senior Adviser (Av Med) at Air HQ, prior to approval. These include all cases of permanent unfitness of flight crew, cases of flight crew appeals against decision of Aero medical Examiners( AMEs) or Aero medical Centre (AMCs) and cases where the medical assessor at DGCA disagrees with the opinion of AMEs /AMCs. On a case-to-case basis such records may be put up to PDMS(S) and DGMS (Air) at Air HQ as deemed necessary. During the period Jan 2001 till date, 79 such cases were brought to Air HQ from DGCA. These belonged to 69 flight crew. Of these, 36 were put up for confirmation of awarded permanent medical unfitness. In 11 cases the medical assessor disagreed with opinion of the AMEs/ AMCs and these were put up for amendment of fitness/ unfitness of limitation status. 22 cases were granted fitness (with or without limitation) on review. 8 were re-confirmed as unfit on review and in 3 cases the appeals were rejected for lack of supporting medical evidence. A system-wise breakdown of the cases revealed that 58 cases were for medical/ surgical conditions, among which the leading contributors were 14 cases of Coronary Artery Disease, 11 cases of EEG abnormality, 8 cases of Diabetes Mellitus/IGT/IFG and 3 cases each of major psychiatric disorders and Essential Hypertension. Among ophthalmologic cases there were 3 cases of substandard colour perception and 2 cases each of high myopia and Squint. Perusal of these cases reveals interested trends and repetitions. The paper discusses the need for better dissemination of medical policies to Class II AMEs. The requirement of EEG for initial issue Class I medical examinations is reviewed. Standardization of medical assessment at various AMCs is re-emphasized.

Managing Pilot Fatigue in Sustained Military Operations I: Applied Research on Alertness-Enhancing Pharmaceutical Compounds
Dr. John A. Caldwell

Introduction: Over the past 50 years, technology has rapidly evolved to produce aircraft and equipment capable of the ultra-long-range flights and continuous, non-stop, day-night operations that are common in today's battlespace. Unfortunately, in this same timeframe mankind has changed very little, and this has created a mismatch between operational demands and the human's basic biological capacity. Although aircraft can operate around the clock with little or no downtime, pilots must take periodic respite for sleep in order to sustain alertness and performance. When such sleep opportunities are limited or nonexistent, pharmacological strategies such as caffeine, dextroamphetamine or modafinil offer the only realistic hope for temporarily countering the deleterious effects of pilot fatigue. Methods: Since caffeine is a freely-available, non-prescription substance already in use throughout both civil and military aviation, little controlled aviation- relevant research has been required with caffeine. However, prescription compounds must meet rigorous objective criteria prior to their introduction into the cockpit. The present paper details a series of objective placebo- controlled studies designed to ensure that both dextroamphetamine and modafinil are safe and effective for use in military aviation sustained operations. Results: Three separate investigations with dextroamphetamine (in a flight simulator and in a specially instrumented aircraft) have shown that this compound sustains the objectively-measured flight performance and alertness of sleep-deprived pilots for over 35 continuous hours. A fourth simulator study indicated that dextroamphetamine also was effective for over 55 continuous hours of wakefulness. Two separate investigations with the newer compound modafinil have demonstrated the safety and efficacy of this compound for over 35 continuous hours without sleep, although side effects occurred with the higher dose. A third study is presently underway to investigate modafinil's effects in a specially-instrumented aircraft. Conclusion: Fatigue from sleep deprivation severely compromises the performance and alertness of even the best-trained pilots; however, properly administered dextroamphetamine or modafinil can safely and effectively extend operational readiness on a temporary basis (i.e., for 35-55 continuous hours of wakefulness).

Managing Pilot Fatigue in Sustained Military Operations II: Applied Research on Sleep- Enhancing Pharmaceutical Compounds
Dr. J Lynn Caldwell

Introduction: Rapid time- zone transitions and unpredictable work hours are common features of the modern military aviation environment. In order to support today's high operational tempos, pilots and crews often are required to work non-standard schedules which require them to work and sleep at times that are contrary to their internal biological clocks. As a result, circadian disruptions (often referred to as jet-lag and shift-lag) threaten to degrade alertness and performance in flight operations. One part of the problem is that crews are working at the "drowsy times of day" during which they are striving to over come their biological propensity for sleep. Another part of the problem is that crews are suffering from the pre- duty sleep deprivation arising from their attempts to sleep during times when they are biologically programmed to be awake. Since chronic sleep restriction has been identified as a major cause of on-the-job fatigue, countermeasures designed to optimize available sleep opportunities are essential to subsequent mission safety and effectiveness. Methods: The sleep-promoting compounds temazepam and zolpidem are particularly suitable for use in aviation-related military contests. The present paper details the results of a subject of objective, placebo-controlled studies designed to quantify the utility of these drugs for inclusion in an overall program of aviator fatigue management. In addition, information will be provided regarding the potential usefulness of two newer sleep-promoting compounds for aviation contexts. Results: The first investigation established the usefulness of zolpidem for sustaining sleep-deprived pilots via the induction of a 2-hour rest period and a placebo nap in terms of objectively-measured arousal, subjective sleepiness, and performance on an aviation-based task. The second investigation established the utility of temazepam for improving the nighttime alertness of pilots by optimizing prior daytime sleep. Results showed that temazepam enhanced sleep quality to normal levels, and by so doing, mitigated decrements in the nighttime performance and alertness of pilots on rotating shifts. A third and fourth study are under development 1) to evaluate the benefits of promoting early-onset sleep in pilots reporting for an early- morning departure, and 2) to assess the possibility of maximizing recovery sleep by pharmacologically enhancing its slow-wave content. Discussion: Fatigue from chronically-restricted sleep and circadian to overcome on-the-job fatigue by optimizing available sleep opportunities, particularly those that occur at non-sleep-conducive times.

CAT-1 Fatal Fighter Aircraft Accident: A Case Report
Sqn Ldr D Talukdar

A Mig-27 U/T pilot took off from Hasimara for a solo practice diversion sortie over Bagdogra base. An average assessed pilot with 345 hrs of total flying, 139 hrs as solo and 206 hrs as dual. Weather was unrated over both the bases during takeoff. The sortie was planned as climbing to 3.0 km, turning towards Bagdogra airfield for a circuit approach and over-shoots followed by climbing back to 3.5 km and set course to base. Overhead Bagdogra, he carried out a turn through approx 150º for heading toward base. The SRE had lost pick up at about 10 Km (5 Nm) from overhead when last call received was "3.5 km setting course to base". The aircraft is missing since then. The terrain is generally flat with hills towards north of both bases. The weather on that day was one typical of monsoon in the NE with rapid building up of clouds. Accident site was located after 15 days amidst dense reserve forest 8-9 km from Bagdogra. Crash site revealed vertical nose down impact with aircraft parts and pieces of flying clothing along with few bone pieces scattered up to a radius of 130 meters. The ejection sequence was not initiated. Analysis reveals aircraft fully serviceable before the sortie and prior to impact. Possible entry into cloud, less experience on IF sorties, failure to call on RT and 900 banks with vertical impact, spatial disorientation was considered most probable cause of the accident.

Human Factor Accidents: Despite Reason When Will We Realise? A Case Report
Wg Cdr Sajan Sethi

Two pilots, an experienced instructor and a trainee, were authorised to fly a Tail Chase Dual sortie in a MiG - 21(T-69) with another experienced pilot as the formation leader. The pilots attended the met briefing at 0600 hrs. The weather reported was visibility 3 km haze, 2AC 10,000 feet and 1 Ci 25,000 feet. At 0655 hrs formation leader got airborne for a pick up orbit and reported a thin layer of clouds at 300-400 m indicated and visibility 'in excess of 4 km'. At 0657 hrs, the trainer got airborne. After an uneventful exercise, the formation reported over the airfield. Formation leader turned for GCA and the trainer descended for a visual circuit. On down wind the trainer captain reported low clouds at a height of 250 m indicated. Subsequently, R/T contact with them was lost and the aircraft was found to have crashed into a small hillock located approximately 7.2 Km from the runway, on approach path. Both pilots had sustained fatal injuries on initial impact. Assessment of the accident revealed a number of failed defences, errors and unsafe acts, at various levels of control, which culminated in the accident. These include the failures at the administrative levels, with the support services and finally by the aircrew themselves. Despite being aware of the "human factors" involved in the causation of aircraft accidents, the emphasis on human error by aircrew [HE (A)] and human error maintenance [HE (M)] we inadvertently overlook a very important factor, the human errors by the administration. The recurrence of these factors and lack of attention to the same, at the operational bases and accident investigation courts is a cause for concern. The same with human factors in other accidents is highlighted in this paper.

Fatigue in Helicopter Flying During Flood Relief Operations: A Case Report
Wg Cdr D Chakraborty

A MI- 8 helicopter unit flew a total of 235 sorties in 218:30 hrs dropping 268.665 tonnes of relief material and carrying a total of 554 passengers, during flood relief operation in a recent devastating flood, which affected Bihar. This included an average of 53 hrs of flying by 7 aircrew who flew as pilot / copilot. The capabilities of both man and machine were tested to extreme limits. An accident in one MI-8 helicopter indicates that aircrew gets fatigued due to nature and duration of sortie. SOP's are to be adhered to and provision should be made for adequate rest for aircrew if accidents are to be prevented.

Motivational Work Needs and Personality Factors in Aircrew
Dr Catherine S George, Dr Biju Thomas, Mrs CG Roopa

Motivational work needs and personality both have a direct bearing on the high stress occupational role of aircrew and are attributes which are of prime importance in selection, training and evaluation. The aim of this study was to (i) investigate the general order of priority that aircrew assign to the motivational work needs of achievement (n ach), affiliation (n aff) and power (n power) and (ii) delineate whether motivational work needs are associated with any personality factors. Fifty five aircrew were administered both the 16 PF test and the Work Needs Assessment Inventory, as a part of their clinical evaluation. Test results were scored and the number of aircrew who had n ach, n aff and n power needs in order of priority were calculated and subjected to chi square test. The three work needs and twenty personality variables' scores were then analysed both within and between each other using Pearson's product moment correlation. Results indicated that a significant majority of aircrew assigned n ach, and n aff work needs almost equally in the first and second positions and placed n power in the third position. Also, n ach, and n aff were negatively correlated with each other and with n power. N ach, and n power showed no significant relationship with personality factors. Only n aff was positively correlated with Factor N (Shrewdness), the second order factors of AP (Alert Poise) and I (Independence), and negatively correlated with Factor A (Warmth). These characteristics appear to be distinct and therefore need to be measured independently when addressing issues related to selection, training and evaluation of aircrew.

Peace Time Transformation of the USAF Aeromedical Evacuation System
Col David G Schall, USAF

Introduction: Multiple changes have occurred in the USAF aeromedical evacuation (AE) system designed to increase trauma intervention and patient movement support capability to USAF expeditionary operations. From a change in Concept of Operations (CONOPS) to new equipment and a mix of mobility assets and commercial options, the USAF aeromedical evacuation system is adapting to new circumstances and improving capability. Aim: To provide an overview of the new USAF AE CONOPS integrating patient movement into joint multimodal options which optimize the use of organic military and commercial travel assets including civilian air ambulance. Methods: A multidisciplinary working group met in 1999 to completely overhaul the USAF AE system. A whitepaper provided the background for transition to a capability-based system without dedicated airframes. Subsequently, the draw down of mobility airframes and the withdrawal from operations of the C-9A aircraft fleet accelerated implementation timelines in the Pacific region. The CONOPS became effective in May 2003. To support peacetime, the AE system aligned with operational airlift processes and routes and focused on validated patients requiring inflight care. Results: Acquisition of patient support pallets (PSP) and patient loading systems provides little capability on the KC-135 and other passenger-capable airframes in order to expand patient movement capability globally. Additionally, implementation of a standardized Critical Care Medical Attendant Team (CCMAT) concept is being implemented in Pacific Air Forces and new technologies such as the Life Support for Trauma and Transport (LSTAT) System are currently in the process of being fielded. Conclusion: The USAF aeromedical evacuation system is in the midst of the most profound transformation in 50 years. The anticipated result will be a more robust, agile and adaptive system that enhances ability to rapidly move patients to appropriate medical treatment, and will be well suited to the expeditionary needs of the 21st century Air Force.

Exercise Cope India 04: A Model for Collaborative Medical Training
Maj Timothy A McGraw, USAF, Wg Cdr J Singh, Sqn Ldr MS Nataraja

Introduction The Indian Air Force and US Air Force conducted the second COPE INDIA exercise at Gwalior Air Force Station from February 16-26, 2004.COPE INDIA 04 was designed to strengthen and broaden bonds between the USAF and IAF, and enable participants of both air forces to sharpen air combat skills through "Dissimilar Air Combat Training" (DACT), improve procedures for sustained operations, as well as promote closer relations and enhance interoperability. A medical component to this exercise had previously been approved at the USAF/IAF Executive Steering Group as a formal way ahead to enhance medical interoperability between the two air forces. Aim This presentation will examine the bilateral medical activities conducted during COPE INDIA 04, discuss the relative benefits derived by each of the respective air forces, and review the lessons learned. Methods IAF and USAF medical personnel planned and executed an aircraft accident response exercise, a firefighter aircrew extraction exercise, and a joint Search and Rescue (SAR) exercise. Ongoing clinical and aeromedical information exchanges were conducted on a daily basis and included such topics as sleep hygiene, circadian rhythm disturbances, pharmaceutical /non-pharmaceutical means to promote alertness and sleep, in-flight hydration, nutrition and elimination. Results Advanced planning and coordination resulted in an extremely successful outcome for this exercise. Both USAF and IAF medical personnel benefited from training and in turn, shared experience and knowledge with counterparts. Conclusion Exercise COPE INDIA 04 represented an important step in improving interoperability between the USAF and IAF and enhancing aeromedical support to flying operations. Advanced planning significantly impacted medical training conducted during this exercise, setting COPE INDIA 04 as a model for future exercises to follow.

Evaluation of Efficacy of the Sleep Inducing Drug in Aircrew Flying Jaguar Aircraft: A Field Trial
Sqn Ldr MS Nataraja, Wg Cdr D Gaur, Gp Capt H Malik, Air Cmde SP Kapoor

The Jaguar aircraft of IAF took part in the just concluded multilateral exercise Co-operative Cope Thunder conducted at Alaska, USA. Ferrying of these fighter jets for the exercise included multiple legs of long duration flying across a number of time zones. It is a well known fact that long duration flying across time zones are liable to affect the bio-rhythms of the aircrew resulting in early fatigue and decrement in the performance. Air forces of some of the advanced countries use medication in the form of "Go-pill" and 'No go-pill" to reduce fatigue and maintain performance. A trial was conducted to evaluate the efficacy of a sleep-inducing drug Zolpidem (Zleep), as an anti-fatigue medication. 15 Jaguar aircrew took part in the study conducted at one of the training bases of IAF. The trial was conducted in two phases: the first phase, consisted of 'pre-test' on ground and a second phase wherein the residual effect of the drug on flying was evaluated. The response of aircrew to the medication was analyzed through a questionnaire survey. The study indicated that Zolpidem could be used effectively as a sleep inducing medication in fighter aircrew as an anti-fatigue medication.

Aeromedical Aspects of Long Duration Ferries Ex-Golden Eagle
Wg Cdr D Malik

Six Mirage 2000s of IAF participated in Ex-Golden Eagle at South Africa recently. Due to certain operational compulsions the IAF decided to ferry the Mirages over the Indian Ocean doing Air - To - Air Refueling (AAR) from the IL-78 Tankers. The team went about this aspect in a very methodical manner for preparing, planning and executing long ferries over high seas. Problems of In-Flight feeding, In-Flight urine disposal were addressed to by designing, fabricating and indigenizing utility and urine bags. Various Emergencies of Aero medical concern were encountered in the ferries. Active participation of the Aviation Medicine Specialist in all the aspects is show cased in this paper.

Aerospace Technology and Its Applications in Dentistry
Sqn Ldr Anjali, SK Mehta, Air Cmde DK Taneja

The newer dental materials of recent years have been adapted from those used in aerospace technology. Before the 1950s precious alloys were used in orthodontic practice primarily because nothing else could tolerate intra-oral conditions. After the initial years of struggling with stainless steel wires, the orthodontists took the lead in exploiting metallurgical and material advances made in aerospace technology. The high performance aircrafts of the 70s were made of titanium which inspired further investigation in dental field. This is not limited to the search for better materials but, in fact, spills over most newer technologies for the purpose of imaging, metal fatigue studies, better dental drills, x-rays, 3-D reconstructions etc. This article traces the evolution, development, and characteristics of dental materials and explores the many innovations that have been derived from original research carried out in the field of aerospace technology. Some of the outstanding derivations are high grade biocompatible materials; transparent brackets derived from transparent polycrystalline Alumina used in missile tracts; spacecraft tile technology enhancing the dental filling materials; Shape Memory Alloys (SMA) leading to various NiTi orthodontic wires; and the present day research in satellite sensors and probes that could help replace the age-old dental drill with lasers.

Accelerated Bone Healing Using HBO Therapy for Patients Treated With Enucleation of Large Cysts of the Jaws
Dr. S Girish Rao, Wg Cdr CK Ranjan, Dr AS Aravind

Some jaw cysts reach large sizes because of their growth pattern and will be many a time diagnosed incidentally on routine radiographs. When pathologic tissue is surgically removed, it leaves behind large defects in the bone, for which the conventional method of treatment involves grafting the defect with bone graft material with high osteogenic potential like autogenous cancellous bone and waiting for its full regeneration. Hyperbaric oxygen (HBO) therapy helps in early bone regeneration by increasing tissue vascularity and has been routinely used in management of osteo-radionecrosis of the bones. In this preliminary study, an attempt has been made to study the enhancement of the osteogenic potential of local bone by providing HBO therapy as an adjuvant or supplementary therapy in cases of jaw cysts that left large defects in the bone due to surgical excision. The initial findings show significant improvement in osteogenesis, bone regeneration and reduction in the post surgical recovery period for attaining bone maturity. The study also suggests the redundancy of introducing bone grafts and thereby reducing patient risks and donor site morbidity. However, a larger and protracted study is being carried out to confirm these findings.

Comparison of Baseline Oxidative Stress and Antioxidant Levels in Morbid and Healthy Subjects and After Exposure to Hyperbaric Oxygen
Wg Cdr P Kharbanda

Oxidative stress was evaluated in 42 patients who were taken up for hyperbaric oxygen therapy (HBOT) at IAM. Lipid peroxidation product, malondialdehyde (MDA), as a measure of oxidative stress was assayed in these subjects and Superoxide dismutase (SOD), Vit C and Vit E were estimated to evaluate the antioxidant levels in the body. 12 healthy subjects were taken as controls. One aspect of the study was to compare the baseline levels of MDA, Vit C, Vit E and SOD between the morbid and healthy subjects and the second aspect was to study the changes in the same parameters after exposure to hyperbaric oxygen (HBO). Cross-sectional analysis between the morbid and healthy revealed that the resting MDA level was significantly higher (p < 0.05) in patients. There were no significant differences in the Vit C and Vit E levels between the two groups. SOD levels were found to be significantly higher in the healthy subjects as compared to the morbid. Longitudinal analysis revealed that exposure to hyperbaric oxygen did not lead to any increase in the MDA level in both groups. There was a significant (p < 0.05) decrease in Vit C both in the patients and healthy group after being exposed to HBO. On the contrary the Vit E levels were found to be significantly increased in both groups. As a result of HBO the SOD was found to marginally increase in both groups but the increase was not significant (p > 0.05). No significant interaction was found between the group effect and exposure effect. This study corroborates the fact that morbidity is associated with increased oxidative stress, which is evidenced by increased baseline levels of MDA. As further proof, SOD, which is the first line enzymatic defence against oxidative stress was found to be lower in the patient group. This study also vindicates the, more than three decades old, HBO protocol being followed at IAM. The protocol of 2.5 ATA over 90 minutes does not pose any oxidative stress and the patients can be safely treated without any fear of oxygen toxicity.

Changing Trends in Management of Thoracolumbar Spine for Aircrew
Col PK Sahoo, Col P Singh, Lt Col HS Bhatoe, Lt Col TVSP Murthy, Lt Col (Mrs ) K Sandhu, Wg Cdr (Mrs) A Chaturvedi

A retrospective analysis was carried for sixty patients with thoracolumbar spine injury operated during Jan 2001 to Dec 2003. Fifty (84%) were male and ten were female patients.Thirty six (60%) sustained injury by vehicular accident and 24 (40%) due to fall, ejection and obstacle crossing. There were four patients with associated head injury, seven with extremity, four with chest and two patients with abdominal injury. All patients presented with features of spinal cord/ cauda equina injury and evaluated with Frankel's neurological grade at admission. Eight patients presented with grade 'A', two grade 'B', thirty six grade 'C', fourteen grade 'D' neurological deficit as per Frankel's classification. Plain radiography, Computerised Tomography (CT) scan, and Magnetic Resonance Imaging (MRI) of thoracolumbar spine revealed fracture L1 in 32, D12 in 14, D 11 in 02, L2 in 05, L3 in 01 L4 in 04 and upper thoracic in 02. There were 54 type 'A' and 06 type 'C' fracture of thoracolumbar region as per AO classification. Pedicular screw and titanium rod (3D- TSRH System) in 32; cage placement +pedicular screw & Titanium rod in 05 patients; corpectomy+ bone grafting+ plating in 06; corpectomy, cage placement in 07 ; corpectomy, cage placement+ plating in 10, were carried out. Outcome was evaluated at two months, six months and one year in Frankel's grade. The outcome was Frankel's 'A' 08 Frankel's 'B' 02, Frankel's 'D' 23 and Frankel's 'E' 27. Ten patients did not show any recovery. There was wound infection in two, mal-alignment of cage in two and lateral placement screws were found in two patients. Revision surgery was not carried out, as the patients were stable. The implants were in position during post-operative follow up. The study revealed, there was good reduction, decompression and stabilization in all patients. Patients with incomplete spinal cord injury showed excellent to good recovery and patients with initial Frankel's 'A' 'B' did not show any recovery. The patients were mobilized early with external support after spinal stabilization.

Prevalence and Significance of Incidental/Non Traumatic abnormalities of spine detected on MRI following ejection
Wg Cdr A Alam

Introduction: Radiological evaluation of the spine following aircraft ejection has always been complex and at times controversial. MRI with its multiplanar imaging capabilities and flawless delineation of spinal anatomy has made this task simpler. Apart from revealing the injuries directly sustained as a result of the ejection, MR imaging detects abnormalities in the spine which are not a direct consequence of the ejection process. These abnormalities, if severe can affect the flying prospects of the pilots. Objective: The aim of this study was to analyze the pattern of incidental / non-traumatic abnormalities of the spine detected on MRI done as part of post ejection evaluation. The study also attempts to evaluate the significance of these abnormalities and their impact on the flying career of the pilots. Method: A detailed analysis of incidental / non-traumatic abnormalities detected on spinal MRI in 60 post ejection cases was carried out. The analysis included abnormalities like disc degenerative disease, facet joint arthropathy, spinal canal stenosis and spondylotic changes. The MR scans were interpreted independently by two experienced radiologists trained in MR imaging so as to minimize inter and intra reader variability. Conclusion: The study revealed that the prevalence of incidental / non-traumatic abnormalities of the spine is comparable to that of the normal population. However its presence has created difficulties in the aeromedical disposal of the ejectees. The severity and not just the mere detection of these incidental abnormalities, coupled with clinical and human engineering evaluation should be the criteria in the final aeromedical disposal of these pilots; the ultimate aim being to conserve trained manpower but not at the cost of flight safety.

Prevalence and Risk Factors for Post-Traumatic Stress Disorder and Depression in Aircrew after Ejection

Wg Cdr NF Misquitta, Wg Cdr G Gomez

Introduction: The aim of this paper was to study the prevalence of Post-traumatic Stress Disorder (PTSD) and Depression after ejection, to identify risk factors specific to aircrew, and to assess the comorbidity of PTSD with Depression. Materials and method: Subjects were Indian military aircrew who had experienced an ejection (n=19). Controls were active duty pilots flying ejection seat aircraft (n=14). Demographic, service related, and ejection related data were collected. Consenting pilots were administered the Trauma Symptom Inventory (TSI), and the Hamilton Depression Inventory (HDI). Results: 5.3% of the ejection group had significant PTSD and Depression symptoms. Aircrew that ejected had elevated scores on the TSI Defensive Avoidance scale (t=2.08, df=31, p=0.02). Single status pilots who ejected had higher PTSD (t=2.04, df=13, p=0.03), and HDI scores than married pilots. The ejection group had significantly higher scores on the HDI Agitation-Disorientation dimension (t=2.1, df=31, p=0.02). Higher HDI scores were associated with longer flying hours on aircraft type (t=2.177, r=0.49, p<0.025). Discussion: PTSD and Depression are prevalent and comorbid in aircrew after an ejection, and occur comorbidly. Single status is associated with a higher risk for PTSD and Depression. Somatisation and longer flying hours are associated with Depression.

Air To Air Refuelings : A Comprehensive Aeromedical Overview
Wg Cdr VN Jha, Air Cmde UB Mathur VSM

Air to air refueling (AAR) has become a reality in IAF. The usual fighter Ops of 30-60 min has now become 5-6 hrs sortie. The Refueler is also capable of flying for more than 12 hr at a time. For these long duration Ops, strengthening of the weakest link i.e. the man, in the man-machine-mission concept, has become essential. The pilots require in-flight food, water and urination. The oxygen management becomes critical both in terms of prolonged in-mask safety pressure and the on-going practice of using 100% oxygen during night Ops. Lowering of the oxygen mask for in-flight feeding during operational flying poses different problem. The other aeromedical factors including permissible length of continuous vigilance task, aspects of monotony, biorhythm, cumulative aviation stresses, fast changing ground perspectives and requirement of stringent physical fitness need equal consideration. Problems related to flight refueler are somehow different from fighter operations owing to its multi-crew, multi-provisioned, high pressure cabin. Isolation of the air refueler director (ARD) in the aft cabin has been discussed.

Surface Electromyogram as an Indicator of Muscle Fatigue in Neck Muscles
Wg Cdr S Chowdhary, Dr Sangeeta Baxla, Mr Aravindakshan, Dr AS Aravind

Surface electromyogram (SEMG) is being increasingly used in the study of muscle activation and muscle strength. Interest in the use of surface EMG as a tool for detecting the onset of muscle fatigue had been increasing over the past two decades. This has come about with improvement in the recording instruments and in the use of computers in the analysis of the SMEG record. With the use of Fast Fourier transforms the amplitudes of the frequency components have been studied. Shift in the frequency with the increasing duration of contraction has been repeatedly noted and suggested as a potential marker of fatigue. In the aviation context, there is a rising concern on the issue of fatigue in the neck muscles with the use of NVGs in helicopter operations. As the NVGs impose an additional load of about 1kg on the head and the aircrew is also exposed to whole body vibrations, the apprehension of occurrence of fatigue in the neck muscle is a justified concern. Surface electromyography characteristics were studied in the neck muscles of subjects exposed to whole body vibration stress while wearing a flight helmet loaded with a NVG. Six subjects were exposed to vertical oscillatory motion on a uniaxial vibration platform. The splenius capitis neck muscles on both sides were instrumented.SEMG records at 70% MVC were obtained both before and after forty-eight minutes of vibration stress. The parameters studied were the total power, mean frequency and median frequency of the power spectrum obtained with the use of Fast Fourier transform of the SEMG data. The pre and post exposure values were compared and their difference was tested for significance. Statistically significant difference at p<0.05 was found in the median frequency shift in the right splenius capitis muscle. This indicates that neck muscle fatigue is an issue of concern in heliborne operations with helmet mounted devices.

Approach to a Case of Dyspepsia
Wg Cdr B Nandi

Dyspepsia is defined as pain or discomfort centered in the upper abdomen. It includes symptoms like epigastric burning, bloating, early satiety, acid reflux, nausea and vomiting. It accounts for 50-70% of all gastrointestinal complaints seen in general medical practice. Dyspepsia can be organic or functional. Gastro-esophageal reflux disease, peptic ulcer, acute and chronic gastropathies are the common causes of organic dyspepsia. Visceral hypersensitivity, dysmotility and psycho-social factors underlie the pathophysiology of functional dyspepsia. Approach to a patient with dyspepsia should be evidence based and dictated by age, presence or absence of alarm symptoms, co-morbidities and endoscopic findings. The primary care physician needs to discern which cases require immediate hospital referral and endoscopic evaluation and in which empirical therapy can be tried locally. Other important issue, which needs to be addressed include, when to eradicate Helicobacter Pylori, early versus delayed endoscopy and optimal duration of therapy. There is also a need to rationalize the use of antacids, H2 - blockers and proton -pump inhibitors keeping in mind their pharmacological profile and drug interactions.

Vertigo - "A Bird's Eye View"
Lt Col R Varadarajulu VSM

Vertigo is a very common neurological condition with a prevalence of 2 per 1000. The causes of vertigo encompass a large number of conditions starting from peripheral vertiginous disorders like labyrinthitis, vestibular neuronitis, Meniere's disease & BPPV to central causes like TIAs in posterior circulation, spondylotic vertigos due to vertebral artery kinking, whiplash injuries and rarely due to tumours, demyelinations or drugs. Thus it is imperative for the first look physician to have a bird's eye view of this condition to distinguish benign vertigos from sinister ones. The talk of 10 minutes will cover causes, pathophysiology, clinical approach, investigations and treatment of vertigo.

Syncope - Evaluation And Management
Wg Cdr H Madan

Syncope is a commonly encountered symptom in clinical practice and can be baffling to doctors providing primary, secondary or tertiary level care. While a large number of etiological conditions can cause the symptom of giddiness / light headedness, cardiovascular and neurological causes remain the predominant cause.This presentation will discuss a symptom guided, systematic approach to syncope. The main thrust of the discussion would be to highlight differentiating features between clinically benign causes of syncope from the more sinister ones. The role of various clinical methods in assessment of a patient with syncope - including bedside tests for autonomic dysfunction will also be discussed. Finally the aero medical importance of the symptom in aircrew with this symptom will be highlighted. The presentation will end with a brief overview of the various pharmacological and non-pharmacological therapeutic modalities available for the condition.

Rational Use of Antibiotics
Wg Cdr (Mrs) C Khati

A major contribution to human longevity and quality of life in the 20th century was the development of anti microbial agents. When used appropriately, these drugs are life saving. Indiscriminate use drives up costs of health care and more importantly, promotes emergence of bacterial resistance, rendering previously valuable drugs useless. The rational use of antibacterial agents depends on an understanding of their mechanisms of actions, pharmacokinetics, toxicities and interactions. Even more important is to comprehend microbial strategies for resistance and in-vitro susceptibility. Finally, patient associated parameters such as, site of infection, immune and excretory status of the host etc. are critically important inputs in making therapeutic decisions. Learning objective: Provision of a brief insight into making an informed choice of antibiotic in common clinical situations.

Integrated Management of Childhood Illnesses: The Guidelines
Wg Cdr Daljit Singh

When a sick child is brought by the parents to a doctor, the doctor, at times finds it difficult to evaluate the sick child. The integrated guidelines try to bring together the simplest possible expression of what needs to be done to treat children in order to reduce mortality or to avert significant disability. The guidelines rely on detection of cases based on simple clinical signs. A careful balance has been struck between sensitivity and specificity using as few signs as possible and ones that health worker and doctors of varying backgrounds can be trained to recognize accurately. In addition, the health workers are taught about prevention of diseases through the promotion of breast feeding, counselling to solve feeding problems and improving immunization coverage by ensuring immunization of sick children. The health workers are taught about classification and triaging of the illnesses, which helps the health provider to decide what treatment or advice to offer. This could be one of the following: a) urgent referral to the hospital b) specific medical treatment and advice or c) simple advice in home management. The mother is also advised on the signs, which indicate that the child should immediately be brought back to the health worker. In children below 2 years of age and those who are malnourished, feeding is assessed; any feeding problems are recorded and counselling on feeding problems provided. Follow up instructions for various conditions are provided and explained to the mother.

Blood Banking: Newer Concepts & Realigning Efforts with Risks
Gp Capt Yashpal Jalpota

Since the discovery of blood groups ABO by Karl Landsteiner in 1900 there have been many changes in blood banking, especially in last one decade. In India blood is classified as a drug under Food & Drug Cosmetic Act. Blood transfusion is the vital part of the modern health care system without which efficient medical care is impossible. The aim of blood transfusion services should be to provide effective blood and blood products, which are as safe as possible, and adequate to meet patients' need. Blood bank should follow recommendations of the International Society of Blood Transfusion and Immunohematology (ISBTI) & the World Health Organisation (WHO) recommendations. Screening of all donors for evidence of transfusion-transmitted infections and mechanism of self-deferral of potential donors who are at high risk of the infection, have been quite successful to control this route of transmission of infections. At present we are screening the blood for HIV-I/II, HBV, HCV, Syphilis & Malaria only. In near future we shall be required to do tests for HIV p24, HIV-NAT, HTLV-I/II, HCV-NAT, HBV-NAT, Parvo virus, Cytomegalovirus, Prions etc which are not presently done because of high cost or low risk with these viruses. Whole Blood transfusion is out-dated now. Blood components like packed RBC's, Washed RBC's, FFP, Cryoprecipitate, Platelets, Neocyte, Leucocytes etc are preferred products since one unit can benefit many patients at a time and is less hazardous. Medical officers need to be sensitized to new types blood banking practices like Leucocyte-reduced red blood cells, Autologous transfusion, Leucocyte-depleted platelets, Therapeutic Hemapheresis & Irradiated blood. In future a synthetic blood and Robotic blood bank will be a reality. At present there is no replacement for human blood. Inspite of testing, blood is a dangerous product only to use if must. Motto of safe blood practices remains "RIGHT BLOOD PRODUCT AT RIGHT TIME TO THE RIGHT PATIENT IN RIGHT QUANTITY".

Resuscitation of Patients in Peripheral Medical Units, SMC and MI Rooms
Lt Col SK Singh VSM

The management of medical and surgical emergencies in peripheral medical units, SMCs and MI Rooms presents a constant challenge to the duty medical personnel. It requires significant clinical acumen and prudent judgment to tackle these pre-arrest situations and prevent catastrophic cardiac arrest. All personnel also need to be current with the skill necessary for cardiopulmonary resuscitation (CPR) to revive such arrests. This article aims to provide a step-wise review of cardiopulmonary resuscitation (CPR) with international recommendations on the subject. It highlights the Comprehensive ECC Algorithm and practice of standard protocols using the Primary and Secondary ABCD survey. The recent advances in these protocols that are being contemplated since the last recommendations put forth in 2000 have been discussed. In addition, it aims to provide a simplified review of resuscitation and management of medical emergencies like poisoning, drowning, choking, hanging, coma etc, over and above the basic life-support protocols, till they can be stabilized and further transferred out to nearest hospital for definitive management. The difficulties encountered in managing medical emergencies in field are many and efforts must be made to provide training and equipment towards better health care.

Management of Head Injury
Lt Col HC Pathak

Head injury is a leading cause of morbidity and mortality all over the world. The number of head injury patients is continuously increasing due to rapid increase in number of vehicles and urbanization. Head injury involves young people in their most productive year's and imposes a great burden on society.The mortality from severe head injury world wide has declined in recent past due to wide availability of emergency medical services, critical care units, availability of CT scan and early surgery. Securing airway and maintaining blood pressure is of the utmost importance right from the site of accident to facilitate healing of injured neurons and to prevent secondary injury to damaged neurons. CT scan head delineates most of the traumatic intracranial pathologies. Hematoma more than 30 ml in size and midline shift more than 5mm on CT Scan requires urgent surgery. Intracranial pressure (ICP) monitoring is indicated in all severe head injury patients. Control of ICP is essential to maintain adequate cerebral perfusion. Clinical trials of many drugs like super oxide dismutase, NMDA blocker, Methylphenidale is going on which has oxygen free radical scavenging activity to protect brain from ischemic damage. Mortality from severe head injury in India is still depressingly high varying from 40-70%. The important cause of death is raised ICP, brain hypoxia and ischemia. Despite significant research in central nervous system regeneration, researchers have been unsuccessful in reversing the effect of injury to the brain. Hence prevention is the key. With proper road traffic safety measures the incidence of road accidents and head injury can be brought down significantly.

Practical Problems in Management of Extensive Burns
Wg Cdr T Roy

Extensive burn is one of the most dreaded problem faced by the medical fraternity, as well as the society at large. In spite of multiple approaches to solve the problem and extensive research in the field, the mortality has only improved marginally. The reason has primarily been the prohibitive cost, inadequacy of manpower and non-availability of skin substitute at affordable cost. Once the patient's life is saved, multiple variables determine the final outcome of the patient's quality of life. Most of these although cannot be obviated, can be modified by simple means which are available to us once the patients leaves the burns unit and is thereafter in the care of Station Medicare Centre. These involve application of proper splint to avoid development of disabling contractures, proper pressure garments to minimize scar hypertrophy, application of regular emollients to prevent development of cracks and fissures, avoidance of sunlight to prevent hyper pigmentation of skin etc. However if these cannot be controlled by the above means, intervention in the form of either cosmetic relief, camouflage by an experienced beautician or surgery are required. The aim of this paper is to provide a working protocol for the medical fraternity of the Armed Forces considering the extent of the problem, constraints that we face in SMC for the acute management of burns and the problems of evacuation as well as the postoperative management. A brief note of the DO's and the DONT's is also presented.

Cervical Cancer Screening
Gp Capt S Venkataramani

Cervical cancer, one of the most common malignancies in women, is nearly 100% preventable. There has been dramatic decline in the incidence of cervical cancer over the past 50 years - in large part due to the increased use of screening - yet significant numbers of women still contract the disease. Deaths from carcinoma cervix could be virtually eliminated with timely and effective screening. Squamous cell cervical cancer is an ideal disease for screening because of the long preclinical phase, which permits early detection. Despite the recognized benefits of Pap smear screening, substantial subgroups of women have not been screened or are not screened at regular intervals. Screening and early detection can improve women's quality of life. An average 20 year old woman can reduce her lifetime risk of cervical cancer from 2.5% to 0.7% through regular screening. The cervical cancer cure rate approaches 100% if the patient is treated when the cancer is in an early stage. Pap testing is currently the most practical method of detecting cervical cancer in localized or pre-malignant stages.

Obstetrical Hemorrhage
Wg Cdr BR Barakol

Obstetrics is a "bloody business". Obstetrical hemorrhage contributes for the maximum percentage for maternal mortality in advanced countries. Obstetrical hemorrhage is most likely to be fatal in circumstances in which blood or components are not available immediately. The establishment and maintenance of facilities that allow prompt administration of blood are absolute requirements for acceptable obstetrical care.Hemorrhage may be antepartum [Placenta praevia or placental abruption], or it most likely develops postpartum [from uterine atony or genital tract lacerations]. Bleeding from placenta praevia is painless, profuse due to placenta being in the vicinity of cervix. Placental abruption is premature separation of the normally implanted placenta leading to catastrophic events like consumptive coagulopathy. Postpartum hemorrhage is the consequence of excessive bleeding from the placental implantation site, trauma to the genital tract and adjacent structures, or both. It contributes to the 50% of maternal deaths from hemorrhage.Postpartum hemorrhage is the loss of 500 ml or more of the blood after completion of the third stage of labour. It can be due to atonic uterus or retained placenta or due to the trauma to the genital organs. It requires prompt diagnosis and management to avoid catastrophe.

Primary Management of Common Ocular Conditions
Wg Cdr D Joshi

Common ocular conditions, which are encountered by the primary care physician, are discussed with special emphasis on initial management and decision-making regarding promptness of referral. Patients with a variety of foreign bodies falling into the eye often report with considerable pain and discomfort. These include wind blown dirt, tree leaves, plant sap, cooking oil, whitewash and chuna at home and metallic particles or chemicals at the workplace. Basic ophthalmic evaluation and thorough eye lavage using topical anaesthesia, which forms the cornerstone of management, will be elaborated. Conditions such as stye, chalazion, blepharitis and allergic conjunctivitis are often seen and effectively managed by the medical officer. Current management practices of the same are discussed. Elderly patients with painless progressive visual loss and thought to have a cataract often have underlying conditions such as glaucoma and age related macular degeneration. Indications for referral and correct technique of instilling anti-glaucoma medications are discussed. Certain aspects of refractive errors in children are highlighted. The value of school medical examination is emphasized. Some common queries by eyeglass and contact lens users will be addressed.

Foreign Bodies in Upper Aerodigestive Tract
Wg Cdr (Mrs) K Jauhar

The problem of foreign body ingestion and aspiration is not new, but significant dilemmas in the diagnosis and treatment of this problem remains despite major advances.Foreign body ingestion and aspiration can affect persons of any age, but the vast majority of these accidents occur in children under age 5 yrs. It is estimated that about 1500 deaths occur annually related to the ingestion of foreign materials and 3000 deaths occur annually due to complications of foreign body aspiration. Suffocation resulting from foreign body ingestion and aspiration is the third leading cause of accidental death in children under age 1 yr and fourth leading cause of death in children from age 1-6 yrs. In children, safety pins were a frequently implicated object in the past, but since the introduction of disposable diapers, these events most commonly involve coins. In adults, food is by far the most common foreign body of the upper aero digestive tract. Due to decreased sensation of food in the oral cavity in denture wearers, small foreign bodies such as fish bones are commonly found lodged in the oropharynx, in addition to the dentures themselves. In addition, hurried eating can lead to large boluses of meat lodging in the esophagus. A prior history of esophageal pathology such as tracheoesophageal fistula increases the risk of foreign bodies impaction of food in the esophagus. Esophageal stricture obstructing masses may present as esophageal foreign body. A thorough inspection of the food passage must be done in these cases. Presentation of some unusual foreign bodies, which were removed from the digestive tract are being presented. Also laying emphasis of the DO'S and DONT'S in the management of foreign bodies in the upper are digestive tract are stressed.

Management of Maxillofacial Injuries in Armed Forces - Challenges and Current Perspective
Sqn Ldr SK Kaushik, Air Cmde DK Taneja

The Maxillofacial skeleton of the human body represents a unique and an intricate architecture blending the esthetics of a pleasing facial profile with that of the mechanical function of the various vital organs. Fractures of the maxillofacial region represent a remarkable dilemma from surgical, reconstructive, psychological and social standpoint. Trauma to the maxillofacial region mandates special attention as contained within the face are specialized functions including vision, hearing, smelling, respiration, mastication and speech. This can lead to devastating disfigurement and post-traumatic deformities that greatly influence the patient psychologically and limit his social rehabilitation, sometimes permanently. Modern diagnostic armamentarium like the 3D reconstruction computed tomography coupled with recent advances in biomaterials like titanium mini & micro plating systems have paved the way for a comprehensive surgical management in early recognition and prompt definitive management of these injuries. In the setting of a tertiary speciality health care hospital, the cases of maxillofacial fractures are not only those of the local serving personnel and their dependants but also transfer in cases from the peripheral outstation service hospitals under chain of casualty evacuation. The commonest etiology being high speed motor vehicle road traffic accidents more so due to driving under the influence of alcohol, the other various causes are inter personnel violence and human battering, sports related accidents, occupational industrial hazards, animal assaults, natural calamities, etc.

Abstract of Posters Presented

An Epidemiological Study of Stress Fractures among Flight Cadets at Air Force Academy
Wg Cdr KS Raju, Wg Cdr Sanjiv Sharma, Gp Capt RC Yadav, Wg Cdr MV Singh, Wg Cdr V Tandon, Sqn Ldr S Hemant

Abstract
Introduction: Stress fracture is common among Flight Cadets during military training. These fractures add to the morbidity and loss of precious training hours. Some cadets with recurrent or multiple stress fractures had been re-flighted or invalided out of service in past, resulting in attrition and economic loss to the exchequer. Methodology: Retrospective study of one hundred and fifteen stress fractures among Flight Cadets for the past five years was analyzed from the available medical documents. Results: The incidence of stress fracture among Cadets at Air Force Academy varied from 1.8% to 12.5% in the last five years. The least incidence was in the year 2004. Incidence of stress fracture is significantly higher in ground duty branch and female cadets as compared to flying branch trainees. Tibia is the commonest site of fracture in both sexes. The fracture occurred within 8 weeks of onset of training in 70% of the cases. Average duration of hospitalization was 24(±19) days. Discussion: Incidence and causative factors of stress fracture are studied. Most of the cases were managed conservatively with rest and immobilization. Preventive measures adapted at AFA which helped in significant reduction in incidence of stress fracture are discussed. Conclusion: Recommendation for modification in training schedule to contain the incidence of stress fractures amongst Flight Cadets is made.

The Evaluation of Noise Hazards due to Various Aircrafts in Indian Air Force
Wg Cdr U Kumar

Noise is inseparable from aviation. Air Force personnel are exposed to the hazards of noise because of working and living near the close proximity of aviation activities. Study was conducted at Air Force Station Jamnagar to evaluate the noise levels at various places. Noise levels at tarmac, TACDE, hangers, ATC tower and several other work places ranged between 99-125.5dB. These were dependent on the speed of the aircraft, flight altitude and the distance between the aircraft and the people on the ground. During the ground run and maintenance of aircrafts the noise levels ranged between 120-135dB. Maximum noise of 140dB was noticed at tyre checkers point near runway controllers hut. Ground run and the hovering gives out both periodic and non periodic broadband noise with strong tonal components. This type of noise has adverse auditory repercussions for the people on the ground and also for the cabin crew because of intense and prolonged exposures. The incidences of hearing impairments in the ground crew were higher compared to the pilots. This may be due to the difference in the exposure dose and the level of protection by the ear defenders, helmets and other communication devices. The incidence of mild, moderate and severe hearing impairments were significantly higher in the ground duty personnel compared to the pilots. Ground duty personnel showed decline in hearing sensitivity in more number of frequencies compared to fighter pilots and most affected frequency was 6kHz. Repeated exposure to brief but intense noise inflicted moderate to severe degree of hearing impairments in about 5% of school children and 24% of the families residing in the close proximity of the take off point.

A Study of Relationship Between Visuospatial Abilities and Range Firing Score.
Wg Cdr CS Thakur*, Wg Cdr VV Joshi #

Air to ground weapon delivery is an important aspect of fighter flying. Visuo spatial abilities are one of the important attributes in determining the pilot performance in various components of flying. It is presumed that a person who has good spatial orientation abilities is likely to perform better at armament range. This study is based on the hypothesis that pilots with good visuospatial orientation abilities will have better score of Air to ground weapon delivery (range firing score) and flying performance in general. The study was conducted on two groups of subjects: group I comprised of 10 ground duty personnel and group II had 58-fighter aircrew as subjects. Visuospatial abilities in both the groups were determined by administering a simple paper and pencil test called as Flag Test, which is test of mental rotation, with responses being evaluated for accuracy and speed of performance. Range firing score was based on actual performance of aircrew in gunnery, rocketry and bombing at the firing range. The performance in flying was based on the rating that the squadron supervisors' awarded to the aircrew. The various scores thus obtained were analyzed statistically using co-relation analysis and ANOVA to find out relationship between visuospatial abilities, range firing and general flying performance. Comparison has also been made between such abilities amongst aircrew and ground duty personnel. Results of the study showed positive co-relation between Air to Ground range firing score and visuospatial abilities. Aircrew were found to have better visuospatial abilities than ground duty subjects. These results have been discussed and based on this, recommendations have been made about inclusion of tests of visuospatial abilities as part of pilot selection battery.

Need For a Non-Punitive Reporting System in IAF: A Perspective
Wg Cdr Atul Gupta*

Human error continues to account as a leading cause in aircraft accidents all over the world. In IAF, it accounts for nearly 45-50% of the accidents. Though human error cannot be eradicated, detailed knowledge of the sources of error facilitates the development of safety programs. Internationally, numerous agencies involve simultaneously, investigating into accidents/incidents. However in IAF, formal investigation, in the form of a court of inquiry, is the only agency that investigates into all cause factors leading to the accident/incident. Such a system has its own drawbacks. Recommending punitive action impedes revealing all cause factors for a comprehensive analysis of the accident/incident. A need to introduce a system of non-punitive reporting system is therefore felt to provide a comprehensive feedback on all possible sources of error so that an effective safety program can be developed.

SUICIDES IN IAF: PREVENTIVE MEASURE
Wg Cdr RK Ranyal

Introduction: The increase in incidence of suicides in IAF is a cause for concern. Such incidents have an adverse effect on efficiency and moral of the unit. As per WHO every six minutes a suicide occurs. The year 2010 has been projected to herald the onset of a suicide epidemic. In Indian Air Force there are on average 13.5 suicides cases per year. In 2003 there were 24 cases of suicide. In defence services suicide forms approximately 0.11% of total mortality. Counselling centre is an effective option to the individual in distress and discourage them from taking the extreme step of suicide. Guidelines: One counselling centre to be established at each station, which is accessible, and provides 24 hrs help line. Dedicated and trained volunteers to man these centres. Wide publicity to be done. AIIMS, New Delhi will design and conduct training 'Capsule Course' for group of Psychiatrists, RMO and medical officers. Same capsule courses can be conducted at IAM, AFCME for all the medical officers and non-medical volunteers. It can form a part of Primary Aviation Medicine course. Principles: The foremost step is taking into confidence the distressed individual and offering help without strings and without being judgmental. The privacy of the individual must be respected. Commanders at each level are to be sensitised. More interaction and close watch at grass root level by Section Commanders and Supervisors is required. Early identification of high-risk group is essential. Information, education and communication are key factors. People of high-risk group or people exposed to stress may be subjected to questionnaires to identify any personality or mood disorder. Conclusion: Counselling centres at station level is a viable proposition. These are not difficult to organize and require no special infrastructure. These would benefit service personnel and their families.

Microcomputer System for Early Detection of High-Altitude Pulmonary Oedema
Dr. Munna Khan, R Narang

Introduction: High-altitude pulmonary edema is a potentially fatal condition affecting otherwise fit and previously well individuals at altitudes in over 3000 m. In pulmonary edema (PE) intrathoracic fluid accumulation occurs in interstitial and /or alveolar space of lungs. Mitral stenosis, hypertension, aortic valve disease, cardiac infraction, and stroke can also cause pulmonary edema. Methods: A microcomputer system for early diagnosis of pulmonary edema has been developed and tested on normal subjects and on patients having PE due to cardiac diseases. The microcomputer system uses, voltage signal corresponding to predicted and measured transthoracic electrical impedance (TEI) values. The voltage signals are being converted into dc voltage level after proper amplification and fed to analog to digital converter. The digital values are stored at standard locations in microcomputer. Thoracic dimensions of subjects measured using inch-tape and vernier caliper are fed to the microcomputer for predicting the diseased free TEI. If the measured impedance is lower than the predicted one, then system calculates PE (expected fluid accumulation) in milliliter and displays on the video-screen the predicted and measured TEI values. The system is completely non-invasive and requires only skin electrodes to be applied to the patient. The system has been tested on 20 subjects showing 10 normal (7male and 3 female) and 10 patients (7 male and 3 female) in the Cardiothoracic Centre, All India Institute of Medical Sciences, New Delhi. Results: The microcomputer system quickly detects PE quantitatively in the patient with heart disease. The range of estimated fluid for normal subject is from 10 ml to 30 ml. While patients with different cardiac disease have shown the range of fluid accumulation from 35 ml to 210 ml. Conclusion: Microcomputer system not only shows the presence of increased fluid but also estimates the amount of fluid accumulation. The system tested in the laboratory may be used to measure high altitude PE developed in the hypobaric chamber or at actual high altitudes.

Personal Medical Folders for Patients at SMC - A Pilot Project
Wg Cdr RK Pathni

It has been the practice in SMCs to record details of the visiting patients in registers. The reception maintains several registers. Usually a separate register is opened for personnel of each unit. And then there are registers for Officers, Officers' families, Ex-servicemen, Army & DSC personnel, Civilians, etc. A system of Personal Medical Folders for patients has been introduced in SMC, AF Stn Jaipur, in place of the age-old system of Sick-Report Registers. The aim was to deliver more personalized health-care to patients. We managed to do it at a low cost and the transition to the new system was quite smooth. With the introduction of this system all clinical details- past and present- of an individual and his family have been brought to one place. Prescribing and follow-up is much easier and linking of medical details within a family is also facilitated. It also ensures greater confidentiality of detail. This pilot project has proved to be very user-friendly and has definitely improved work efficiency as well as patient-care in this SMC. All involved - Patients, Medical Officers and Medical Assistants- have appreciated it. The system depends on the use of a Master Index Register - which is also useful as a single point source for all raw statistical data on patient care in the SMC. The procedures, changes involved and our experiences with this system over the last two years are outlined in this paper.

Aeromedical Evaluation of Defective Mask Oxygen Mk II (Mod)
Wg Cdr (s) Sanjiv Sharma (1), KS Raju (2)

Abstract
Background An operational hazard report (OHR) was raised for several defective Masks Oxygen Mk II (Mod) at a basic flying training squadron at Air Force Academy (AFA). This paper aims to present the aeromedical evaluation report of the defective oxygen masks.
Methods The defective oxygen masks were physically evaluated by Aerospace Physicians. The stored masks of similar batch, storage practices at the Flying Clothing Stores and masks in use with other pilots and their storage and maintenance practices were scrutinised. A structured interview of the users to find the details of the defects and maintenance practices was undertaken. A visit to a local rubber manufacturer to inspect the processing of India rubber and seek professional inputs was also made.
Results 19% of the 52 masks were found defective. The degree of deterioration was almost the same in all the defective masks where OHR was raised. This included tacky face rubber piece, residual black stain on touch and significant deterioration of rubber, making the masks unfit for use. 75.64 % ab-initio pilots responded to a structured interview. 15.25% observed defects in the mask at the time of issue itself. 8.47 % found progressive degradation on use, within 1-2 weeks of use. The changes were cracks on face-piece and melting, sticky rubber. Only 33.33 % were aware about the correct procedure for maintenance of the mask, and were practising it as well. 67.79 % were ignorant about the procedure to replace any defective flying clothing.
Discussion Existing practice of evaluation of flying clothing at station level, with focus on Oxygen masks, is discussed. The probable cause of defect in Oxygen masks was premature aging due to use of recycled or old rubber or inadequate heating of processed rubber mould leaving it incompatible for use in tropical conditions.
Recommendations Return of the defective masks, as per existing policies, for physical and chemical investigation was advised. Although OHR is an effective medium for seeking faster remedial measures, "Report on Failure or Defect in Air Force Flying Clothing" is recommended to be raised for investigation and improvement of flying clothing.
Keywords: Operational Hazard Report; Defect Investigation; Flying Clothing; Oxygen Masks; Life Support System
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(1) Wg Cdr Sanjiv Sharma, CO, 2 AMTC, AFA, Hyderabad 500043 (2) Wg Cdr KS Raju, AMTO, 2 AMTC, AFA, Hyderabad 500043

Effects of +Gz Acceleration on Indices of Heart Rate Variability
Maj Rahul Pipraiya, Lt Col KK Tripathi, Gp Capt MM Dogra VSM

Abstract
Objectives - To examine the effects of +Gz acceleration on autonomic control of heart rate and rhythm using time and frequency domain analysis of heart rate variability (HRV). Methods - 17 healthy male volunteers were subjected to +3Gz acceleration for 60 seconds (excluding 3 & 9 seconds of build-up and decay periods, respectively). No anti-G suit was used and the subjects remained relaxed throughout the run. ECG data were acquired, for 50 seconds each, before, during and after centrifugation (1st, 5th & 10th min of recovery) while the subject remained seated in gondola. Time and frequency domain analyses of HRV were made. The latter included both non-parametric (FFT based) and parametric (Maximum Entropy Method) techniques. Results - A significant decrease of all the time domain indices of HRV was noted suggesting a reduction in parasympathetic influences. Amongst the frequency domain indices, total spectral (0.04-0.40Hz) & HF (0.15-0.40 Hz) power exhibited a significant reduction during centrifugation. LF (0.04-0.15 Hz) power showed a significant increase only when normalized to total power. Both time and frequency domain indices reverted back to resting-sitting values between 5th to 10th min of recovery. A leftward shift of 'peak power frequency' (around which maximum power was concentrated) in the LF band was seen during centrifuge run, suggesting a change in the responsiveness of the effector organs. Conclusions - HRV indices provide valuable insight into the concerted behaviour of the two branches of ANS during human centrifugation. LF spectrum also provided information about responsiveness of the effector organs.

Psychosocial Factors Affecting Recovery from Musculoskeletal Disabilities in Aircrew: Evidence for a Proposed Hypothetical Model
Wg Cdr Narinder Taneja

Background: Varying patterns of recovery from musculoskeletal disabilities among aircrew has been observed and documented. It has been seen that for similar disabilities, the recovery period can be extremely varied. Moreover, disproportionate clinical symptomatology has been observed when compared to the radiological findings. Such aircrew are also subjected to psychological assessment for their motivation for flying and work need assessments. It appears that there are a host of psychosocial factors that may affect recovery of aircrew with musculoskeletal disabilities. Literature suggests evidence and postulates mechanisms for work related musculoskeletal disorders esp. those affecting the upper limbs and back. However, it is felt that psychosocial factors among aircrew may be much more varied, subtle and complex than those that have been documented for the general population. A hypothetical model postulating the role of various psychosocial factors that may possibly affect recovery from musculoskeletal disabilities is proposed. This model attempts to include factors that have been documented in literature and also have generic applications among aircrew. In addition, it also incorporates those that may be unique to the flying environment, organization and profession. Mechanisms and interlinking factors between various components of this model are elaborated. Implications and aeromedical significance: A better and clearer understanding of these, often very complex, psychosocial factors may provide insights into developing therapeutic and rehabilitative programs that could enable speedier recovery of aircrew with musculoskeletal disabilities. It would also enable conservation of trained manpower by returning trained aircrew to safe flying duties. The findings may have generic implications for comprehensive recovery from musculoskeletal disabilities. Further research is recommended to validate this model.

Evolution of Air-Sickness Management in the Indian Air Force
Sqn Ldr Piush Renjhen*, Sqn Ldr Vipin Sharma+ *Resident, 42nd Adv Course (Aerospace Medicine) +Graded Specialist (Aerospace Medicine)

Air Sickness is one of the most distressing and important impediments amongst the aircrew. The incidence is known to be more in ab-initio trainee pilots. This is compounded by the fact that flying training is a time bound programme and delays often lead to noncompletion of syllabi and contribute to the attrition rate of pupil pilots. The resulting loss of training hours and trained man-hours is a phenomenal loss to the exchequer. It has been a cause of concern for the aviators and the aeromedical fraternity. Airsickness, or Motion Maladaptation Syndrome is a modifiable condition that needs to be addressed jointly by the Aeromedical specialist, Flying supervisor and peer group. The role of the aeromedical group is exclusion of organic causes, understanding the individual case and institution of the best non-pharmacopeal therapeutic modality for the same. The role of the other groups is largely supportive. Indian Air Force (IAF) has had a comparable incidence of Airsickness to that in other countries. The evolution of Airsickness management in the IAF has been an ongoing process and has evolved to its current status where the management is entrusted to the medical fraternity at the Flying Training Establishments who have been managing the cases effectively. This has been possible through pioneering research and evaluations at the Institute of Aerospace Medicine (IAM). The research and evaluations at IAM have employed equipment like Gimble Mounted Tumbling Device (GMTD), Tonnie's rotating chair and Barany's Chair. Additionally, yogic exercises, physical exercises, biofeedback and modified Jacobson's Progressive Relaxation Exercises have been employed individually and in conjunction with psychotherapy. Currently, the Barany's chair exposure and yogic exercise therapy is being implemented. This training has been found useful for the trainee aircrew and has reduced the incidence of airsickness in these subjects. This paper presents the evolution of the various methods of airsickness management in IAF over the years.

Interplay Between G Stress & H Stress- Physiological Aspects
Sqn Ldr Pallavi Goswami, Wg Cdr PK Jain

Aviation stresses in the form of +Gz and heat exposure are known to affect the aircrew performance adversely. The most obvious physiological changes in stresses of heat and gravitation occur in the circulatory system. The two stresses impact upon and influence each other unfavorably in physiological terms. Studies on heat acclimatization have affirmed an improved ability to transfer heat to skin surface but the associated increase in the skin blood flow is more that compensated for by or other circulatory adjustments i.e. increased blood volume and reduced blood flow elsewhere, so that the overall strain on the circulation as judged by heart rate, BP and tendency to orthostatic hypotension is reduced. It is postulated in the present paper that exposure to heat decreases G tolerance and subsequent acclimatization to heat will improve G tolerance. The physiological basis for this hypothesis deserves further study and is expounded in the paper. An analytical discussion that merits considerable speculations whether acclimatization to heat will complement the outcome of maneuvers like AGSM that enhance a pilot's ability to combat G stress. The point that deserves attention, and possibly has important possible field applications, is whether acclimation to heat in simulated environment will improve G tolerance, and hence, aircrew performance.

Effect of Aircrew Clothing on Heat Strain Responses
Surg Lt Cdr B Vikas, Wg Cdr PK Jain

Heat stress is a common problem aboard Mig-21 aircraft, particularly during highspeed low-level flying. Fighter aircrew is expected to use various additional clothing to combat with other aviation stresses. Clothing profoundly affects heat transfer processes by adding thermal insulation, impeding air movements, and trapping water vapour at the skin. Fourteen male subjects, with a mean age 26.64±3.85 yrs, height 169.64±4.84 cm, body weight 65.19±6 kg and body surface area 1.75±0.08 m2 participated in the study. They were divided into two groups, (1) without Mig 21 flying clothing acting as the control group (CON group) (2) with Mig 21 flying clothing in the form of ZSH-3 Helmet, inner helmet, KM 32 oxygen mask, Mk II Anti G Suit and leather gloves in addition to the clothing used by CON group, acting as the experimental group (EXP group). Both groups were exposed to simulated hot dry environment at Wet Bulb Globe Temperature Index (WBGT) of ~38.1OC for sixty min. Sixty min of heat stress exposure in CON group resulted in the increase of Heart Rate (HR) from 79.71?5.9 beats/min to 101.71±4.61 beats/min, Oral temperature (Toral) from 36.56?0.28OC to 37.49+0.14OC, Mean Skin Temperature (MST) from 34.6±0.62 OC to 37.65±0.26 OC, Mean Body Temperature (MBT) from 35.91±0.30 OC to 37.54±0.13 OC, Sweat Production (SP) of 0.55±0.10 kg, Heat Accumulation Index (HAI) of 50.45± 9.11 Cal/m2 and Physiological Strain Index (PSI) of 2.51±0.39. Sixty min of heat stress exposure in EXP group resulted in the higher increase in HR, SP and PSI as compared to CON group. The changes in Toral, MST, MBT and HAI were not significantly different in both the groups. Our findings indicate that CON group showed significant heat strain in the simulated environment of WBGT ~38.1OC and extra flying clothing resulted in additional heat strain in the form of high HR, SP and PSI to maintain Toral, MST, MBT and HAI. * Surg Lt Cdr B Vikas, PG Trainee 24 MD (Aviation Medicine) Course, IAM Bangalore ** Wg Cdr PK Jain, Prof and Head Dept of Environmental Physiology, IAM, Bangalore.

An Analysis of Injuries in Aircrew in Non Fatal Helicopter Accidents:Implications for Aircrew Medical Evaluation Standards
Maj Amit Khurana, Wg Cdr N Taneja, Surg Cdr LJ Pinto

Helicopter aircrew who were involved in non-fatal helicopter crash landings/accidents and were evaluated at the Dept of Human Engineering from 2000-2004 were included for analysis. Database from the Dept was accessed to retrieve the details of aircrew evaluated at the Dept and their medical records were retrieved from MEC. A total of 11 aircrew from the helicopter stream were evaluated. Analysis reveals that 4 of them sustained compression fractured (36%) while one each had traumatic disc prolapse of the cervical spine and spondylolysis of LV5 detected post crash landing. Thus, six of the aircrew had spinal disability (54%). There has been only one reported study analyzing the nature of injuries in rotary wing aircrew among 35 helicopter accidents in New Zealand. The authors of that study report a spinal injury rate of almost 40%, which is very similar to our findings? Para 3.9.6 of IAP 4303 stipulates the spinal abnormalities that are compatible or not compatible with flying duties. However, it waives off these noncompatible spinal abnormalities for in-service candidates for non ejection seat aircraft. The findings of the study are discussed in relation to other medical fitness standards for in-service candidates reporting for aircrew medical examination at IAM. The authors feel that helicopter aircrew may be subjected to a much higher risk of spinal injuries compared to military aircraft equipped with ejection seats where the ejection forces are known. Spinal injury rate of 54% in this small study sample is relatively high compared to those reported in fighter aircraft. The fitness standards for aircrew duties not involving ejection seats need re consideration.