Category Archive: Military Aviation Medicine

Tired eh! Physical Cost of AGSM

Fatigue is the cost of correctly performed Anti-G straining manoeuvre (AGSM) to fight against the +Gz forces during air combat. Being an isometric exercise, akin to a 50 or 100 m race or weight lifting, the muscles maintain sustained contraction during AGSM to generate energy anaerobically. Thus time “to fatigue” and of “fatigue recovery” determine …

Continue reading »

Protection against the ‘G’

Average relaxed ‘G’ tolerance of combat aircrew varies between 4 to 5G, although the range may be 3 to 8G. Yet, one must note there are large individual variations in G tolerance and even in the same individual, the tolerance may vary on different days or different times of the day. It is here that …

Continue reading »

G-LOC – Then and Now…

16 September 2011. Reno, Nevada saw the tragic crash of a P-51Mustang [1] during the Reno Air Races. The findings of the National Transportation Safety Board suggests that the pilot had lost consciousness due to ‘overwhelming’ G forces [2]. This occurrence in a modified 1940’s vintage aircraft is no surprise, considering its high thrust to …

Continue reading »

NVG: Why the Neck Pains?

An informal query on a professional forum whether helicopter pilots suffer from neck pain while using NVG (1), a small group chose to share their thoughts and concerns. Eight of the respondents affirmed that they had discomfort or pain, including disc prolapse and pressure on the nerves as reported by one pilot each. However, there …

Continue reading »

NVG: Pain in the Neck!

Use of Night Vision Goggle (NVG) amongst helicopter aircrew is becoming a matter of concern [1]. On one hand, the pain in the neck is reportedly 29% amongst Australian helicopter aircrew [2], while it peaks to more than 90% Canadian Forces helicopter pilots with more than 150 hours of NVG flight [3]. Other likely causes …

Continue reading »

Decompression Sickness in HA Reconnaissance Aircraft

Pilots flying high altitude (HA) reconnaissance sorties are vulnerable to decompression sickness (DCS) due to, exposure to “pressure equivalent up to 29,500 ft (8992 m) of altitude for over 8 h” [1]. Cruise altitude of such HA reconnaissance aircraft viz. U-2 [2] and MiG 25 [3] is 70,000 ft and 74,000 ft, respectively. There are two …

Continue reading »

Eject! Eject! Eject! – Current Ejection Systems

Technological advancements in the design and development of ejection systems have resulted in significant improvements in the ejection seat and life support systems. Some of the advancements in ejection seat related sub-systems are discussed here.

Continue reading »

Eject! Eject! Eject! – Potential for Ejection Injuries

There are different phases of ejection, with potential for injury to the pilot. Sequentially, these phases are – (a) Canopy separation/ fragmentation; (b) Egress; (c) Ram Air/ Wind blast; (d) Wind drag deceleration; (e) Free fall; (f) Parachute deployment, and (g) Landing. As per the phase of ejection, a pilot can sustain various injuries with spinal injury being the commonest. 

Continue reading »

Eject! Eject! Eject! – Biodynamics of Ejection

The force moving an ejection seat must be sufficient to enable it to clear the tail of the disabled aircraft. To achieve this, the seat must accelerate from zero velocity to about 12.2 to 24.4 m/sec (40 to 80 ft/sec). This gives a rapid rate of rise of acceleration or jolt factor, which must remain …

Continue reading »

Eject! Eject! Eject! – An Ejection Seat

An ejection seat is a rigidly constructed metallic seat, which is forcibly ejected from the aircraft cockpit by means of an explosive charge. 

Continue reading »

Older posts «