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 within the physiological tolerance of the human spine. The maximum acceptable limit for jolt factor is 300 G/sec with a peak acceleration of not more than 25 G for a period not exceeding 0.1 sec. The peak jolt factor and thrust in current ejection seats does not exceed 240 G/sec with a peak of 20 G. This allows sufficient margin of safety for variables like the pilot’s weight and the ambient temperature. 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

Eject! Eject! Eject! – Escape from an Aircraft

Escape from a crippled aircraft, be it a commercial aircraft, full of passengers, or a combat aircraft with one or two aircrew, ensuring a safe exit is the first and the paramount step towards survival. Unlike the combat aircraft with its ejection seats, transport aircraft, helicopter and most of the training aircraft, except jets, do not have such an assistance. Yet even with the ejection seat, the combat pilot has to recognize the emergency before deciding to pull the ejection seat handle. In an ‘act’ emergency, one must take actions accordingly, either abandon the take off or eject, to save precious time; whereas in a ‘react’ emergency, one must take corrective actions as required and yet, if the aircraft cannot be controlled or is below the minima for safety, one must make the decision to abandon the aircraft, before it is too late!  Continue reading

Sick in the Air: Motion Sickness/Air Sickness

Motion Sickness, characterised by nausea, pallor, cold sweating and vomiting, occurs when humans are exposed to unfamiliar motion stimuli, either real or apparent. The earliest known reference to motion sickness was ‘sea-sickness’ but now this term encompasses symptoms induced by any form of motion or even in the absence of physical motion it is known to occur during simulator rides or while watching movies. As per the motion environment which induces the symptoms, there are diverse names of motion sickness viz. sea sickness, air sickness, simulator sickness, space motion sickness etc. Since motion sickness can afflict any person, without him/her being ‘sick’ or ‘ill’, the word ‘sickness’ here has colloquial connotations. Continue reading