Sid wrote:AFAIK back injuries during ejections happen due to a) malfunction in canopy release b) wrong siting posture during ejection c) low altitude ejections (which is solved in zero-zero ejection seats). The G-Load during ejections can be sustained by a fit pilot (irrespective of his/her weight).
No matter how good the posture gets - it is the acceleration
that does the damage to the spine and you cannot avoid acceleration in an ejection seat. The force is constant, and if the load is smaller the acceleration is higher. US seats are (now) being designed to safely eject people weighing in at weights ranging from the 5th to the 95th percentile of the US average. An average Indian woman weighs in at less than the 5th percentile of the US weight charts (check the charts) and an Indian woman in a US ejection seat will inevitably be subjected to a higher acceleration and will inevitably face an increased risk of spine injury no matter how good the posture is.
Even perfect ejections, from which pilots walk away have been shown to result in spinal microfractures. Some damage is inevitable because the spine is all spongy bone. IIRC a pilot in the IAF typically goes to hospital even after an eject from which he has walked away, and I think they are off flying for 6 months after such an event.
Also don't forget that pilot strength is part of ergonomics and the strength required is quoted in an Indian study here
Indian Journal of Aerospace Medicine
SPECIAL ISSUE 2, 1995
ERGONOMIC FACTORS DURING SPIN RECOVERY IN HJT – 16 TRAINER
WG CDR NN AGGARWAL, SQN LDR VV JOSHI
Spin manoeuvre familiarization is an essential part of flying training syllabus and requires
simultaneous two-handed operation in recovery of aircraft (ac). Amongst trainer ac in IAF, spin
recovery problems were perceived more HJT-16 (Kiran). An ergonomic laboratory study involving
10 experienced male fighter pilots in applicable flying clothing revealed that the overall forces
control column were within tolerance limits of single hand operations, the second hand guidance
was required for better precision. The ‘reach envelope studied’ in harness tight condition for
maximum forward operation of control column with permissible shoulder movements and without
shoulder movements showed mean angular motion difference at the control column 4.320 0±1.26 0
The mean difference between the forward movement of hands in two study protocols involving one hand and simultaneous two-hand operation was 1.81 0± 0.86 0
. The observed differences are statistically significant (p<0.001) influencing reach compromises under static and dynamic flying conditions of spin under and geometrical variations in elbow-wrist and shoulder-arm complex of individual crew and in woman pilots who generally have shorter limb parameters compared to their male counterparts.
The paper discusses various spin related ergonomic problems considering anthropometric and cockpit design factors.