As per their analysis, Brooks et al. surmised that survival after crash in water depends upon “amount of warning time, rapidity of sinking and inversion” . An advise worth following by all helicopter operators, based on this study, is that while flying over water, all occupants in helicopter must don their mae west or persoanl floatation devices [http://en.wikipedia.org/wiki/Personal_flotation_device] through out the sortie duration rather than attempting to retrieve it from the aircraft which reduces chances of survival in case of crash into water. Their recommendations for safety for helicopter operations over water were as following :-
- Mandatory training for crew and passengers in underwater escape training simulator,
- Wear appropriate safety equipment through out the flight,
- Proper preflight briefing of all, passengers included,
- Ensure secure stowage of all equipment and personal items in flight deck and cabin,
- Wearing seat harnesses tight and locked during the flight
A practical advise offered by the authors, besides mental and physical preparation for escape from a sinking helicopter, is that crew and passengers must:-
- Adopt a crash position,
- Take a good breath prior to immersion, and
- Hold that breath until reaching the surface.
They further stress that in case of call from pilots about imminent ditching or while in an accident, the crew and passengers must follow the following :-
- Anticipation and preparation for sudden immersion and inversion in water,
- “Check escape path for both primary and secondary exits”,
- Ensure physical reference to the escape exit has been made,
- Check the survival suit, if worn, for watertight integrity,
- Lifejacket, if worn – check the toggle, but it should be inflated only after exiting the helicopter.
Briefly, various factors, other than helicopter model and area of operations, determining survivability are restraint systems, structural stiffness, landing gear, fuel system and helmets (19, 20). But that is a topic for discussion at a later date…
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13. Brooks CJ, MacDonald CV, Donati L, Taber MJ. Civilian helicopter accidents into water: analysis of 46 cases, 1979-2006. Aviat Space Environ Med 2008; 79: 935-40
14. Rice E, Greear J. Underwater escape from helicopters. Paper presented at SAFE Conference; October, 1973; Phoenix,AZ. Creswell, 1973. [As quoted in Johnson NB, Robertson DSH. Aircraft Crash Survival Design Guide Vol. V – Aircraft Postcrash Survival. Report No. USAAVSCOM TR 89-D-22E. 1989 Section 6.2.2. (Page 142)]
15. Clifford WS. Helicopter crashworthiness: study 1 — A review of UK military and world civil helicopter water impacts over the period 1971-1992. Study 2 — an analysis of the response of helicopter structures to water impact. London, UK: Civil Aviation Authority; 1996. Report No. 96005. [As quoted in Brooks CJ, MacDonald CV, Donati L, Taber MJ. Civilian helicopter accidents into water: analysis of 46 cases, 1979-2006. Aviat Space Environ Med 2008; 79: 935-40]
16. Vyrnwy-Jones P, Turner JCD. A review of Royal Navy helicopter accidents 1972-1984. Farnborough, Hampshire, UK: Royal Air Force Institute of Aviation Medicine; 1989. IAM Report No.648. [As quoted in Brooks CJ, MacDonald CV, Donati L, Taber MJ. Civilian helicopter accidents into water: analysis of 46 cases, 1979-2006. Aviat Space Environ Med 2008; 79: 935-40]
17. Glancy JJ, Desjardins SP. A survey of naval aircraft crash environments with emphasis on structural response. Dynamic Science; 1971; Phoenix, AZ. Arlington VA: Office of Naval Research;1971. Report No. 1500-71-43.
18. Chen CT, Muller M, Fogarty KM. Rotorcraft ditchings and water related impacts that occurred from 1982 to 1989 — phase 1. Pleasantville, NJ: Galaxy Scientifi c Corporation; 1993. Report No.: DOT/FAA/CT-92/13.
20. Shanahan DF, Shanahan MO. Injury in U.S. Army helicopter crashes October 1979-September 1985.J Trauma. 1989 Apr;29(4):415-22.
Acknowledgement Image courtesy Wikipedia