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!
There are two types of escape from an aircraft:-
- Unassisted Escape. This is an egress from an aircraft, affected without the use of any mechanical or ballistic aids, other than muscular power of the escaping pilot and the force of gravity. The maximum speed of the aircraft for unassisted safe escape is approximately 200 Knots. This may be necessitated in gliders, propeller driven trainer aircraft, helicopters or transport aircraft.
- Assisted Escape. At speeds more than 200 Knots it becomes necessary for the occupant to be propelled out of the aircraft, as in a combat aircraft, with the help of an ejection seat.
Unassisted Escape. This is defined as escape without any mechanical or ballistic assistance to push an aviator out of a crippled aircraft. In the days when the aircraft flew ‘low and slow’ it was customary in an emergency to put the aircraft down in any place, provided that there was a reasonably flat surface available. With increasing speed this method gave way to unassisted escape commonly known as bailing out of the aircraft. This is the method of escape from the basic flying trainers like Pushpak or Deepak (HPT-32) in India.There are various techniques for bailing out. This includes rolling the aircraft on its back and falling out or jumping out after stepping on wings (from the trailing edge) after bringing the aircraft in a straight and level attitude. More importantly, each aircraft has its own set of escape procedure to be followed by the pilot in an emergency necessitating escape. It is vital for the pilot to be aware about the procedures and limitations for bail out to ensure safe escape from an aircraft.
Assisted Escape. With increase in aircraft speed, it becomes impossible for a pilot to manually separate from the aircraft in an emergency because of high-pressure forces of wind blast (Q forces) or immobilization by ‘G’ forces during uncontrolled aircraft manoeuvres. It, therefore, necessitates, an assisted means of escape. The ejection seat provides the assistance to leave a disabled aircraft in case of an emergency. Most of the fighter aircraft have an open types of assisted escape system, except MiG 21 type 77, with its semi-capsular ejection system, and F-111 aircraft with its closed capsular ejection system.
- An Ejection Seat
- Biodynamics of Ejection
- Potential for Ejection Injuries
- Current Ejection Systems
- Human Factors in Delayed Ejection
1. Ernsting’s Aviation Medicine. Rainford DJ, Gradwell DP (Editors). 4th Edition. Hodder Arnold, London 2006.
2. Fundamentals of Aerospace Medicine. DeHart RL, Davis JR (Editors). 3rd Edition. Lippincott, Williams & Wilkins, Philadelphia 2002.
Acknowledgement Image courtesy Wikimedia Commons