Emergency Evacuation is the urgent abandonment of an aircraft utilising all useable exits.
Evacuation and Crew Training
The potential for survival of an emergency which results in a ditching depends largely on the type and effectiveness of training the flight crew and the cabin crew had received beforehand. Adequate training is required to ensure that personnel respond appropriately to the emergency and to maximize the likelihood of a successful ditching, evacuation and subsequent survival.
Evacuations can be categorized as one of two main types:
- Planned: Those for which sufficient time exists to brief the passengers and crew and prepare the cabin
- Unplanned: Those for which there is insufficient time to brief the passengers and crew
General Emergency Evacuation Guidelines
The following general emergency evacuation guidelines for passenger and crew emergency egress are valid for both evacuations on land and on water:
- In a ditching situation, more than one impact should be expected
- Evacuation should not be initiated until the aircraft has come to a complete stop
- The engines must be shut down before opening door directly forward or aft of an engine
- Cabin crewmembers should begin evacuation immediately upon signal from the flight deck crew
- Cabin crew should follow any additional instructions the flight deck crew may give
- If there is an emergency that the flight crew may not be aware of and time permits, the cabin crew should notify the flight deck prior to initiating an evacuation; if time does not permit, the notification of the flight deck should be done simultaneously upon commencement of evacuation
- Cabin crew should make an independent decision to initiate an evacuation when there is severe structural damage, a life-threatening situation (fire, smoke, impact forces, ditching) or abnormal aircraft attitude exists and there is no response from the flight deck crew
- If one cabin crewmember initiates an evacuation, all cabin crewmembers should follow evacuation procedures immediately
- When a crewmember’s life is directly and imminently in danger, the cabin crewmember’s personal safety should always take priority
Preparation for an Evacuation on Water
In a planned ditching situation, the cabin, passengers and cabin crew preparation involve the same procedures as with an emergency landing, except for the following:
- Passengers should be informed about the ditching procedure
- Cabin crew should demonstrate the donning of life vests, the brace positions, point out the exits, and finally, show the safety instruction cards
- Cabin crew should make sure that passengers have correctly donned life vests (including infant’s life vests), and understand how and when to inflate them
- Passengers should be reminded to inflate life vests only as they leave the aircraft
- Crewmember life vests should be a different colour than the passengers’ life vest (e.g., bright orange). Life vests should have lights (e.g., water activated).
The following are suggested items for the crew to consider when preparing to evacuate the aircraft following a water ditching:
- Determine the water level outside the aircraft
- Determine the water level inside the aircraft and the rate of change
- If water level is above the door sill, the exit is unusable In many cases, the slide/life rafts can be detached and moved to a useable exit
- Some exits may be anticipated to be unusable due to the expected aircraft attitude in the water. This is often the case for the rear exits, especially in the case of an aircraft with rear mounted engines
- Prior to transferring slides/life rafts to useable exits, ensure all passengers are evacuated (into the water, if necessary)
- Deploy non door mounted flotation devices from the aft over wing exit as applicable to the aircraft type
- Cabin Crew should ensure that passenger raft count does not exceed recommended raft capacity
- Passengers should board the raft and sit on alternating sides
- Family members should be reseated together in the same life raft if possible
- Slide/Life rafts are detached by cutting the lifeline or pulling the disengage handle; follow instructions from the raft manual
- Attempt to assign crewmember(s) to each raft to establish command
- Where possible, group the rafts together
- Keep groups together and away from the aircraft, spilt fuel and debris.
Factors Affecting Survivors After Evacuation on Water
It is essential that in order to survive a water ditching and be rescued successfully, some basic factors must be taken into consideration. These factors are:
- Protection: The most pressing action should be protection from the adverse effects of the environment (i.e., water, the chilling effect of wind on wet clothing, extremes of temperature, etc.)
- Location: Have all signaling equipment ready
- Water: Take as much water as possible and plan on rationing it
- Food: Check on supplies available; if the quantity of the water supply is in question, decrease the food ration; the quantity of food and water must vary in direct proportion.
Duration of Exposure
When a person suddenly comes into contact with extremely cold water, they experience a cold shock response. This phenomenon is similar to jumping into a freezing swimming pool on a hot summer day. Immediately, the person will hyperventilate and take uncontrollable, deep and fast breaths for the next one to three minutes. If a person goes underwater in this state, he/she could swallow water and drown. However, the cold shock response is short-lived and the associated risk subsides fairly quickly.
Survivors of a ditching will not only be unprepared for the sudden exposure to low water temperatures, they are also likely to experience increased body-cooling rates due to the evaporating fuel from the aircraft wreckage. Survivors are vulnerable to hypothermia which may set in when the core body temperature drops below the minimum temperature required for normal metabolism and bodily functions at approximately 35°C.
Ditching is often a high-impact event, which is likely to result in the break-up of the fuselage. Spilt fuel could possibly be ignited, leading to a post-impact fire. Even if ignition sources were suppressed by the waters, the inhalation and ingestion of fuel vapors can pose severe health risks to the survivors.
Examples of Fixed Wing aircraft Ditchings
The Following are events, which have involved emergency aircraft evacuation on water:
- A320, vicinity LaGuardia New York USA, 2009 - On 15 January 2009, a United Airlines Airbus A320-200 approaching 3000 feet agl in day VMC following take-off from New York La Guardia experienced an almost complete loss of thrust in both engines after encountering a flock of Canada Geese . In the absence of viable alternatives, the aircraft was successfully ditched in the Hudson River about. Of the 150 occupants, one flight attendant and four passengers were seriously injured and the aircraft was substantially damaged. The subsequent investigation led to the issue of 35 Safety Recommendations mainly relating to ditching, bird strike and low level dual engine failure.
- AT72, en-route, Mediterranean Sea near Palermo Italy, 2005 - On 6 August 2005, a Tuninter ATR 72-200 was ditched near Palermo after fuel was unexpectedly exhausted en route. The aircraft broke into three sections on impact and 16 of the 39 occupants died. The Investigation found that insufficient fuel had been loaded prior to flight because the flight crew relied exclusively upon the fuel quantity gauges which had been fitted incorrectly by maintenance personnel. It was also found that the pilots had not fully followed appropriate procedures after the engine run down and that if they had, it was at least possible that a ditching could have been avoided.
- WW24, vicinity Norfolk Island South Pacific, 2009 - On 18 November 2009, an IAI Westwind on an aeromedical flight failed to achieve a landing at Norfolk Island after four night IMC approaches in poor weather and was then intentionally ditched offshore due to having insufficient fuel then remaining to reach the nearest alternate. The fuselage broke in two after the ditching but all six occupants escaped from the rapidly flooded fuselage before it sank and were eventually located and rescued. The situation which led to the ditching was attributed by the subsequent investigation to poor in flight decision making possibly affected by fatigue.
- NIM, manoeuvring, northern North Sea UK, 1995 - On 16 May 1995, an RAF Nimrod maritime patrol aircraft on a day VMC airworthiness function flight off the north east coast of Scotland following major maintenance suffered an uncontrollable fire in one of its four engines which subsequently spread to the adjacent engine and threatened the structural integrity and consequently the likely controllability of the aircraft. A successful ditching in the sea was subsequently carried out 3 nm from RAF Lossiemouth. All occupants successfully evacuated the aircraft, with three sustaining minor injuries.
Examples of Rotary Wing aircraft Ditchings
- EC25, en-route, 20nm east of Aberdeen UK, 2012 - On 10 May 2012, the crew of a Eurocopter EC225 LP on a flight from Aberdeen to an offshore platform received an indication that the main gearbox (MGB) lubrication system had failed. Shortly after selecting the emergency lubrication system, that also indicated failure and the crew responded in accordance with the QRH drill to “land immediately” by carrying out a successful controlled ditching.
- EC25, en-route, 32nm southwest of Sumburgh UK, 2012 - On 22 October 2012, the crew of a Eurocopter EC225 LP on a flight from Aberdeen to an offshore platform received an indication that the main gearbox (MGB) lubrication system had failed. The crew responded in accordance with the QRH drill by carrying out a successful ditching procedure.
- AS3B, vicinity Den Helder Netherlands, 2006 - On 21 November 2006, the crew of a Bristow Eurocopter AS332 L2 making an unscheduled passenger flight from an offshore platform to Den Helder in night VMC decided to ditch their aircraft after apparent malfunction of an engine and the flight controls were perceived as rendering it unable to safely complete the flight. Despite extensive investigation, no technical fault which would have rendered it unflyable could be confirmed.
- Emergency Evacuation of Commercial Passenger Aeroplanes, Second Edition 2020, Royal Aeronautical Society (RAeS) paper published in June 2020.
- Cabin Safety Compendium, AOSPWG/GAIN, Issue 1 December 2001
- A Safety Study of evacuations of large passenger-carrying aircraft, TSB Canada, October 2013
- TP13822E - Survival in Cold Waters: Staying Alive, C. Brooks, TSB Canada, January 2003
- Life Rafts and Lifeboats: An Overview of Progress to Date, Chapter 9A of NATO RTO-AG-HFM-152 ‘Survival at Sea for Mariners, Aviators and Search and Rescue Personnel’, by C. Brooks, February 2008
- CAP 699 - Framework for the competence of rescue and fire fighting service (RFFS) personnel, January 2017
- Passenger Behavior during Aircraft Evacuations, an article in the December 2017 issue of "The Investigator" magazine
Editor's Notes <references>
- ^ Life jackets/vests are used for floatation in a ditching situation. They can be found in proximity to, usually under, each cabin seat. Passengers' life jackets are normally yellow in color and a different color (normally red) for the crew. Life Jackets contain one, or more often two, buoyancy chambers that can be inflated by either CO2 cartridge(s) or by oral inflation. A water activated light and a whistle are incorporated for the purpose of attracting rescuers' attention.