Difference between revisions of "Aircraft Exit Injuries"
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This article describes the injuries that can be caused during an emergency evacuation and gives some background information on evacuation procedures and legislative requirements applicable to evacuation slides.
Emergency evacuation of commercial aircrafts can occur under a number of circumstances such as:
- Survivable crash scenarios
- Precautionary emergency landings (e.g. smoke in the cabin)
- Actual emergencies (e.g. confirmed fire, fuel leak, engine fire, damage to aircraft)
- Un-commanded evacuations (i.e. on passengers' initiative)
- Security related evacuations (e.g. due to bomb threat)
Evacuation slides play an important part during the process and must:
- Automatically deploy and erect in 6 seconds
- Be such length that after full deployment, the lower end is self-supporting on the ground and provides safe evacuation of occupants to the ground after collapse of one or more legs of the landing gear
- Have the capability, in 25 knot winds directed from the most critical angle, to deploy and, with the assistance of only one person, to remain usable after full deployment to evacuate occupants safely to the ground.
In addition, there must be approved means to assist passengers in descending to the ground from an exit that is higher than 6 feet from the ground. For overwing exits, this height can be measured with the flaps in either a takeoff or landing condition, whichever is higher.
The FAA may require airplane manufacturers to perform full-scale evacuation demonstrations in order to acquire type certification for new airplanes, and also for derivative models of currently certificated airplanes when the cabin configuration is unique or when a significant number of passenger seats have been added. A full-scale demonstration is a simulated emergency evacuation in which a full complement of passengers deplane through half of the required emergency exits, under dark-of-night conditions. A trained crew directs the evacuation, and the passengers are required to meet certain age/gender specifications. In order for manufacturers to pass the full-scale demonstrations, all passengers and crew must evacuate the aircraft and be on the ground in 90 seconds or less.
Injuries during Evacuation
More than 80% of reported injuries due to use of slides during emergency evacuation have been minor injuries. While relatively rare, the most serious evacuation-associated injuries were the result of jumping out of exits or off of wings.
Predominant causes of injuries are:
- Friction from slide surface
- Impact with the ground at the bottom of the slide
- Falling forward onto the pavement after reaching bottom of the slide
- Assisting other passengers with exiting the slide at the bottom
- Anxiety from evacuation
Typical minor Injuries
- Scrapes from slides
Typical serious Injuries
- Fractured ankle
- Broken leg
- Major Bruises
Other Issues and Considerations
- Lack of data. Slide deployment events are often not documented well and most are not investigated. Therefore, research on the subject may be somewhat inconclusive.
- Uncooperative behaviours, such as pushing, climbing seats, and disputes among passengers may be observed during an evacuation. Although such cases may include flames or substantial airplane damage, the severity of an event is not necessarily indicative of competitive actions.
- Cabin re-entry. In some cases the passengers leave the aircraft via the overwing exits only to return to the cabin shortly afterwards. This is often the case when the flaps are not at the appropriate position to assist in passengers in their descendind to the ground. People are usually reluctant to jump from the wings. As a result, evacuation is prolonged.
- Full-scale demonstration risks. While these are an approved (and effective) method to determine whether safe evacuation is achievable, there is a risk of injury in the process.
Accidents and Incidents
- A320, Halifax NS Canada, 2015 (On 29 March 2015, an Airbus A320 crew mismanaged the descent during a night non-precision approach at Halifax and continued below MDA without the mandatory autopilot disconnection until, with inadequate visual reference, the aircraft impacted terrain and obstructions 225 metres short of the runway. The aircraft was destroyed but there were no fatalities. The Investigation found that the crew did not monitor their descent against the required vertical profile, as there was no SOP requiring them to do so, and did not recognise in time that a go around was appropriate.)
- A333, Kathmandu Nepal, 2015 (On 4 March 2015, the crew of a Turkish Airlines A333 continued an automatic non precision RNAV approach below the prescribed minimum descent altitude without having obtained any element of visual reference and when this was acquired a few seconds before the attempted landing, the aircraft was not aligned with the runway centreline and during a 2.7g low-pitch landing, the left main gear touched down on the grass. The aircraft then left the runway completely before stopping with a collapsed nose gear and sufficient damage to be assessed a hull loss. None of 235 occupants sustained serious injury.)
- A333, en-route, near Bournemouth UK, 2012 (On 16 April 2012, a Virgin Atlantic A330-300 made an air turnback to London Gatwick after repetitive hold smoke detector warnings began to occur during the climb. Continuing uncertainty about whether the warnings, which continued after landing, were false led to the decision to order an emergency evacuation on the runway. Subsequent investigation found that the smoke warnings had all been false and had mainly come from one faulty detector. It also found that aspects of the way the evacuation had taken place had indicated where there were opportunities to try and improve passenger behaviour.)
- B733, Nashville TN USA, 2015 (On 15 December 2015, a Boeing 737-300 crew inadvertently taxied their aircraft off the side of the taxiway into a ditch whilst en route to the gate after landing at Nashville in normal night visibility. Substantial damage was caused to the aircraft after collapse of the nose landing gear and some passengers sustained minor injuries during a subsequent cabin crew-initiated evacuation. The Investigation found that taxiing had continued when it became difficult to see the taxiway ahead in the presence of apron lighting glare after all centreline and edge lighting in that area had been inadvertently switched off by ATC.)
- B738, Djalaluddin Indonesia, 2013 (On 6 August 2013, a Boeing 737-800 encountered cows ahead on the runway after landing normally in daylight following an uneventful approach and was unable to avoid colliding with them at high speed and as a result departed the runway to the left. Parts of the airport perimeter fencing were found to have been either missing or inadequately maintained for a significant period prior to the accident despite the existence of an airport bird and animal hazard management plan. Corrective action was taken following the accident.)
- B752, London Gatwick, 2013 (An announcement by the Captain of a fully-boarded Boeing 757-200 about to depart which was intended to initiate a Precautionary Rapid Disembarkation due to smoke from a hydraulic leak was confusing and a partial emergency evacuation followed. The Investigation found that Cabin Crew only knew of this via the announcement and noted subsequent replacement of the applicable procedures by an improved version, although this was still considered to lack resilience in one respect. The event was considered to have illustrated the importance of having cabin crew close to doors when passengers are on board aircraft on the ground.)
- Emergency Evacuation of Commercial Passenger Aeroplanes, Royal Aeronautical Society (RAeS) paper published in May 2018.
- A Safety Study of evacuations of large passenger-carrying aircraft, TSB Canada, October 2013.
- Passenger Behavior during Aircraft Evacuations, an article in the December 2017 issue of "The Investigator" magazine
- Safety study: Emergency Evacuation of Commercial Airplanes, by NTSB, 2000