Emergency Evacuation on Land
Emergency Evacuation on Land
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Definition
Emergency Evacuation is the urgent abandonment of an aircraft utilising all useable exits.
Evacuation in progress from A310 which crash landed, 12 July 2000 - copyright Vienna Airport Press Department
Threats
Failure to evacuate the aircraft in a timely manner may lead to the death or injury of crew and passengers. Failure to evacuate an aircraft in an orderly and safe manner may also lead to injuries to passengers. This article provides an overview of the more common scenarios, certification requirements, crew response, aircraft equipment, and inherent risks of an evacuation. For a more complete treatise on the subject, refer to the Royal Aeronautical Society (RAeS) paper listed under Further Reading.
Defences
An inflight fire, smoke or fume emergency will be dealt with as aggressively as possible by the crew and, if appropriate, an immediate diversion to landing will be initiated. If the emergency is not secured, once on the ground, the most appropriate course of action is to remove the passengers and crew from the risk as a precautionary measure. Likewise, in the event of an uncontrolled engine or airframe fire during ground operations, an aircraft crash on a takeoff or landing, or any other situation that results in fire or structural failure, the best defence available is an immediate evacuation of the aircraft.
Typical Scenarios
- During the takeoff roll, the number two engine fire warning system is activated. The takeoff is rejected and the aircraft is stopped on the runway. Checklist items are carried out but the warnings persist and the air traffic control tower reports smoke and flames on the right wing of the aircraft. The remaining engine is shut down and an evacuation is initiated. Rescue and Fire Fighting Services (RFFS) arrive on scene within 3 minutes and extinguish the fire. Minor injuries are reported by some passengers as a result of the evacuation
- An inflight fire in a rear toilet fills the aircraft with smoke. An emergency is declared and, after some initial evaluation during which the situation worsens, the aircraft diverts to land at a nearby airport. RFFS are on scene and evacuation is initiated immediately after the aircraft comes to a stop on landing. Flashover occurs before the evacuation is complete resulting in the deaths of many of those on board.
Certification
As part of the certification process, aircraft manufacturers are required to demonstrate that an aircraft, in maximum density configuration, can be completely evacuated within 90 seconds using only half of the total number of emergency exits. Use of only half of the exits simulates the potential for failed evacuation devices or exits blocked due to fire or structural damage. Ninety seconds has been established as the maximum evacuation time because tests have shown that, in a post crash fire, conditions conducive to flashover are unlikely to occur within that time span. However, the experience of actual evacuations, especially unexpected ones from full aircraft where the abnormal situation occurs suddenly at or soon after landing, indicates that evacuation times usually exceed durations demonstrated for certification purposes.
- Video showing the emergency evacuation test for the Airbus A380 at Hamburg
- Video showing the certification trial for the Airbus A380 at Toulouse
- Video showing the Boeing 777 emergency evacuation test
Common Evacuations Issues
Common safety deficiencies during the evacuation process are often associated with communications, exit operation, passenger preparedness for evacuations, and the presence of fire, smoke, and toxic fumes.
Delays
As much as a minute can pass before the flight or cabin crew initiates the evacuation. This is a very long time for passengers to endure if it is obvious that an emergency situation exists. On the other hand, if the emergency is not obvious, passengers may revert to their routine and e.g. start opening the overhead bins to retrieve their luggage. This action will be very difficult to prevent when the cabin crewmembers are required to remain at their stations near the emergency exits.
Communication
In an emergency evacuation, effective communications among the crew members and with the passengers is essential for a timely, orderly, effective response. The communication could be hindered by
- Inoperative Public Address (PA) systems - The cabin crew and/or passengers are unable to hear the initial evacuation command and/or subsequent directions. PA systems could be rendered inoperable or unintentionally switched off during evacuations.
- Inadequate crew communication - Non-effective communication between the cabin and the flight deck could result in a significant delay of the evacuaion.
Exit and Slide Operation
Problems in operating emergency exits and deploying emergency slides delayed many evacuations, potentially compromising the success of the evacuation. Cabin crew or passengers could experience difficulty operating emergency exit doors.
Passenger Preparedness
Passengers' lack of preparedness to act appropriately, or adverse behaviour, during an evacuation is a serious issue during many evacuations. Passengers might not perceive the danger they are in and therefore could act in an inappropriate manner (e.g. being slow to respond to cabin crew instructions, looking for friends and relatives or even trying to open overhead compartment storage to retrieve luggage).
Fire, Smoke and Fumes
The presence of fire, smoke, and/or toxic fumes present the greatest risk to a successful evacuation by restricting visibility, limiting communications, reducing the number of available exits, affecting passenger behaviour, and decreasing occupants' mental and physical capacities. Fire, smoke, and/or toxic fumes are identified as a serious hazard during the evacuations.
For example, in the B732, Manchester UK, 1985 accident, the major cause of the fatalities was rapid incapacitation due to the inhalation of the dense toxic/irritant smoke atmosphere within the cabin.
Emergency Briefings
As part of their pre-departure duties, the Cabin Crew will provide a Safety Briefing to passengers which will include the emergency evacuation of the aircraft. This briefing will refer passengers to their individual Safety Briefing Cards but will always include pointing out exit locations and floor path lighting for particular use in poor visibility. The briefing will advise on the availability of evacuation slides at exits and may give instructions on how to open exits. Passengers seated in emergency exit rows at overwing exits where no cabin crew are located may be individually briefed on how to open these in the event of an emergency. If an airborne emergency occurs which makes an evacuation on landing likely, then the Cabin Crew will provide more detailed instructions if the time available permits.
The results of evacuation trials have shown that the opening of emergency doors by passengers was proven to be more successful when the passengers were familiarized with the instructions provided in the safety cards, or when a personal briefing was provided by a cabin crewmember.
Emergency Exits
Depending upon the aircraft, emergency exits can include normal boarding and service doors, overwing exits, and tailcone exits within the passenger cabin; and cockpit windows or hatches on the flight deck and in freight bays. These may be equipped with boarding stairs, evacuation slides or emergency egress ropes. For a more complete description of exit types, refer to section 7.2 of the Royal Aeronautical Society (RAeS) paper Emergency Evacuation of Commercial Passenger Aeroplanes.
Evacuation Slides
An evacuation slide is an inflatable device which facilitates the rapid evacuation of an aircraft. Slides are required on all passenger carrying aircraft where the door sill height (measured as the normal height above ground level) is such that able bodied passengers would be unable to jump or "step down" from the exit without a significant risk of injury. This has been interpreted in Regulatory requirements as meaning slides must be installed at all aircraft doors where the floor is 1.8 metres (6 feet) or more above the ground. Slides are also required on overwing exits when the height of the wing above the ground, with the flaps fully extended, exceeds the maximum certified distance or where an evacuation route ahead of the wing is intended. Some slides are also designed to serve as rafts when detached from the aircraft in the event of a landing on water.
In the case of over-wing exits, no slide is required providing the escape route utilises the flap surface and the height to the ground from the trailing edge of the flap is less than six feet.
Cabin Crew Duties
Evacuation is normally ordered by the Captain. However, if communication with the flight crew is not possible and the situation in the cabin is judged by the senior cabin crew member to be incompatible with any delay, then they are trained to make the evacuation order themselves once the aircraft has come to a complete stop. In these circumstances, they are responsible for assessing immediate danger such as external fire or engines still running before any exit is opened. Cabin crew supervising exits must also secure the exit until the slide (if the exit is so equipped) inflates and block the exit from use in the event of a slide malfunction. They are also expected to motivate passengers using appropriate shouted commands and if necessary, physical action, to exit quickly and to leave behind personal possessions, especially items in overhead lockers or under seats. Normally, the Cabin Crew will be the last to leave their exit; however, in practice they are trained to remain on board only to the point when they believe that by staying any longer they are putting their own lives at risk. Once they are out of the aircraft, they are trained to assist in moving passengers away from the aircraft to a position where they can be safely grouped together.
Accidents & Incidents
The Following is a list of events which have involved emergency aircraft evacuation:
On 2 October 2021, an Airbus A320neo ingested a large bird into its right engine (a Pratt & Whitney PW1100G) during takeoff at Atlantic City and a high speed rejected takeoff followed. When leaked fuel pooling within the engine cowling subsequently ignited, an on-runway emergency evacuation was completed with the fire service in attendance. The Investigation identified the ingested bird as a bald eagle with a mass above the applicable certification standard and the fuel leak a secondary consequence of a fan blade broken by bird impact. Engine component design improvements to address the fire risk following large bird ingestion are being developed.
On 6 December 2018, a Boeing 737-700 overran the 1,770 metre-long landing runway at destination by 45 metres after entering the EMAS. Normal visibility prevailed but heavy rain was falling and a 10 knot tailwind component existed. The event was attributed to the pilots’ continuation bias in the face of deteriorating conditions and a late touchdown on the relatively short runway. A lack of guidance from the operator on the need for pilots to re-assess the validity of landing data routinely obtained at the top of descent was identified.
On 25 December 2016, a type-experienced ATR72-600 Captain bounced the aircraft twice nose gear first whilst attempting a night landing at Semarang and during a third bounce on the right main gear only, it collapsed. The aircraft drifted right and after two further bounces began to decelerate and came to a stop. The Investigation found that after a normally-flown approach, the aircraft had not been flared and effective recovery action had not followed the bounce. It was concluded that the Captain had been subject to a visual illusion which had distorted his perception of height above the runway.
On 2 July 2017, the left engine of a Bombarier CRJ 700A exiting the runway after landing at Denver caught fire and continued burning after the aircraft had been stopped on the taxiway and the engine shut down. The Investigation found that the fuel supply to the fuel-operated engine performance valve had failed and the quantity of fuel which then leaked had overwhelmed the engine cowl drain capacity and ignited. A history of similar failures was found and this one resulted in the introduction of additional mandatory in-serviced checks pending the replacement of the valve concerned with an improved design.
On 15 December 2019, an Airbus A330-200 turned back to Sydney shortly after departure when a major hydraulic system leak was annunciated. The return was uneventful until engine shutdown after clearing the runway following which APU use for air conditioning was followed by a gradual build up of hydraulic haze and fumes which eventually prompted an emergency evacuation. The Investigation found that fluid leaking from ruptured rudder servo hose had entered the APU air intake. The resulting evacuation was found to have been somewhat disorganised with this being attributed mainly to a combination of inadequate cabin crew procedures and training.
On 5 August 2019, an Airbus A321 crew declared a MAYDAY immediately after clearing the landing runway at Valencia when a hold smoke warning was annunciated. An emergency evacuation was completed without injuries. This warning followed “white smoke” from the air conditioning system entering both the passenger cabin and flight deck in the four minutes before landing which had prompted the pilots to don oxygen masks. The Investigation found the white smoke was the direct consequence of an oil leak from the right engine as a result of the misalignment and breakage of a bearing and its associated hydraulic seal.
On 21 November 2019, with variable cross/tailwind components prevailing, a Boeing 737-800 went around from its first ILS approach to Odesa before successfully touching down from its second. It then initially veered left off the runway before regaining it after around 550 metres with two of the three landing gear legs collapsed. An emergency evacuation followed once stopped. The Investigation attributed the excursion to inappropriate directional control inputs just before but especially after touchdown, particularly a large and rapid nosewheel steering input at 130 knots which made a skid inevitable. Impact damage was also caused to runway and taxiway lighting.
On 15 August 2019, a Boeing 767-300 made a high speed rejected takeoff because of increasing noise from an unsecured flight deck sliding window. Whilst subsequently taxiing during the calculated brake cooling time, fire broke out in the left main gear bay and the aircraft was stopped and an emergency evacuation was carried out whilst the fire was being successfully extinguished. The Investigation did not identify any specific cause for the brake unit fires but noted that the reject had been called when 3 knots above V1 and that the maximum speed subsequently reached had been 14 knots above it.
On 2 February 2013, an ATR 72-500 bounced repeatedly when making a night landing at Rome Fiumicino which, in the presence of dual control inputs causing a pitch disconnect, resulted in complete detachment of the landing gear and a veer off before stopping. The accident was attributed to uncharacteristic mishandling by the type experienced Captain in the presence of ineffective crew resource management because of an extremely steep authority gradient resulting from a very significant difference in flight time on the aircraft type (9607 hours / 14 hours). The Investigation attributed an unacceptable delay in the rescue services’ response to managerial incompetence.
On 3 May 2019, a Boeing 737-800 significantly overran the wet landing runway at Jacksonville Naval Air Station at night when braking action was less than expected and ended up in shallow tidal water. The Investigation found that although the approach involved had been unstabilised and made with a significant tailwind and with only a single thrust reverser available, these factors had not been the cause of the overrun which was entirely attributable to attempting to complete a landing after touching down on a wet runway during heavy rain in conditions which then led to viscous aquaplaning.
Related Articles
- Passenger Cabin Fire
- Direct Emergency Communication
- Cabin Crew-Flight Crew Emergency Communication
- Post Crash Fires
- Emergency Evacuation on Water
- Aircraft Exit Injuries
Further Reading
- Emergency Evacuation of Commercial Passenger Aeroplanes, Second Edition 2020, Royal Aeronautical Society (RAeS) paper published in June 2020.
- CAP 1150 - Information Paper 04 Task and Resource Analysis- establishes justification as to the minimum number of qualified/competent personnel required to deliver an effective Airport Rescue and Fire fighting Service (RFFS) to deal with an aircraft incident/accident.
- CAP 699 - Framework for the competence of rescue and fire fighting service (RFFS) personnel, January 2017
- 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
