Emergency Evacuation on Land

Emergency Evacuation on Land

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 firesmoke 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.

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 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.

On 27 December 2016, the crew of a Boeing 737-800 taking off from Goa at night lost control shortly after setting takeoff thrust following which the aircraft almost immediately began to drift right and off the runway. It then continued at speed over rough ground for almost 300 metres before eventually stopping after which a MAYDAY call was followed by an emergency evacuation. The Investigation found that the Captain had increased thrust to takeoff without first ensuring that both engines were stabilised and then attempted to correct the drift by left rudder and brake rather than rejecting the takeoff.

On 5 August 2019, a Cessa 560XLS touched down in runway undershot at Aarhus whilst making a night ILS approach there and damage sustained when it collided with parts of the ILS LOC antenna caused a fuel leak which after injury-free evacuation of the occupants then ignited destroying most of the aircraft. The Investigation attributed the accident to the Captain’s decision to intentionally fly below the ILS glideslope in order to touch down at the threshold and to the disabling of the EGWPS alerting function in the presence of a steep authority gradient, procedural non-compliance and poor CRM.

On 1 March 2019, an Airbus A320 left engine suffered a contained failure soon after takeoff thrust was set for a night departure from London Stansted but despite the absence of an instruction to cabin crew to begin an evacuation, they did so anyway just before the aircraft was going to be taxied clear of the runway with the Captain only aware when passengers were seen outside the aircraft. The Investigation found that an evacuation had been ordered by the senior member of the cabin crew after she was “overwhelmed” by the situation and believed her team members were “scared”.

On 28 February 2019, an Airbus A320 abandoned takeoff from Exeter when fight deck fumes/smoke accompanied thrust applied against the brakes. When informed of similar conditions in the cabin, the Captain ordered an emergency evacuation. Some passengers using the overwing exits re-entered the cabin after becoming confused as to how to leave the wing. The Investigation attributed the fumes to an incorrectly-performed engine compressor wash arising in a context of poorly-managed maintenance and concluded that guidance on overwing exit use had been inadequate and that the 1.8 metre certification height limit for exits without evacuation slides should be reduced.

On 3 August 2018, smoke appeared and began to intensify in the passenger cabin but not the flight deck of an Airbus A319 taxiing for departure at Helsinki. Cabin crew notified the Captain who stopped the aircraft and sanctioned an emergency evacuation. This then commenced whilst the engines were still running and inadequate instructions to passengers resulted in a completely disorderly evacuation. The Investigation attributed this to inadequate crew procedures which only envisaged an evacuation ordered by the Captain for reasons they were directly aware of and not a situation where the evacuation need was only obvious in the cabin.

On 10 May 2019, a Bombardier DHC8-300 taxiing in at Toronto at night was hit by a fuel tanker travelling at “approximately 25 mph” which failed to give way where a designated roadway crossed a taxiway causing direct crew and indirect passenger injuries and substantial damage. The Investigation attributed the collision to the vehicle driver’s limited field of vision in the direction of the aircraft coming and lack of action to compensate for this, noting the need for more effective driver vigilance with respect to aircraft right of way rules when crossing taxiways. The aircraft was declared beyond economic repair.

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.

On 6 July 2013, an Asiana Boeing 777-200 descended below the visual glidepath on short finals at San Francisco after the pilots failed to notice that their actions had reduced thrust to idle. Upon late recognition that the aircraft was too low and slow, they were unable to recover before the aircraft hit the sea wall and the tail detached. Control was lost and the fuselage eventually hit the ground. A few occupants were ejected at impact but most managed to evacuate subsequently and before fire took hold. The Probable Cause of the accident was determined to be the mismanagement of the aircraft by the pilots.

On 19 October 2012, a Jet2-operated Boeing 737-800 departing Glasgow made a high speed rejected take off when a strange smell became apparent in the flight deck and the senior cabin crew reported what appeared to be smoke in the cabin. The subsequent emergency evacuation resulted in one serious passenger injury. The Investigation was unable to conclusively identify a cause of the smoke and the also- detected burning smells but excess moisture in the air conditioning system was considered likely to have been a factor and the Operator subsequently made changes to its maintenance procedures.

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