If you wish to contribute or participate in the discussions about articles you are invited to join SKYbrary as a registered user

 Actions

Difference between revisions of "Post Crash Fires"

From SKYbrary Wiki

Line 14: Line 14:
  
 
==Description==
 
==Description==
In the event of an impact with the ground or an obstacle, which results in structural damage to an aircraft, a fuel and/or oil fed fire can start if [[Ignition of Fuels|fuel]] comes into contact with hot surfaces. Equally, if flammable material, being carried as [[Dangerous Goods|dangerous goods]] on a  Civil aircraft or as cargo by a [[State Aircraft|military aircraft]], is damaged or the containment compromised, it may ignite as a consequence of impact, contact with hot surfaces or, in the case of spillage of unstable chemicals, the atmosphere.
+
In the event of an impact with the ground or an obstacle, which results in structural damage to an aircraft, a fuel and/or oil fed fire can start if [[Ignition of Fuels|fuel]] comes into contact with ignition sources. Equally, if flammable material, being carried as [[Dangerous Goods|dangerous goods]] on a  Civil aircraft or as cargo by a [[State Aircraft|military aircraft]], is damaged or the containment compromised, it may ignite as a consequence of impact, contact with hot surfaces or, in the case of spillage of unstable chemicals, the atmosphere.
  
 
Fire can spread quickly to the fuselage and through the cabin generating heat, [[Smoke|smoke]], and toxic decomposition products. If the temperature of trapped [[Smoke|smoke]] and gasses reaches the [[Auto-ignition Temperature|auto-ignition temperature]], [[Flashover|flashover]] will occur and an aircraft fuselage can be rapidly engulfed by flames.
 
Fire can spread quickly to the fuselage and through the cabin generating heat, [[Smoke|smoke]], and toxic decomposition products. If the temperature of trapped [[Smoke|smoke]] and gasses reaches the [[Auto-ignition Temperature|auto-ignition temperature]], [[Flashover|flashover]] will occur and an aircraft fuselage can be rapidly engulfed by flames.

Revision as of 18:09, 6 December 2018

Article Information
Category: Fire Smoke and Fumes Fire Smoke and Fumes
Content source: SKYbrary About SKYbrary
Content control: SKYbrary About SKYbrary

POST IMPACT FIRE

Definition

Post Crash Fires are fires which occur after an aircraft has crash landed or has impacted obstacles or other aircraft during ground movement, runway incursion, or runway excursion.

Description

In the event of an impact with the ground or an obstacle, which results in structural damage to an aircraft, a fuel and/or oil fed fire can start if fuel comes into contact with ignition sources. Equally, if flammable material, being carried as dangerous goods on a Civil aircraft or as cargo by a military aircraft, is damaged or the containment compromised, it may ignite as a consequence of impact, contact with hot surfaces or, in the case of spillage of unstable chemicals, the atmosphere.

Fire can spread quickly to the fuselage and through the cabin generating heat, smoke, and toxic decomposition products. If the temperature of trapped smoke and gasses reaches the auto-ignition temperature, flashover will occur and an aircraft fuselage can be rapidly engulfed by flames.

Effects

Depending upon the severity of the crash, and any resulting fire, the effect on the aircraft can vary from minor damage to total hull loss. Similarly, the potential casualty consequence of a crash/fire event ranges from no injuries to the loss of life of all on board. Collateral damage and casualties are possible dependent upon the location of the crash.

For aircraft with a maximum certified take-off weight of 5700 kilograms or less, post-impact fire contributes significantly to injuries and fatalities in accidents that are otherwise potentially survivable.

Defences

  • Aircraft Design. Aircraft structures and fuel systems can be designed to minimise the quantity of fuel spillage
  • Fuel - Virtually all large passenger aircraft burn jet fuel and not AVGAS. The much higher flashpoint of jet fuel reduces the potential for a post crash fire.

Solutions

  • Preparation of the aircraft - where the crash landing is anticipated, for example if an off-field landing is necessary or the aircraft has a landing gear malfunction, then there are several things that can be done to reduce the probability and severity of a fire:
    • Dump Fuel - if time and aircraft design allow, dump to reduce the amount of fuel and improve the handling of the aircraft. For aircraft not fitted with Fuel Dump capability, the aircraft can loiter in the vicinity of the landing airfield to burn gas. Note that, in the case of an onboard fire, smoke, or fumes, any delay to landing the aircraft, inclusive of dumping fuel, should not be considered.
    • Isolate fuel systems - close crossfeed valves.
    • Cabin - Prepare the cabin for emergency landing.
    • Cargo - Jettison flammable cargo if possible and practical.
  • Aircraft Evacuation - Expeditious emergency evacuation of the aircraft will minimise the loss of life in the event of a post crash fire. Consequently, robust training of the cabin crew in evacuation procedures is essential.
  • Engine Shutdown & Aircraft Systems - To minimize the potential for injury during the evacuation, the flight deck crew will take all necessary actions to shut down and, using fire handles, condition levers, or fire push button (depending on aircraft type) isolate the aircraft engines. Depending upon the degree of damage to the aircraft, this may not always be possible.
  • Rescue and Fire Fighting Services - Rescue and Fire Fighting Services (RFFS) are instrumental in saving lives and minimizing the damage from a post crash fire. If the crash occurs within the airfield boundaries, the initial RFFS response units will be on site within a very short period of time; often less than a minute. Response to an off airfield crash may take considerably longer due to the time it may take to locate the crash and to the accessibility of crash site.

Contributing Factors

Large amounts of fuel can be carried by modern aircraft and an aircraft crash has the potential to rupture the fuel tanks. Should the spilling fuel be exposed to a spark or open flame a fire may occur. This is particularly true of fuels with low flashpoints such as AVGAS. While jet fuels have a higher flashpoint and are less susceptible to sparks, exposing them to operating engines or to hot engine components may raise the temperature of the fuel to its auto-ignition point and a fire will result.

Accidents and Incidents

A selection of incidents from the SKYbrary database related to Post Crash Fire:

  • B190, vicinity Bebi south eastern Nigeria, 2008 (On 15 March 2008, a Beech 1900D on a non-revenue positioning flight to a private airstrip in mountainous terrain flown by an inadequately-briefed crew without sufficient guidance or previous relevant experience impacted terrain under power whilst trying to locate the destination visually after failing to respond to a series of GPWS Alerts and a final PULL UP Warning. Whilst attributing the accident to the crew, the Investigation also found a range of contributory deficiencies in respect of the Operator, official charting and ATS provision and additional deficiencies in the conduct of the unsuccessful SAR activity after the aircraft became overdue.)
  • AT43, Madang Papua New Guinea, 2013 (On 19 October 2013, an ATR42 freighter departing Madang had to reject its takeoff when it was impossible to rotate and it ended up semi-submerged in a shallow creek beyond the airfield perimeter. The Investigation found that loading had been contrary to instructions and the aircraft had a centre of gravity outside the permitted range and was overweight. This was attributed to the aircraft operator’s lack of adequate procedures for acceptance and loading of cargo. A lack of appreciation by all parties of the need to effectively mitigate runway overrun risk in the absence of a RESA was also highlighted.)
  • B462, Stord Norway, 2006 (On 10 October 2006, a BAE Systems 146-200 being operated by Danish airline Atlantic Airways on a passenger flight from Sola to Stord overran the end of runway 33 at destination at a slow speed in normal visibility at dawn (but just prior to the accepted definition of daylight) before plunging down a steep slope sustaining severe damage and catching fire immediately it had come to rest. The rapid spread of the fire and difficulties in evacuation resulted in the death of four of the 16 occupants and serious injury to six others. The aircraft was completely destroyed.)
  • B734, Yogyakarta Indonesia, 2007 (On 7 March 2007, a Boeing 737-400 being operated by Garuda landed on a scheduled passenger flight from Jakarta to Yogyakarta overran the end of the destination runway at speed in normal daylight visibility after a late and high speed landing attempt ending up 252 metres beyond the end of the runway surface in a rice paddy field. There was a severe and prolonged fire which destroyed the aircraft (see the illustration below taken from the Investigation Report) and 21 of the 140 occupants were killed, 12 seriously injured, 100 suffered minor injuries and 7 were uninjured.)
  • C500, vicinity Biggin Hill UK, 2008 (On 30 March 2008, a privately operated Cessna Citation 500 which had just taken off from Biggin Hill UK for Pau, France in day VMC reported ‘engine vibration’. Whilst positioning for a return to land, the aircraft descended and the pilots reported a major power problem just before it struck the side of a house killing all five occupants and destroying the house and adjacent property in the intense fire which followed.)

... further results


Related Articles

Further Reading