In-Flight Fires | Crew Actions are the Primary Line of Defense

In-Flight Fires | Crew Actions are the Primary Line of Defense

cabin  Fires

 

In-flight fire is one of the most serious threats to flight safety today. In such an occurrence, cabin crew and flight crew actions - CRM- are the primary line of defense. They are well trained to deal with in-flight fire threats.

Cabin safety contributes to the prevention of accidents and incidents, the protection of the aircraft’s occupants, through proactive safety management, including hazard identification and safety risk management, and the increase of survivability in the event of an emergency.

In 2005 a statistical analysis of commercial jet aircraft accident data shows that in-flight fire was responsible for the fourth-highest number of onboard fatalities and was the seventh most frequent cause of accidents.

(Boeing, 2005).

During the In-flight fire, time in minutes will help cabin crew and flight crew perform a successful landing and evacuation. According to the FAA, in the event of an in-flight fire, “...delaying the aircraft’s descent by only two minutes is likely to make the difference between a successful landing and evacuation, and a complete loss of the aircraft and its occupants.”

(Federal Aviation Administration, 2004).

 

The Extent of the Risk - In-flight fire

One example is an uncontrolled fire that caused the crash of a Trans World Airline Lockheed Constellation on 11 July 1946, near Reading, Pennsylvania. Soon after departure on this training flight, the crew began to smell burning insulation. 

The flight engineer opened the flight deck door and reported to the Captain: “The whole cabin is on fire.”

The flight crew attempted to fight the fire without success. Dense smoke streamed into the flight deck and filled it, obscuring the instruments. 

The instructor captain opened the window to find the airport but was unable to maintain control. The airplane crashed killing everyone on board, except the instructor captain.

The accident report determined that: “The reason for the loss of control of the aircraft immediately before impact and therefore the most immediate cause of the accident was the inability of the pilots to maintain adequate control because of the denseness of the smoke within the crew compartment.”

(Civil Aeronautics Board, 1946)

 

Fire Retardant Materials

According to ICAO Safety Report 2019 Edition, since 1985 an Improved test standard for large surface area panels (e.g. ceilings, walls, galleys, overhead bins, and partitions) has been implemented to delay the onset of a cabin flashover (flash fire) event.

The improved standards give passengers and crew members more time to evacuate the aircraft after an accident. This improvement in cabin material flammability was demonstrated to delay flashover in the cabin.

New cushion material provides 40 to 60 seconds of additional time for aircraft evacuation compared to the previously used cushions.

(ICAO Safety Report 2019 Edition)

 

Causes of In-Flight Fires

There are many subtle causes of in-flight fires.

A. Wiring failures.

A majority of hidden in-flight fires are the result of electrical arcs along with wire bundles. In most cases, the electrical arc acts as the initiating event, igniting other surrounding materials. 

The surface of insulation materials is often a conveyer of these initiating events, as contamination from spillage, accumulated dirt/dust, lubrication or corrosion inhibitors on these surfaces can promote flame spread (uncontaminated insulation materials are generally very fire-resistant). 

In other instances, the resetting of a tripped circuit breaker can overheat wiring, ultimately leading to failure and arcing, causing the same chain of events.

 b. Electrical Component Failures.

Electrical motors can overheat, bind, fail, and possibly ignite surrounding materials. An accumulation of contaminants in the immediate area exacerbates the spread of fire in these instances.

c. Lightning Strikes.

Although very infrequent, there have been instances in which a lightning strike has initiated a fire. In these instances, faulty or contaminated insulation material contributed to the fire.

 d. Bleed Air Leaks.

Aircraft with systems that use air from the engine (bleed air) depends on a series of pneumatic lines to deliver the air supply. 

A failure of any of these supply lines, if left unchecked, can cause high temperatures in the surrounding area and damage to the aircraft’s equipment, wiring, and associated components. High-temperature bleed air leaks have caused in-flight fires and structural damage.

e. Faulty Circuit Protection.

A malfunctioning circuit breaker that does not open (trip) when it detects an abnormally high current draw may cause the affected unit or associated wiring to overheat and ignite.

f. Lithium-Ion Batteries.

Rechargeable lithium-ion batteries are capable of overheating, leading to a process called thermal runaway, which can cause the sudden release of the contents of the battery as a flaming jet, heavy smoke, unburned hydrocarbons, or in some cases the battery can explode or rocket. 

Once one cell in a battery pack goes into thermal runaway, it produces enough heat to cause adjacent cells to go into thermal runaway. The resulting fire can flare repeatedly as each cell ruptures and releases its contents.

(FAA AC No: 120-80A)


Crew Communication and Coordination

In the event of an in-flight fire, communication between the cabin crew and flight crew is essential. If a fire is discovered in the cabin, the cabin crew must inform the flight crew immediately. The firefighting effort requires coordination amongst the cabin crew.

The duties are divided into three main roles, the Firefighter, the Communicator, the Assistant Firefighter, all other cabin crewmembers play a supporting role.

A- The Firefighter

The first cabin crewmember that finds the fire will assume the role of the Firefighter.

The Firefighter:

     -  Alerts other cabin crewmembers

     -  Takes the nearest appropriate fire extinguisher

     -  Immediately locates the source of the fire

     -  Extinguishes the fire.

B- The Communicator

The second cabin crew member on the scene is in charge of communicating information about the fire. This cabin crew member, called the Communicator:

-   Informs the flight crew of the following:

                                 i.         Fire location

                                  ii.         Fire source

                                  iii.         Severity/density of fire and/or smoke (color of smoke/odor)

                                  iv.         Time the firefighting action started

                                  v.         Firefighting progress

                                  vi.         A number of fire extinguishers used.

-  Maintains the communication link between the cabin and the flight crew, via an interphone near the firefighting scene.

-  Provides the flight crew with an accurate description of the firefighting effort, and the situation in the cabin.

 

C. The Assistant Firefighter

The third cabin crew member on the scene assumes the Assistant Firefighter role. The Assistant Firefighter:

-  Provides additional firefighting equipment

-  Supports the firefighting effort

-  Removes flammable material from the area

-  Must be prepared to replace the Firefighter, and change roles with the Firefighter, if required.

Support Crew Members Other cabin crew members who are not directly involved in the firefighting effort are required to assist, such as:

-   Relocating passengers

-  Providing first-aid

-  Calming and reassuring passengers.

After any fire or smoke occurrence, one cabin crewmember should be responsible for monitoring the affected area for the remainder of the flight, and for regularly reporting to the Purser. Then the Purser will report to the flight crew.

(Airbus Flight Operations Briefing Notes)

 

 

Summary

An in-flight fire is probably the most serious in-flight emergency and must be brought under control as soon as possible. Considering the crucial role that time plays in this type of emergency, no time must be lost when attempting to extinguish the fire.


Maged Saeed AL-Hadabi

I’m Instructor / Maged Saeed Al-Hadabi. ​ Air Cargo / IATA Dangerous Goods Regulations / Safety Management System Senior Instructor, Auditor [ Yemen Airways] . Approved IATA DGR/ SMS Instructor by Yemen Civil Aviation Authority. We hope you find Aviation Professional website not only informative, but interesting and helpful as well. Leave your comment , thank you.

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