Photo: Air Force fire fighters in training, from Wikimedia Commons.

Eddie Sez:

After a few cabin fires in my Boeing 707 squadron we came up with this bit of wisdom: If you don't put a cabin fire out in eight minutes or less, you probably won't. If you are on fire and don't land the airplane in fifteen minutes or less, you probably won't. Now you will see that in just about so many words in AC 120-80 In-flight Fires, ¶8.A.

In the Gulfstream world, airplane cabin fires of all kinds have been consolidated into one checklist (G450 Quick Reference Handbook, page EC-8) but there are a few things you need to have memorized: G450 Abnormal Procedures / Cabin Fire.

It is helpful to have a basic understanding of what is needed for a fire to occur, what can cause an aircraft cabin fire, and what you have at your disposal to fight it. More about this: Technical / Fire.

More about aircraft fires:

Of course different aircraft manufacturers and operators may have their own specific procedures you need to follow and you must always temper these with some common sense. Should you always deploy the passenger oxygen masks? A reader bring ups a good point, see Letter to Eddie, below.

What follows are quotes from the references listed below, with my comments and techniques shown in blue.


A Brief History Lesson

[AC 120-80A, Appendix 3.]

Date Location Aircraft Type Time to Become Non-Survivable (Minutes) (see:)
07-26-1969 Biskra, Algeria Caravelle 26 Mishaps / Air Algerie 73
07-11-1973 B-707 Paris, France 7 Mishaps / Varig 820
11-03-1973 Boston, USA B-707 35 Mishaps / Pan Am 160
11-26-1979 Jeddah, Saudia Arabia B-707 17 Pakistan International Airlines 740
06-02-1983 Cincinnati, USA DC-9 19 Mishaps / Air Canada 797
11-28-1987 Mauritius, Indian Ocean B-747 19 Mishaps / SAA 295
09-02-1998 Nova Scotia, Canada MD-11 16 Mishaps / Swissair 111

"Fight the fire, land if you have to."

This philosophy was the rule of the skies until an Air Canada DC-9 changed the way we think about cabin fires forever. In 1983 the captain of Air Canada Flight 797 delayed the decision to land for six minutes while his crew fought a lavatory fire. They were airborne for nearly 20 minutes before he managed to get the aircraft on the ground. After the exits were opened the aircraft burst into flames, killing 23 passengers as the remaining 18 passengers and 5 crewmembers made it out.

"Point the airplane to a landable surface and fight the fire."

Fifteen years later, the crew of Swissair 111, en route from Boston to Geneva, detected what they thought was air conditioning smoke and elected almost immediately to return to Boston, less than four minutes after first detecting the odor. A minute later they opted for the closest airport, Halifax. In the next fifteen minutes, however, they declined direct routing to allow time to run checklists, prepare for the landing, and to allow for fuel dumping. After multiple aircraft systems began to fail the crew declared an emergency and requested an immediate landing. They impacted the water six minutes later, nearly 21 minutes after first detecting the odor, which turned out to be an electrical fire. All 243 on board perished.

The statistics are clear: If you don't put a cabin fire out in eight minutes or less, it will probably become uncontrollable. If you have an uncontrollable cabin fire and don't land in fifteen minutes or less, you may lose the airplane and all on board. Make no mistake about it: if you have a cabin fire you are in a battle against an enemy that has time on its side.

"Point the airplane to a landable surface, put the airplane on the ground as soon as possible and fight the fire if you can."

The key to surviving a cabin fire is speed: You should know how to fly your airplane's fastest possible approach and landing. Doing this requires practice and knowing exactly what to do without reference to checklists.


Subtle Causes on In-Flight Fires

[AC 120-80A, ¶8.]

  1. Wiring Failures. A majority of hidden in-flight fires are the result of electrical arcs along 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.

  2. 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.

  3. 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.

  4. Bleed Air Leaks. Aircraft with systems that use air from the engine (bleed air) depend 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.

  5. 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.

  6. 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.

Indications of Hidden Fires

[AC 120-80A, ¶9.]

  1. Abnormal Operation or Disassociated Component Failures. Failure or uncommanded operation of an aircraft component may indicate a developing fire. Electrical connections and the components themselves may have had damage from a fire in the area of the component or at any point along its power supply line. For this reason cabin crewmembers should report all failures of electrical items to the flightcrew in accordance with company policy.

  2. Circuit Breakers. Circuit breaker(s) tripping, especially multiple breakers such as entertainment systems or coffee makers may be an indication of damage occurring in a hidden area common to the affected components.

  3. Hot Spots. Hot spots on the floor, sidewall, ceiling, or other panels should be immediately investigated.

  4. Fumes. This may be one of your first indications of an impending fire. Never ignore a strange odor; you need to identify its source as soon as possible.

  5. Visual Sighting of Smoke. Smoke coming from vents or seams between interior panels, especially from the ceiling area, is a sure sign of a problem, and you should take immediate action to determine the source.

Priority One — Get the Airplane on the Ground (Speed is Life)

Figure: 15 minutes, from Eddie's notes.

If you can dedicate a crewmember or able bodied passenger to fight the fire, do so. (More about that below: Fight the Fire.) But the clock is ticking and if the fire fighting effort fails, another clock is ticking too. You want the airplane on the ground in fourteen minutes or less. Aviation history is against you if you take longer than that . . .

[AC 120-80A, ¶13.A.]

  • In-flight fires left unattended, particularly those that are not readily accessible, may lead to catastrophic failure and have resulted in the complete loss of airplanes. Fire tests conducted by various regulatory authorities have shown that fires allowed to spread into the aircraft's overhead area may become uncontrollable in as few as 8-10 minutes.

  • Studies have also shown that a flight crew may have as few as 15-20 minutes to get an aircraft on the ground if the crew allows a hidden fire to progress without any intervention. Appendix 3 [below] provides various illustrations of the time from the first indication to the crew of the presence of a hidden fire until it becomes catastrophically uncontrollable. These studies and other experience indicate that flight crewmembers should begin planning for an emergency landing as soon as possible after the first indication of fire. Delaying the aircraft's descent by only a couple of minutes might make the difference between a successful landing and evacuation and complete loss of an aircraft and its occupants.

Starve the Fire From the Cockpit

Typical corporate and airline aircraft interiors can make detecting the exact origin of a fire difficult. What you may think is air conditioning smoke may actually be an electrical fire. Smoke from behind an electrical panel door could be ventilation air from the engines. No matter the source, it may be prudent to have an immediate action plan on how to remove all possible threats while leaving the airplane still flyable and capable of shooting an instrument approach to a landing. Most aircraft manufacturers provide detailed checklists that are exhaustive in scope, but too time consuming to complete. Post accident simulator tests following the Swissair 111 crash revealed most crews required 20 to 30 minutes to complete the MD-11 Smoke/Fumes of Unknown Origin checklist. The fire became uncontrollable in half that time and the aircraft impacted the water 21 minutes after the fire was first detected.

If your smoke and fumes checklist, or checklists, can't be completed in just a few minutes, you should devise an immediate action plan in a flight simulator to remove as many likely suspects as possible, while still leaving the airplane capable of navigating to a runway and shooting an ILS approach.

Some aircraft, such as the Challenger 605, will automatically shed all non-essential electrical loads when the air driven generator is deployed. The crew can then focus on isolating bleed air systems.

Not all aircraft have easy, one-step solutions to combating a fire of unknown origin. But even very complicated procedures can be broken down into the required immediate actions. In a Gulfstream 450 or 550, for example, you can remove all electrical power from the airplane except the standby electrical system and still be able to communicate, navigate, and land. You can also remove half of the engine bleed air without fear of depressurization. An immediate action flow can be completed in 30 seconds:

  1. Don pilot oxygen masks.

  2. Deploy passenger oxygen masks.

  3. Turn off all cabin and auxiliary master switches.

  4. Open the fuel crossflow valve and ensure main boost pumps are on.

  5. Close the bleed air isolation valve and turn off the left engine bleed switch.

  6. Activate the standby electrical system.

  7. Isolate the main AC buses, and turn off both engine driven AC generators.

If the smoke continues you can open the left bleed switch and close the right bleed switch. Once the aircraft reaches a lower altitude, you can shut both bleed switches. This immediate action flow duplicates six pages of very well written checklist procedure into 30 seconds and gives you your best chance of starving a fire before it becomes uncontrollable.

While you are waiting for signs the fire is extinguished or will become uncontrollable, you must focus on getting the airplane on terra firma.

Getting the aircraft on the ground (on your own terms)

You need to think these things through and practice in a simulator, but remember your overriding concern is getting on the aircraft on the ground in fourteen minutes or sooner, even if you have to break something. With each simulator practice we get better at this, but there is room for improvement:


Priority Two — Fight the Fire (if you can)

On the Ground

Get away from the aircraft, do not delay to fight the fire.

In Flight

Figure: 8 minutes, from Eddie's notes.

[AC 120-80A, ¶13.A.]

  1. How critical are small in-flight fires? In-flight fires left unattended, particularly those that are not readily accessible, may lead to catastrophic failure and have resulted in the complete loss of airplanes. Fire tests conducted by various regulatory authorities have shown that fires allowed to spread into the aircraft's overhead area may become uncontrollable in as few as 8-10 minutes.

  2. As a crewmember, what should I do if I suspect a hidden fire? In accordance with company policies and procedures, coordinate with other crewmembers as applicable and take immediate and aggressive action to locate and extinguish the fire.

  3. Is it necessary that I locate the exact source of a fire before applying extinguishing agent? If possible, yes. For example, a fire located behind a panel or within a cupboard area in the lavatory probably would not be successfully extinguished by discharging a fire extinguisher into the lavatory without first opening the cupboard or gaining access to the area behind the panel where the fire is located. An additional example would be a fire in the overhead area above a ceiling. Depending on the volume of the overhead area, discharging a fire extinguisher randomly without attacking the base of the flames or smoldering material probably would have no effect on the fire. It is unlikely that a fire in this area would be extinguished unless extinguishing agents were applied directly to the base or source of the fire.

  4. Should I consider cutting or punching a hole in an aircraft cabin wall, ceiling, or floor panel in order to gain access to a fire? If this is the only way to gain access to the fire, yes. In this situation, the risk of damaging equipment behind the paneling and the possibility of creating a bigger problem must be weighed against the catastrophic potential of in-flight fires left unattended.

  5. What resources can I use to access hidden fires? You should consider all available resources to access a hidden fire. Items found in carry-on baggage might be useful non- traditional resources, such as a shoehorn, knitting or crocheting needles, walking canes, and fairly rigid items that could pry apart paneling.

  6. What is the best way to locate hot spots on a door or interior panel before attempting to open or remove it? While there is no single best method, we suggest using the back of your hand instead of your fingers or palm. The skin on the back of your hand is more sensitive to temperature variations than your palm or fingertips. Using the back of your hand allows you to be more aware of temperature fluctuations as you run your hand along a panel making it easier to locate hot spots on the panel. Also, using the back of the hand protects your palm and fingers from being immobilized in case the object is so hot that it could burn your hand. For example, if you were to grasp a hot door handle (e.g., lavatory door) using the palm of your hand, there is the possibility of burning your hand. A burned hand would make your fire fighting activities more difficult and could cause a delay in extinguishing the fire and conducting an evacuation of passengers.

  7. As a crewmember, if I suspect a fire in a lavatory, what action should I take?
    1. If you suspect a fire in a lavatory you should immediately notify another crewmember, get the closest fire extinguisher and check the door for heat.

    2. Cautiously and slowly open the lavatory door. Try to locate the source of the fire and discharge the fire extinguisher at the base of the fire. If you cannot clearly identify the source of the fire aggressively attempt to locate the cause of the smoke and extinguish the fire. If the base of the flames or the source of the fire cannot be readily identified, do not discharge the agent with the intent of suffocating the smoke. This is not an effective way to fight a fire and would only waste valuable extinguishing agent when the source or base of the fire is not accessible. Remember, it is critically important that you protect yourself from the effects of smoke and fumes while attempting to fight a fire. Do not enter an enclosed area or begin to battle a fire that is generating heavy smoke without first donning your protective breathing equipment (PBE). A small fire can quickly grow to be large and uncontrollable. Time is critical when combating an in-flight fire and every available resource must be used to locate and extinguish it. Research has shown that a fire left uncontained can destroy an aircraft in as few as 20 minutes and a smoke filled cabin can be completely consumed by fire in as few as 6 to 10 minutes.

[AC 120-80A, ¶14.]

[AC 120-80A, ¶15.]


More Techniques

Using a Halon Fire Extinguisher

Using a Water Fire Extinguisher

Always maintain in an upright position.

Galley Fire

Baggage Compartment Fire

Passenger Personal Electronics


Letter to Eddie about Cabin Fires

Hello,
Always enjoy perusing your website with all the references & etc.
Specifically, looking at "Cabin Fire" or "Smoke" - absolutely spot on and consistent with all operations. Just wondering about deploying passengers O2 masks - in B767 operations it isn't recommended or mentioned in the checklist. The oxygen released could exacerbate the problem (especially if the source of smoke or fire is unidentifiable). I suppose in a corporate jet the volume of oxygen would be much smaller and some pretty "well heeled" passengers would want their fair share of O2!
Anyway, just another view point from another angle - once again thanks for the obvious effort put in your website.
Keeping the blue side up,
M

Figure: Passenger oxygen mask pin, from Eddie's aircraft.

M,
Thank you for your kind words. You are quite right about a possible danger from the use of passenger oxygen and I get some email on that topic. As with many things in aviation, the answer isn't clear cut and really depends on the airplane.
The passenger oxygen masks on the Gulfstreams that I fly are identical to what are found on most airline type aircraft. The oxygen lines are pressurized to drop the masks but oxygen does not flow into the masks until a pin, usually connected to the mask via a line of string, is pulled. At that point what little oxygen that is provided should be inhaled, the extra put into the bag attached to the mask. That being said, the danger is real.
My advice in our operations is to follow the aircraft manufacturer's procedures unless you have a good reason to deviate. Gulfstream says we should deploy the masks. I think I would be inclined to do so unless we had visible flames in the cabin.
Thanks again!
Eddie


Book Notes

Portions of this page can be found in the book Flight Lessons 2: Advanced Flight, Chapter 4.


References

Advisory Circular 120-80A, In-flight Fires, 12/22/14, U.S. Department of Transportation

Gulfstream G450 Quick Reference Handbook, GAC-AC-G450-OPS-0003, Revision 34, 18 April 2013

National Fire Protection Association

Wikimedia Commons, Public Domain Artwork