Fire on board

Fire is one of the most hazardous situation as it spreads so quickly, as according to statistics affected aircraft has only 17 minutes to initiate emergency descent, perform emergency landing and evacuate the passengers. Otherwise without aggressive intervention by the flight crew the aircraft will burn to ashes.

Cause

Fire may be caused by a number of reasons:

• technical problems ( electrical system malfunction, electrical short circuit, engine failure which was due to ingestion of debris or bird strike, ignition of dangerous easy-flammable goods during transportation )

• outside factor ( lightning strike, hail, severe turbulence, bird strike )

• human factor :

√ Passengers’ error. Most carriers prohibit smoking in the aircraft. This, coupled with the use of fire resistant materials, has reduced the likelihood of fire caused by a cigarette. Nevertheless, despite it minority of passengers continue to smoke in the lavatories. Thus not extinguished cigarette can pose risk to the safety. Explosion of bomb by terrorists can obviously lead to fire.

√ Cabin crew error. Airlines comment that most in-flight and ground fire/smoke events relate to the galley and involve some kind of electrical equipment. Oven fires may occur because of items(which are not heat resistant) being placed inside the oven by FAs (e.g. oven being used as storage place for folders or checklists, or to dry shoes) or because of overheating, or electrical overload/short circuit. In addition to ovens, there is a lot of equipment in the galley wrong usage of which can cause a fire (e.g. coffee or water heaters on without any water in).

√ Airport security officers’ error. Overhead compartment fire is often caused by passengers’ hand luggage which was not thoroughly checked (e.g. nail polish remover, medicinal or toilet articles, safety matches, and other prohibited items).

√ Flight crew / loaders error. Loosely packed dangerous goods ( which are not thoroughly controlled by pilots) by loaders can ignite due to friction.

The International Civil Aviation Organization defines Dangerous goods as “ articles or substances which are capable of posing risk to health, safety, property and the environment.”

Dangerous goods fall into 9 classes:

Class 1: Explosives – Explosive substances, explosive articles, and pyrotechnic devices, for example, ammunition, and fireworks.

Class 2: Gases

Class 3: Flammable liquids – Examples are petrol, alcohol, and perfume.

Class 4: Flammable solids – Examples are matches, flammable metal powder

Class 5: Oxidizing Agents and Organic peroxides

These substances are sensitive to impact or friction, or may create a dangerous reaction when in contact with other substances. They may be explosive and burn rapidly. Some examples are fertilizers and chemicals.

Class 6: Toxic (poisonous) and infectious substances

Those substances that are liable to cause death or injury if swallowed, inhaled or absorbed through the skin. Examples are pesticides and poisons, mercury.

Class 7: Radioactive materials

Class 8 Corrosives .

Class 9 Miscellaneous - Hazardous substances such as dry ice and magnets.

Dangerous goods fall into three types:

1. Goods that are acceptable on passenger and cargo aircraft

2. Goods that are acceptable on cargo aircraft only

3. Goods that are prohibited for air transportation

Goods which are strictly prohibited for transportation in the cabin are

• Explosives - fireworks, flares, toy gun caps

• Compressed gases - filled or partly filled aqualung cylinders

• Flammable liquids and solids - lighter fuel, non-safety matches, paints

• Oxidizers - some bleaching powders

• Poisons

• Irritating materials - Tear gas devices

• Infectious substances - live virus materials

• Radioactive materials - medical or research samples which contain radioactive

sources

• Corrosives - acids, etc.

• Magnetized materials - instruments containing magnets.

Consequences

Fire on board can result in

• High stress level in the cockpit

• Engine failure

• Pressurization problems

• Shortest high speed vector to land

• Poor R/T (oxygen mask) or loss of R/T

• Passenger evacuation

• RWY blocked

Types of fire

Engine fire.

Engine fire is normally detected and contained satisfactory by the aircraft fire detection and suppression systems. But there are such situations when fire can not be determined by onboard systems and it can spread to the wing and the fuselage .Even when engine fire was eliminated the crew need to land the aircraft as soon as possible so that the fire will not break out again.

Cabin fire.

Cabin fire can be easily detected and put out by usage of fire extinguishes. It is also advisable to perform landing as soon as possible in order to investigate the problem.

Hidden fire.

Hidden fire can be detected by onboard systems or by passengers noticing smoke or fume. It is very hazardous as smoke can fill up the cabin and can reduce visibility and lead to suffocation and choking.

Effects

t the first indication, or suspicion, of smoke and fumes, or fire within the aircraft the flight crew will don smoke goggles and oxygen masks. The wearing of oxygen masks may make the voice messages more difficult to understand.

Secondly, the crew will attempt to find the source of the smoke or fire and eliminate it. Different emergency equipment may be used, such as smoke detectors, fire extinguishes, fire gloves, fire goggles, hoods, crash axe, emergency chutes for evacuation.

• Smoke detectors. Optical Smoke Detectors are installed in aircraft toilets and usually in cargo compartments as well. They are usually only activated by a significant reduction in visibility due to thick smoke from, say, a waste bin fire. Cigarette Smoke will not usually activate them.

• Portable fire extinguishers. Portable extinguishers are to be found in the cockpit and in the cabin. They are designed to fight small fires and thus their capacity is limited.

• Fire/crash axe. Fire axes are provided to obtain emergency access to areas and parts of the airplane which are not easily accessible (e.g. behind sidewall, electrical or ceiling panels).

• Fire protection gloves. These gloves are kept in the flight deck and/or in the cabin to protect the user against heat/fire. They can also be used to handle hot or sharp objects.

• Smoke hoods. It is a smoke protective device which incorporates a small oxygen generator, which provides the wearer with Oxygen for a limited amount of time, typically 15-20 minutes.

• Smoke goggles. Smoke goggles may be found in the flight deck for use with smoke hoods. Some aircraft are equipped with oxygen masks with integral smoke goggles.

• Fire Blankets. Some operators have fire proof blankets onboard which can be used to suffocate a fire by cutting off the supply of oxygen.

When crew members manage to extinguish fire, the captain will evaluate the situation and make up his mind about the further actions. But in the majority of cases he’ll give preference to land as soon as possible for further investigation if any systems were affected by fire.

If fire is uncontrollable and pilots will

- put on oxygen masks if there is smoke or fire in the cockpit

- initiate emergency descent without any delay (otherwise it will take an aircraft a few minutes to burst into flames and burn fully)

- set squawk 7700

- declare Mayday

- proceed to nearest suitable airport and request priority for landing or

- try to find appropriate place for landing ahead of them( off-field landing or ditching)

- request fire brigade, ambulance, search and rescue team

- upon landing start immediate evacuation of passengers (After disembarkation for safety reasons they have to be removed on 100meters distance from crippled aircraft.)