In-Flight Firefighting Guidance Needs Improvement, Experts Declare

A new advisory circular (AC) on in-flight fires calls for "immediate and aggressive" action on the part of crewmembers, but it falls short in laying out what those actions should be, according to two experienced airline captains who are recognized authorities on in-flight fire.

Indeed, the AC provides an example of an expedient means of fighting fires while airborne that may well reveal the inadequate state of preparedness for fighting a fire in flight. The AC suggests that a soda can from the galley can be shaken, and the pop-top tab pulled, allowing a cabin attendant to spray the contents onto a fire. However, it is not until elsewhere in the text that the AC cautions against using soda pop on an electrical fire (sugar facilitates the conduction of electricity).

The AC is an outgrowth of various National Transportation Safety Board (NTSB) investigations into in-flight fire events and the Transportation Safety Board (TSB) of Canada's investigation into the Swissair Flight 111 disaster. The NTSB issued a recommendation Jan. 4, 2002, some 39 months after the Swissair crash, calling on the Federal Aviation Administration (FAA) to issue an advisory circular (AC) stressing to aircrews facing in-flight fire the need to take "immediate and aggressive action" to locate and extinguish the fire (see ASW, March 8). Another two years passed before the AC was published. The AC appears intent on honoring the NTSB's intent. The words "immediate and aggressive action" are used no less than eight times in the 15-page AC.

Of interest, while the AC is in major respects an outgrowth of the Swissair crash, it does not mention this case as one of the pre-eminent examples of how quickly undetected fire in a closed but ventilated space containing flammable material can turn into a raging inferno.

While an engine fire checklist represents a straightforward drill, investigating and attending an electrical fire of unknown origin has many other facets, but the AC addresses none of these issues:

The need for the pilots to remain seated and fly the jet (yet be kept fully informed).
The spread of the fire once it gets a life of its own and the associated countdown time to loss of control.
The electrical consequences and the question of whether or not to quickly reduce to a minimal electrical power configuration. The issue is as fundamental as turning off a gas stove in a domestic kitchen fire.
Can the fire be fought? Or is it a ValuJet Flight 592 situation of burnthrough from another inaccessible compartment?
The consequences of switching air conditioning pack status and changing the ventilation patterns (venting the smoke, or closing the outflow valve, for instance). Recall that turning off the cabin bus, and hence cutting power to the recirculation fans in the attic space above the cabin had, lethal consequences for Swissair Flight 111. The fire drawn aft then reversed course and worked its way forward to the cockpit.
The aircraft configuration for approach and landing. How disabled is the aircraft?
Passenger anxiety or panic levels in the presence of unbreathable toxic air and/or the actual appearance of fire and smoke. Things could suddenly worsen in the cabin by opening smoke vents and cockpit sliding windows, or by switching air conditioning packs back on in an attempt to freshen cabin air.
In the case of a suspected electrical fire, the AC does not emphasize the need to depower the airplane to all but basic flight-essential systems - as suggested by former test pilot John Farley (see ASW, March 22). Nor does it emphasize the need for integrated crew firefighting training in realistic scenarios. Finally, the AC does not address the new security reality - that cockpit doors are locked in flight. Thus, if the cabin-cockpit interphone system is knocked out, flight attendants cannot open the cockpit door to report a fire situation to the pilots. It should be noted that the electronic locks on cockpit doors might also be frozen should electrical power be lost, as is often the case in electrical fires.

"This AC represents a start, but it falls short of the kind of detailed, consistent guidance and 'best practices' that the industry needs," said Capt. Ken Adams. "A second edition of this AC can vastly improve upon its shortcomings."

In its present form, Adams likened the quality of the AC to the pink slip given by an FAA examiner to a pilot who fails a check flight. "The pink slip basically takes away your license until a successful recheck," Adams explained. Similarly, he believes a rewrite of the AC is in order.

Adams participated in the Swissair Flight 111 investigation as the lead investigator for the International Federation of Air Line Pilots Associations (IFALPA). As such, he is intimately acquainted with the in-flight firefighting deficiencies revealed during the course of the Flight 111 inquiry. In 1999, he presented a comprehensive approach to cockpit and cabin fire safety (see ASW, Nov. 1, 1999).

In concert with Capt. Peter Budd, former vice chairman of the IFALPA accident analysis committee, the two captains believe the new AC glosses over key issues.

Typically, problems develop rapidly and unexpected system failures may occur unrelated to fire. Cockpit warnings may not necessarily signify the failures they were intended to, hence the term "brown herring." This expression is a variation of red herring, an expression used to describe a misleading or irrelevant distraction. The phrase "brown herring" comes from classic military parlance, as in, "Captain, we have a dark brown smell down the back."

Automation may exacerbate the danger. Electrical failure and fire burning through inter-related systems and interdependent components may take the challenge of operating the systems into a Twilight Zone lying lethally beyond the pilot's perplexed musing, "What's it doing now?" The term "electronic system nightmare" is featured in one of the pertinent examples of in-flight fire.

Maintaining flight control to "land ASAP" may be simpler said than done. Any in-flight fire that is allowed to develop - through a combination of excessive trouble shooting and not powering down all nonessential electricals - is already out of control. At this unfortunate point, the real task becomes trying to establish when loss of flight control might occur, and to act accordingly (e.g., accelerate descent, declare Mayday, etc.). As a general rule of thumb, loss of control may be imminent when any two of five suggested factors becomes applicable. Indeed, the AC could employ these factors to more strongly make its points to aircrews that they must not tarry - cut power to non-essential electrical systems and begin descent before the point of zero return. >> Adams, e-mail kmuleadams@bellsouth.net<<

The Point of Zero Return
When any two of the following factors is operative, the situation has escalated to a non-survivable proposition:

Unexpected systems failures and circuit breaker trips are happening so frequently that it is virtually impossible to cope logically with the changing considerations (i.e., the event is outrunning the brain's ability to cope).
When things are happening so fast that the plan also must change frequently (e.g., from "Should we dump fuel?" to "No time for dumping; must get this airplane down now").
When answers from the cabin staff are not forthcoming and smoke, visibility and passengers' breathing are starting to become paramount concerns. Pilots become aware that the cabin staff is using portable breathing equipment and hand-held fire extinguishers.
When failures are uncharacteristic of the warnings (e.g., stick shaker actuated by a static port heater fire burning through a static line). The AC places this activity at the top of its indications of hidden fire: "Abnormal operation or disassociated component failures ... may indicate a developing fire."
When the existing divert plan/distance-to-run is suddenly looking non-viable due to an accelerating deterioration of the situation.
Pertinent Examples of 'Brown Herrings'
Or, how rapidly problems can develop and how unexpected and varied system failures can occur, often involving warnings and alerts not necessarily signifying system failures for which they were intended:

March 5, 2004: A B717 operated by AirTran Airways [AAI] reported smoke in the passenger cabin during takeoff climb from Atlanta. At approximately 200 feet the number 6 display unit on the captain's instrument panel went blank and the engine alert display (EAD) left generator off alert displayed. The airplane had a complete electrical power failure and communications with the Atlanta Tower was lost. Emergency electrical power was restored. The flight attendants then advised the captain that there was smoke in the aft part of the cabin. The captain and first officer smelled an electrical fire. The captain returned to the airport and made an emergency landing. The bus-tie had failed to assure continuity of electrical power. Source: NTSB

March 26, 2003: A B717 operated by AirTran Airways. As the airplane neared the final approach fix [for landing in New York City] the master caution light illuminated; the left generator had failed. The display units (DUs), including the standby instrumentation, went dark. After loss of DUs, pilots noticed a burning smell in the cockpit. Emergency declared. First officer reported that the DUs continued to flash in a random order. Upon landing gear extension, a message of unsafe landing gear commenced, and continued until after landing.

The flight attendants noted that on approach, the cabin lights extinguished, and the emergency light illuminated. After a short period of time, the emergency light extinguished. The lead flight attendant noted that when she punched the buttons for the public address system, the buttons did not illuminate on the handset used for making announcements and for communicating with the cockpit.

After landing, examination of the airplane revealed that the left side power conversion distribution unit (PCDU), located in the forward electronics bay, exhibited evidence of sooting and had a burned odor. Source: NTSB

From a 1991 incident report: After an emergency landing and as the aircraft passed a taxiway turnoff, the tower advised that they saw fire on the left side of the aircraft. This was the first time the crewmembers were aware of any fire. This incident is an example of an electronic system "nightmare." The crew had to sort out 42 EICAS [engine indication and crew alerting system] messages, 12 caution/warning indications, repeated stick shaker activation and abnormal speed reference information on the primary flight display. Many of these indications were conflicting, leading the crew to suspect number one engine problems when that engine was actually functioning normally. There was no indication of fire presented to the crew although a fire actually existed. Source: Billings. C. E., (1996) Human-Centered Aviation Automation: Principles and Guidelines, National Aeronautics and Space Administration, Technical Memorandum 110381

And a supersonic 'brown herring'

On Oct. 4, 2003, a British Airways Concorde on initial climb after departure from Heathrow, a No. 1 air group 'AIR & SMOKE' amber caution illuminated on the main warning system. A slight smell was discernible by the flight crew and some smoke was visible on the flight deck. Both the smoke and the smell cleared rapidly. The warning caption immediately reappeared, however ... No smell or smoke accompanied the second warning. Some 30 minutes later, a No. 2 Air Group 'AIR & SMOKE' amber warning caption illuminated, but on this occasion there was no smell or visible smoke. The No. 2 Air Group was shut down and the aircraft continued to its planned destination without further incident. In light of the fact that Concorde has since been withdrawn from service, no further investigation was considered necessary. Source: UK Air Accidents Investigation Branch, Bulletin No. 4/2004
Analysis of AC 120-80, In-Flight Fires
Paragraph in the AC Comments of Captains Adams and Budd
1.c. Approved manufacturer's procedures and company procedures take precedence over the information presented n this AC. The importance of crewmembers taking immediate and aggressive action to locate the source, gain access, and effectively apply extinguishing agent to hidden fires cannot be overstressed. Begs the question of a firefighting philosophy - the integrated, strategic approach called for by the Transportation Safety Board (TSB) of Canada (see ASW, March 8 and Dec. 11, 2000) Without a defined philosophical approach to fighting in-flight fires, the procedures developed by the manufacturer or operator inherently will be inadequate (see ASW, March 15). Checklist design, font size, location of the checklist so it can be found under restricted visibility conditions, are just a few of the specific things that boil out of a well-defined philosophy.
2.c. Circuit Breaker. CBs are designed to open an electrical circuit automatically at a predetermined overload or current. This working definition does not mention "arcing faults" that generally do not trip CBs. Crews need to be made aware of this. The crew could have a high energy arc which could ignite insulation and not have any indication that an electrical circuit is the source of the fire.
3.a. Wiring failures. A majority of hidden in-flight fires are the result of electrical arcs along wire bundles igniting other surrounding materials, as contamination from spillage, accumulated dirt/dust on these surfaces can promote flame spread (uncontaminated insulation materials are generally very fire resistant). The re-setting of a tripped circuit breaker can overheat wiring, ultimately leading to failure and arcing, causing the same chain of events. Insulation materials are not generally fire resistant. Wire bundles and wire insulation can burn readily. Metalized Mylar thermal acoustic insulation blankets and several other types installed in aircraft are known to be flammable. The AC does not mention swarf along with dirt and dust. Swarf, the metal shavings and detritus from drilling, can sprinkle onto a wire bundle. The sharp metal bits wedged in the wiring can greatly accelerate wear of insulation, creating the potential for arcing.
4.c. Hot Spots. Hot spots on the floor, sidewall, ceiling or other panels should be immediately investigated. The intention is excellent. However, the actions in order of priority need to be (1) self-preservation, by donning protective gear such as smoke masks and goggles, (2), ensure that all crewmembers are informed, and (3) investigate for the source. What is the most appropriate method to investigate? Airlines have varying levels of expertise to determine the location of a hidden fire. A common level of risk management is needed.
4.d. Odor. This may be one of the first indications of an impending fire. Pilots should never ignore a strange odor; they need to identify its source as soon as possible. The nose is perhaps our most reliable sensory organ for early fire detection, but don't tarry. Taken literally this guidance could result in the crewmember being overcome by toxic gasses while determining the source. Self-preservation is the first priority.
4.e. Smoke. Smoke coming from vents or seams between interior panels is a sure sign of a problem. If the flightcrew can see smoke, they are probably halfway toward solving the problem.
5.a. Resources available for fighting in-flight fire. The answer depends on the aircraft's specific cabin configuration, which may vary within types. Therefore, crewmembers should include this subject in crew briefings as suggested in AC 120-48, "Communication and Coordination Between Flight Crewmembers and Flight Attendants." The guidance leaves it up to individual crews to determine the resources available on their aircraft. As for briefings, the AC has not been updated since 1988. There are no specific references to a "Fire Fighting Team" and how communications between cabin and cockpit crewmembers are to be maintained. Instances occur daily where the cockpit crew arrives with the aircraft fully loaded with flight attendants and gate agents ready for immediate pushback. The only time for a team briefing may be before the first flight of the day, yet the FAA does not specify minimum briefing times.
5.c. Crewmembers should consider using deadheading crewmembers and able-bodied passengers (ABP) as additional resources when combating a fire. The need to utilize these people indicates that the current crew complement is inadequate for the safety role designated by the FARs [Federal Aviation Regulations]. Train as you do; do as you train. Will an ABP be asked to descend into the electronics and equipment (E&E) bay to locate and fight a fire? Successful prosecution always will prove to depend less critically on the number of personnel involved in attending the fire and more on their knowledge, teamwork and assertiveness - which gets back to training.
6.b. The initial focus should be on extinguishing the fire and then following up with the appropriate class of fire extinguisher (See Appendix 4, extract below). App. 4, Para. D, Helpful hints (subpara. 3): Care must be taken not to direct the initial discharge at close range (less than 5-8 feet) because the high velocity stream may cause splashing and/or scattering of the burning material. Appendix 4 notes that Halon requires a 5-8 foot fighting zone. No cockpit provides such an area. How is Halon to be used in this environment? Is Halon the correct type of extinguisher for the cockpit? How is Halon or another extinguishing agent inserted behind panels? The FAA should set the requirement that only fire extinguishers capable of fighting Class A, B and C fires should be certified for use on commercial aircraft, with exceptions for Class D fires on aircraft that might have to deal with this type of conflagration1. Effort needs to be made to identify a single agent to meet all in-flight needs2.
6.d. Fire extinguishers equipped with flexible discharge hoses and nozzles are better suited to handle fires that may require discharging the agent in an upward direction or in any other situation requiring flexibility. The installation and use of extinguishers with flexible hoses is highly desirable for these reasons. This being the case, the FAA needs to: Identify suitable units. Mandate the use of such units. Mandate the training of crews to use the units in aircraft locations where they are likely to be needed. Ban the installation of fixed nozzle type units where their use is likely to be ineffective due to the likely location of in-flight fires. Such locations include cockpits with overhead panels and cabins with overhead bins or lockers that are above the horizon height of the 90th percentile of persons fighting the fire. To say that flexible hoses are "highly desirable" is a form of fence- sitting, as the benefits are identified but there is no guarantee that the flying public will receive the benefits.
8.c. Locate the exact source of a fire before applying extinguishing agent. In an aircraft as big as, say, the coming A380, it will be virtually impossible to locate the source before the fire has a chance to expand. As one example of what can be done on any aircraft, detectors could be located evenly spaced and close to electrical wires, cables, and bundles throughout the aircraft. The detectors would give flightcrews a much-improved capability to locate and eliminate the source of electrical smoke/fire.
8.d. Cutting or punching a hole in an aircraft cabin wall, ceiling, or floor panel in order to gain access to a fire. The AC as stated would cause the crew to doubt whether they should cut or punch through panels. Training in an aircraft to identify "low threat" areas where sidewalls and other panels could be breached should be required. For those places where punching a hole would NOT be appropriate, such panels could be identified and constructed so as to be easily removed without the use of "special tools" or the ice tongs mentioned as an expedient means in the AC.
9.a. Delaying descent by only a couple of minutes may make the difference between a successful landing and evacuation and complete loss of the aircraft. The manufacturer's FAA-approved fire/smoke checklist for the B737-800 does not mention "plan to land at nearest suitable airport" until the last step. Not all airlines call for powering down the electrical system. Some airlines call for opening the cockpit windows for smoke evacuation. No common philosophical approach to fighting fire/smoke has been stated or required by the FAA. Providing AC guidance on what constitutes best practice might be more appropriate.
9.b. Flight crewmembers must don smoke goggles and oxygen masks at the first indication of smoke or fumes. Smoke goggles have proven to be ineffective. It is time for the FAA to require "full face smoke/oxygen masks" on commercial aircraft. They have been in use on military aircraft for decades.
9.c. If the original source of the fire cannot be determined, exercise caution when attempting to eliminate smoke and fumes from the aircraft. Your best defense as a flightcrew member is to have a good understanding of your aircraft's ventilation and/or pressurization systems and the location of major components within the fuselage. This scenario is a Pandora's Box for the crew. If they can't locate the fire, are they expected to fly in a cockpit full of smoke in which their ability to see the instruments is inhibited? Conversely, if the smoke and fumes are confined to the cabin, how are passengers to breathe if the smoke and fumes are not removed? Yet it is at this very point where a fire could flash over, filling the cabin with flames (when opening the vent introduces the backdraft).
10. If flight attendants are onboard, what can they do? The following team example assumes a crew of five with three flight attendants and two pilots. The crew member who finds the fire is usually the person who is the firefighter. A second crewmember may serve as communicator, relaying information to the flight deck. Another crewmember can assist by: Obtaining additional firefighting supplies. Relocating passengers. Distributing towels for passengers' use to cover their noses to filter out smoke. The example uses three flight attendants, which under FAA regulations means a maximum of 150 passengers. Distributing 150 towels is going to take one person 7.5 minutes, assuming the individual takes only three seconds with each passenger. A time and motion study of the tasks proposed does not appear to have been done.
10.c. Recommended procedures. Donning PBE (personal breathing equipment) is the second to the last action on an eight-item list. It should be the first, per our three-item order of priorities above.
12. Recommended training. Programs should stress the importance of crewmembers taking immediate and aggressive action when confronted with in- flight fires. This content needs expanding and the paragraph retitled "Required Training." It is recognized that an AC is advisory - up to a point. The FARs need to be changed to require more stringent training.
14. Related advisory circulars. AC 20-42C, Hand Fire Extinguishers for Use in Aircraft AC 25-9A, Smoke Detection, Penetration and Evacuation Tests and Related Flight Manual Emergency Procedures AC 25-16, Electrical Fault and Fire Prevention and Protection AC 120-48, Communication and Coordination Between Flight Crewmembers and Flight Attendants. The listed ACs have not been updated in some time and may not reflect current "best practices" in the industry: AC 20-42C: March 7, 1984 AC 25-91: Jan. 6, 1994 AC 25-16: April 5, 1991 AC 120-48: July 13, 1988 Average age of these ACs: 14 years.
Appendix 1. Contains synopses of four in-flight fires investigated by the NTSB: June 2, 1983, Fire on an Air Canada DC-9 and its emergency landing at Covington, Ky. Sept. 17, 1999, Delta Air Lines DC-9 fire, and its emergency landing coincidentally at Covington, Ky. Aug. 8, 2000, AirTran DC-9 fire and emergency landing at Greensboro, N.C. Nov. 29, 2000, American Airlines DC-9 struck by lighting and resulting fire on climb out of Washington, D.C.'s National Airport. The limited listing of four NTSB investigations ignore many others, including the TSB investigation of the Swissair Flight 111 disaster, and other states' investigative data and their recommendations, such as the UK's Air Accidents Investigation Branch (AAIB) and its concerns about fighting fires in inaccessible spaces. As a result of these omissions, an opportunity may have been lost to present valuable insights on such topics as: Checklist design and font size. Checklist philosophy. Fire training limited to external fires in metal pans in the U.S., while the Europeans are using cabin fire trainers.
Notes: 1 Classes of fire: A, ordinary combustible materials such as wood, paper, rubber, plastics, etc.; B, flammable liquids, oils, greases, tars, oil base paints and lacquers; C, energized electrical equipment fires; D, fires involving combustible metals such as magnesium titanium, etc., requiring dry powder extinguishing agents. 2 Appropriate extinguishing agents by fire type: Water: Class A Halogenated hydrocarbons (Halon): Class A, B, or C Dry powder: Class D
Sources: FAA, NTSB, Captains Adams and Budd

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