Fatal fire hazards find hiding places inside planes


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Posted 6/7/2004 11:49 PM

Fatal fire hazards find hiding places inside planes

Every second brought Delta Air Lines Flight 2030 closer to disaster.

First came the odor, like burning matches. Then an acrid haze settled into the cabin. Flight attendants raced to find the smoke's source until a man in row 11 complained that the floor felt hot. Flames glowed through an air vent beneath his seat. (Related graphic: Anatomy of disaster)

But the captain and chief flight attendant didn't try to put out the fire. Quite the opposite they ordered the crew not to use the plane's fire extinguishers. "Absolutely do not spray the extinguisher," the lead attendant said, according to an investigator's report of the incident on Sept. 17, 1999.

Luckily for the 118 people aboard, flight attendant Denene Green didn't wait for permission. The flight landed safely after

 Green, who hadn't heard the order, sprayed an extinguisher and put out the fire. Investigative records show the crew's lapse occurred because of apparent miscommunication and failure to follow airline guidelines.

The confusion and lack of effective training about how to deal with fires shocked federal accident investigators, who say in interviews and public records that fires remain a serious threat to passenger aircraft.

In a recent formal recommendation, the National Transportation Safety Board concluded that "training programs still do not adequately prepare crewmembers to fight the type of hidden in-flight fires likely to occur on airplanes."

NTSB officials say that the Delta flight had similarities to Swissair Flight 111, one of the worst air disasters involving fire. The MD-11 jet crashed off Nova Scotia in 1998 after a blaze began above the ceiling. All 229 people on board were killed.

Yet nearly six years after the Swissair disaster, several proposed safety improvements to prevent such accidents have not been required by law. U.S. and Canadian accident investigators are calling for improved airline training, the removal of flammable material and rules to require smoke detectors and automatic extinguishers throughout planes.

Aviation regulators such as the Federal Aviation Administration have mandated many improvements in recent decades to protect flights from fires, and other actions are on the way. But regulators, airlines and aircraft manufacturers say that some of the proposals by safety advocates are impractical or could even make flights riskier, not safer. They say fatal fires already are extremely rare.

Accident investigators acknowledge that few planes have crashed because of fires only three fatal accidents in the USA since 1980. But the number of unpublicized incidents such as the Delta flight and the defenselessness of crewmembers against a raging fire have convinced them that the risks are real.

In investigative records, they cite these other cases:

Three flight attendants and an off-duty pilot sitting in first class failed to use extinguishers on an Aug. 8, 2000, AirTran Airways flight as heavy smoke spewed from an electrical panel. The pilots told investigators that they barely got the DC-9 back to the airport in Greensboro, N.C., because thick smoke in the cockpit made it difficult to see instruments.

One flight attendant later told investigators that she thought about using an extinguisher but didn't know where to aim it. The off-duty pilot said he feared that the chemical used in the device Halon, a powerful extinguishing agent that can be toxic in high concentrations would "take away more oxygen" from the cabin air.

A fire broke out in the "attic" above the cabin ceiling of an American Airlines flight on Nov. 29, 2000, after the MD-80 jet was struck by lightning. A flight attendant tried to shoot Halon at the ceiling panel, but it had no effect. A passenger cut through a ceiling panel with a pocketknife so the attendant could shoot Halon directly at the fire and put it out.

That solution would no longer be available: Passengers have not been able to carry knives since terrorists used them in the Sept. 11 hijackings.

"We've had many more ... that were close to being fatal," says Merritt Birky, a retired accident investigator with the NTSB who specialized in fires. "In some cases it was sheer luck that they weren't."

Some improvements made

The aviation industry has taken numerous steps in recent decades to reduce the risks from fires.

Seats and other materials inside cabins are more fire-resistant. Regulators ordered that airlines remove the type of insulation material that burned in Swissair Flight 111's attic, known as metallized Mylar, from more than 700 jets. The same material caught fire on Delta Flight 2030. And tougher flame-resistance standards for insulation installed in newly built planes go into effect in 2005.

After a fire in a cargo hold caused a ValuJet DC-9 to crash in the Florida Everglades on May 19, 1996, the government required airlines to install automatic extinguishers in below-deck cargo compartments.

Dozens of steps have been taken to make wiring, the source of most serious fires, less likely to spark. In January, the FAA issued guidance to airlines calling for upgraded firefighting training.

But investigators in the USA and Canada say more needs to be done.

In the months after the Swissair jet hit the water off Nova Scotia, Canadian officials issued numerous safety recommendations. But, just as in the U.S. system, the Canadian Transportation Safety Board has no power to order changes. Some of the recommendations have never been mandated by Canadian regulators or other aviation agencies around the world.

"The board has yet to see significant industry-wide improvements in certain important areas," the Canadian Transportation Safety Board wrote last year in its final report on the Swissair crash.

For example, the Canadian board says that the vast majority of airliners still contain insulation that burns. The board says that it applauds the improvements in insulation standards, but that they do not apply to most planes because the planes were built before the rules changed.

FAA officials say the insulation that remains in planes is not nearly as flammable as that on the Swissair jet. Removing it would be more dangerous because the removal process could damage planes. Such an effort would cost hundreds of millions of dollars for little benefit, they say.

Another recommendation was designed to help pilots determine a fire's location and severity. Other than in engines, below-deck cargo holds and restrooms, planes do not have fire detectors. The swirling air currents within a jet can make locating the source of smoke difficult.

About four minutes passed on Swissair Flight 111 from the first indication of smoke until the two pilots realized they had a fire. More time passed before they determined where it was located. A swifter reaction might have given them a chance to put out the fire.

But John Hickey, the head of the FAA's aircraft-certification division, says detectors may not enhance safety. Hickey says that detectors could lead to false alarms or give crewmembers a misleading idea of where a fire is located.

Officials at Boeing, which built most of the world's airliners, agree.

They say that adding detectors could also damage aircraft, particularly fragile wiring. It's better to prevent fires in the first place, they say. Adding detectors would also cost millions of dollars.

Regulators also have balked at making less costly changes.

Prompted by the Delta fire and other incidents, the NTSB two years ago issued several safety recommendations calling for improved firefighting training and equipment. Earlier this year, the FAA issued guidelines to airlines that call for better training and for flight crews not to hesitate in using Halon extinguishers.

But the FAA did not mandate the additional hands-on training the NTSB sought. Flight attendants must put out a real fire during their initial training but never have to do so again.

The NTSB wants attendants to perform periodic exercises that realistically train them how to find and put out hidden fires.

The FAA also balked at requiring the types of extinguishers that work best against hard-to-reach fires.

FAA tests show that Halon extinguishers with flexible hoses are far more effective against fires in tight spaces than extinguishers with rigid nozzles. The FAA recommends that airlines use models with flexible hoses, but officials say they see no need to require them. Many airlines use the less desirable models, according to the Air Transport Association, the airlines' trade group.

Finding hidden fires

In aged jets and sooty warehouses that smell of burnt plastic, the FAA is trying to find ways to make planes safer from fires.

Brian Meisenhelter, a technician at the FAA's Fire Safety Branch near Atlantic City, is part of a team trying to find a solution to a problem that has cropped up in several incidents: Fires burning in hidden areas are sometimes impossible to reach.

As a demonstration, Meisenhelter lights six candles to simulate a fire in the cramped attic area of a Boeing 737. He slips the ceiling panel back in place.

If the flames were on a real flight, the crew would be in trouble. Removing the ceiling panels is difficult, and tools that could cut through the panel are not allowed for security reasons.

During the demonstration, Meisenhelter lifts a red Halon extinguisher about the size of a wine bottle. He jams the extinguisher's hose into a hole in the ceiling and squeezes the trigger. As excess Halon dribbles onto the floor, a cloud of the chemical fills the small space above. The Halon smothers three of the six candles those within 3 feet of the opening. The three candles farther from the opening continue to burn.

Tim Marker, who oversees the FAA project, says that creating small holes in the ceilings of narrow-body jets like the 737 shows promise as a way to fight fires that otherwise couldn't be reached.

But the experiment also illustrates the difficulties in making fire-safety improvements. Tests on wide-body jets were not as successful. The space in the attic is too large and the extinguishers too small to put out fires, Marker says.

Officials with Boeing are skeptical the system would work on any jet. Without a way to determine where a fire is located, flight attendants might shoot extinguishers into the wrong holes, they say.

Nearly every proposed improvement faces the same difficulties: questions about practicality, development that could take years and the potential that the fix could create harmful unintended consequences.

Hickey says he is wary of proposals that require extensive work in the delicate innards of planes.

"I've got to guard against knee-jerk thinking that at a basic intellectual level seems like a panacea. Often many of them have other consequences," Hickey says.

Hundreds of incidents

Fires aboard airline flights are common. More than 1,000 smoke or fire incidents on airline flights were reported to the FAA in 1999, according to a study by the Air Line Pilots Association, the nation's largest pilots' union. Of those, 359 prompted an unscheduled landing the equivalent of about one per day.

But most of the incidents turned out to be minor, such as false alarms or food smoldering in an oven. Serious fires occur far less often, perhaps only a few times per year. Fatal accidents are even rarer.

But fire is one of the few safety hazards in aviation that pilots and flight attendants may be powerless to fight. Unions representing flight attendants and pilots say they are handicapped by a lack of tools and training.

"It doesn't happen that often," says Capt. Tom Phillips, a fire expert with the pilots association. "But when it does, we would feel that much more comfortable if we had a detection system. If we don't really know what we have, then we don't know what we may need to do just to get the plane down quickly."

After 23 people died in 1983 on an Air Canada jet that caught fire and made an emergency landing in Cincinnati, United Airlines held an exercise to see what would happen if a fire broke out on one of its jets.

Edmond Soliday, the former head of safety for United, put pilots in a flight simulator and told them to re-create a flight across the Atlantic where it's impossible to make an emergency landing. The pilots worked with members of United's engineering department to locate the fire and put it out. But the fire moved too quickly. They lost the jet, Soliday recalls. "To me, that is the most dangerous event on an airplane," he says.




from this link
NTSB Identification: NYC99IA231 .
The docket is stored in the Docket Management System (DMS). Please contact Public Inquiries
Scheduled 14 CFR Part 121: Air Carrier DELTA AIR LINES
Incident occurred Friday, September 17, 1999 in COVINGTON, KY
Probable Cause Approval Date: 5/9/2001
Aircraft: McDonnell Douglas MD-88, registration: N947DL
Injuries: 118 Uninjured.

On departure climb, the flight attendants smelled something burning. Then a passenger noticed a 'glow' in the right side air vent near his feet and reported that the cabin floor was warm. Halon was sprayed into the vent, and the glow disappeared. The pilot declared an emergency and returned to the departure airport. The airplane was stopped on the runway and based upon reports from emergency personnel, an emergency evacuation was performed. Thermal damage and sooting was found on the right side underside floor structure, a nearby fiberglass bin wall panel, and a potable water bottle. A 5-foot by 5-foot area of insulation, which consisted of fiberglass, covered on both sides with a metallized mylar, was burned. The right side, alternate static port heater lay under the insulation. The insulation on one of the wires leading to the heater was found to be deteriorated and melted where it was bent around the thermostat case. Evidence of metal transfer was found between the solid-core wire and the adjacent heater case. Soot was found on the insulation covering the wire and adjacent heater case. The heater was manufactured with the wire bend.

The National Transportation Safety Board determines the probable cause(s) of this incident as follows:

Deteriorated wire insulation and shorting at a short radius bend to the electrical wiring in the right side alternate static port heater, which resulted in electrical arcing and a fire sustained by overlaying thermal acoustic insulation.

from this link


On September 17, 1999, about 2230 eastern daylight time, a McDonnell-Douglas MD-88, N947DL, operated by Delta Air Lines (DAL) as flight 2030, performed a precautionary landing at the Cincinnati/Northern Kentucky International Airport (CVG), Covington, Kentucky. There were no injuries to the 2 certificated airline transport pilots, 3 flight attendants, and 113 passengers. The airplane received minor damage. Flight 2030 was operated on an instrument flight rules flight plan under 14 CFR Part 121.

Flight 2030 was a scheduled flight between Covington and LaGuardia Airport (LGA), Flushing, New York. The airplane was pushed back at 2150, and was airborne at 2201. At 2214, as the airplane was climbing through FL230 (23,000 feet), the flight crew reported that there was smoke in the cabin and declared an emergency. According to the captain's written statement:

"...Shortly after takeoff the flight attendants reported a 'funny smell' in the cabin and described it as 'sulfurous'. This was quickly followed by a report of the fumes growing stronger and smoke. An emergency was declared and the aircraft was turned back to CVG. The first officer continued to fly the aircraft and I initiated the Smoke Identification/Removal checklist in the Pilot's Operating Manual."

"During the descent, the flight attendants reported a 'glow' coming from the floor grille near the sidewall in the vicinity of seat 11E. At least one halon extinguisher was discharged in the direction of the glow. Shortly after, the flight attendants reported that smoke seemed to be dissipating."

"The landing was performed on runway 18L in CVG. Fire crews immediately met the aircraft, and reported smoke and signs of a fire in the forward cargo bin. A passenger evacuation was performed."

Interviews with the flight attendants disclosed that the smoke was in the forward portion of the coach class cabin. Passengers were moved away from the area, and as one passenger moved his bag, one side was observed to be "scorched." A flickering red glow was observed coming from the floor vent. While one flight attendant went to the cockpit to notify the captain what had been seen, another flight attendant sprayed the contents of a halon fire extinguisher into the vent, after which the red glow disappeared.

Examination of the airplane revealed that the interior framework of the fuselage was covered with insulation referred to as thermal blankets. The blankets were separated by the ribs of the fuselage. The insulation consisted of fiberglass, overlaid by a layer of metallized Mylar coating on each side. Examination of the insulation in the vicinity of the right side alternate static port heater revealed that the metallized Mylar covering over the fiberglass had burned away in a 5-foot by 5-foot area, with the edges of the Mylar charred. The damage consisted of sooting, and heat distress to the underside floor structure and a fiberglass potable water bottle. A nearby fiberglass cargo bin wall panel was also burned. In addition, in the cabin, soot damage was visible on the right cabin sidewall in the vicinity of passenger row 11.

The heating element for the primary and alternate static source heaters was controlled from a rotary cockpit switch, which could be activated on the ground or in the air. All heaters were activated together. The rotary function of the switch was used to measure current draw for each heater. A thermal sensor on each heater regulated the temperature of the heating elements within pre-determined limits. In addition, there was a thermal fuse for each heater, and a circuit breaker located in the cockpit, that had not tripped.

According to DAL personnel, the right side, alternate static port heater was still operational when the airplane was ferried to Atlanta for further maintenance.

According to the Safety Board Airworthiness Group Chairman's report, examination of the heater revealed the resistance of the insulation was 0.05 megaohms, instead of the specified 40 megaohms. Examination of the "A" wire revealed the thermofit wire tubing, which encased the solid-core copper wire was melted and eroded where the wire was bent around the thermostat housing, prior to reaching the thermal fuse. In addition, the insulation had also rubbed against the thermostat housing, and was melted in some areas. The internal wire was also eroded in the same area. Sooting was found on the thermostat case, and the potting compound adjacent to the case. Metal transfer had taken place between the solid-core wire, and the adjacent heater case.

DAL conducted a fleet wide examination of their MD-88/MD-90 fleet to ascertain the condition of their static port heaters. Eight heaters were found with evidence of thermal damage on their wires and or connectors.

As a result of this occurrence, and their fleet wide inspection, DAL removed all Mylar covered insulation blankets from around the primary and alternate static port heaters on their MD-88/MD-90 fleet.

The party representative from DAL reported that they did not track the serial numbers or time on the heating units. The date stamp on the right side alternate static port heater was prior to the airplane's delivery date to DAL. The part was not life limited. The airplane had accumulated 28,033 hours and 22,934 cycles since new, at the time of occurrence.

According to the party representative of Electrofilm, the position of the wire that had deteriorated insulation on the incident heater was as manufactured. He further reported that the manufacturing process had been changed, and the wire rerouted to reduce the bends induced by manufacturing.

Initial reports from the Federal Aviation Administration (FAA) and DAL indicated no injuries received during the evacuation. Several months later, the Safety Board received information that there had been injuries sustained during the evacuation.

from this link


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