American Says Heated Oil Caused Smoke on Flight

Air Safety Week, August 18, 2008

American Airlines says that oil residue heated by an engine caused one of its Honolulu-bound Boeing 757s to make an emergency landing Aug. 5 at Los Angeles International.

The jetliner was evacuated at after indications of a fire in the passenger cabin. There were no injuries among the 188 passengers and six crew members on Flight 31, which had just departed LAX for Honolulu., an American Airlines spokesman. The flight deck crew elected to turn around after someone smelled smoke in the cabin, but no sign of fire was found on the jetliner using thermal imaging cameras that scanned the cabin and cargo hold.

The captain elected to declare an emergency and get everybody out of the aircraft via the emergency slides. American, the National Transportation and Safety Board (NTSB) and the Federal Aviation Administration (FAA) investigated. The major air carrier said in a statement that "American Airlines has found that this was caused by oil residue being heated by the engine. At no point was the safety of the flight in jeopardy." American also said its review determined "that the flight crew acted appropriately in all instances onboard."

Meanwhile, the FAA is reviewing the reported failure of dozens of emergency oxygen masks during the flight emergency. FAA officials are looking into concerns that some masks for passengers did not deploy during the incident while others failed to provide oxygen.

The Los Angeles Times quotes an FAA spokesman as saying "We take reports like this very seriously. The FAA is working closely with American to determine what the problems are, why they happened, and to make sure the problems are fixed."

Problems with deployment of Boeing 737-800 passenger emergency oxygen masks is also under investigation.

A scheduled Qantas flight from Hong Kong to Melbourne, Australia had to make an emergency landing in Manila on July 25, when an exploding oxygen cylinder blew a large hole in the fuselage of the Boeing 747-400 (VH-OJK), prompting the jetliner to lose cabin pressure.

All 346 passengers and 19 crew aboard Qantas Flight 30 were safely deplaned after landing in Manila.

A number of passengers reported that their oxygen masks appeared not to function correctly when they deployed from the overhead modules.

Australian Transport Safety Bureau (ATSB) investigators found that most of the oxygen masks deployed correctly from the passenger modules and had been pulled to activate the flow of oxygen to the mask. Inspection by the ATSB shows that 484 masks had deployed, that is, dropped from the ceiling. Of those, 418 had been activated by pulling on the mask to activate the flow of oxygen. A small number of masks did not deploy from the passenger modules. Investigations into this aspect of the accident are continuing.

The investigation team is still examining the oxygen system, including liaising with the manufacturer to determine if the flow of oxygen was adequate for the five and a half minute descent to 10,000 feet, where the masks were no longer required.

The FAA has been concerned for some time about oxygen mask failures aboard Boeing 757s and 737s. In May 2007, the aviation agency issued an airworthiness directive ordering carriers to inspect oxygen masks on those planes and correct any problems. The directive affects about 815 of the jetliners

FAA officials issued the order after receiving information that oxygen generators had failed during in-flight depressurization. The FAA blames components that fracture between the oxygen masks and the release pins that activate the flow of air.

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