The National Transportation Safety Board, investigating the August 1980 jumbo jet accident in Saudi Arabia that killed 301 people, said yesterday that the cargo compartment of the Lockheed L1011 may not meet federal fire-safety regulations.
The safety board's statement came in a late-afternoon recommendation to the Federal Aviation Administration that it re-examine its earlier finding that the L1011's cargo compartment meets the regulations.
FAA officials said that such a reevaluation is already under way, but that no decision has been reached.
Lockheed would not comment yesterday on the recommendation.
The accident that triggered the investigation is one of the strangest on record. A fire broke out on board the Saudia Airlines flight shortly after it left Riyahd. The crew elected to return to the airport and landed the plane safely. By the time rescuers reached the aircraft and opened it, all aboard were dead.
Sources have reported that the crew took an unusual amount of time deciding to return, then taxied to the end of a lengthy runway instead of halting as quickly as possible and ordering an immediate evacuation. Rescuers had trouble opening the doors.
The fire itself started in the cargo compartment, investigators discovered later. Smoke and ultimately flames penetrated the passenger cabin above. The exact source of the fire has never been revealed.
Federal regulations require that "a fire occurring in [the cargo compartment] will be completely confined without endangering the safety of the airplane or the occupants. . . ." In the case of the L1011, the method chosen was to choke the fire by depriving it of oxygen rather than to install fire extinguishing equipment. U.S. sources believe that the Saudia crewmembers manipulated the valves controlling airflow to the cargo compartment so that the fire was replenished several times as the plane returned to Riyahd.
However, the safety board said, preliminary tests at the FAA's technical center have shown that "a fire of sufficient intensity to penetrate the L1011's [cargo compartment] ceiling liner in less than one minute burned for more than 10 minutes after the compartment airflow was shut off."
Therefore the board recommended that the FAA either require detection and extinguishing equipment in the cargo compartment or change the liner material to assure that the fire would not penetrate the passenger cabin or endanger the airplane controls near the cargo compartment.
Th cost of such a change could not be determined.