Sixteen years before TWA Flight 800 exploded with a loss of 230 lives in 1996, a Boeing study showed that the central fuel tanks of its jumbo jets were taking in heat from air-conditioning units directly under them, but the company failed to report the finding to safety investigators until last summer, federal and company officials acknowledged yesterday.
In its 1980 study, Boeing found that "the dominant source of heating" in the central fuel tanks of its E-4B aircraft -- a military version of Boeing's commercial 747 -- was the air-conditioning equipment bay, positioned right under the fuel tank. But the study was not given to TWA 800 investigators until June of this year.
Federal officials, confirming a report on the study in the Washington Post yesterday, said it was unclear whether knowledge of the four-volume 1980 Boeing study might have aided the inquiry into the fiery end of the 747 jetliner off New York's Long Island on July 17, 1996.
But they said the relevance of the Boeing study should have been determined by federal investigators, who have generally concluded that vapors in the central fuel tank of TWA 800 exploded, although the source of ignition has not been determined.
The National Transportation Safety Board has expressed dismay over Boeing's failure to report its findings to investigators until three years after the disaster, and said in a statement that it would consider the Boeing findings in drafting its final report next spring.
Iowa Republican Sen. Charles E. Grassley, who is the chairman of a subcommittee that oversees airline disasters and has held hearings on the investigation of the Trans World Airlines explosion, went further, contending that the TWA 800 tragedy might have been prevented if Boeing had reported its findings after the 1990 explosion of a center fuel tank on a Boeing 737 jet in Manila, Philippines.
In a statement, the senator said: "The government and the manufacturers need to have an ethic that overreporting is better than underreporting. This was too important to fall through the cracks."
Steven Pounian, a lawyer on a plaintiffs' committee representing many of the families of the victims of the TWA 800 explosion, also criticized Boeing for not reporting its findings earlier, and said the Boeing report would be used as evidence in lawsuits filed against the company.
Boeing spokesman Russ Young acknowledged yesterday that the company had not reported its findings to safety investigators until June, but said the failure had not been intentional. He questioned the relevance of the findings for the TWA 800 investigation.
"In retrospect, the whole report doesn't appear to be relevant to the NTSB investigation of the 747," Young said. "But it is unfortunate that it was not identified earlier and provided to the NTSB. Quite simply, the report escaped notice of the commercial airplane employees who had been working with the accident investigators."
Young said Boeing had changed its procedures for locating potentially relevant information in accident investigations, particularly information about military aircraft that might be applicable to commercial aircraft investigations.