By JOHN J. GOLDMAN and ERIC MALNIC, TIMES STAFF WRITERS
NEW YORK - In the FBI's strongest statement since TWA Flight 800 plunged into the Atlantic Ocean last summer, FBI Director Louis J. Freeh said Sunday that mechanical failure and not terrorism was the likely cause of the crash that killed all 230 people on board.
"I think that the evidence as we have developed it to date, and particularly the evidence we have not found, would lead the inquiry toward the conclusion that this was a catastropic mechanical failure," Freeh said.
"...The evidence is certainly not moving in the direction of a terrorist attack," he added during an appearance on NBC-TV's "Meet the Press." "It is in fact moving in the other direction."
Freeh's remarks seconded the opinion of the National Transportation Safety Board, which late last year reached the tentative conclusion that the Boeing 747 jumbo jet disintegrated because of an explosion, probably caused by static electricity or a spark in its center fuel tank.
Sources close to the investigation stressed Sunday that Freeh's remarks were not based on any startling new findings.
"What prompted his remarks was his appearance on television," one of them said. "There's absolutely no new information, no 'Eureka.'"
What Freeh's comments reflect, they said, is a growing consensus, based on months of painstaking investigation, that because there is no evidence of a bomb or a missile, mechanical malfunction of some kind is the logical cause of the explosion that brought down the plane.
Freeh's remarks also shift the burden of the investigation, once and for all, squarely onto the shoulders of the NTSB. The FBI has been pursuing the criminal aspects of the joint investigation—possible terrorism or sabotage—and Freeh's acknowledgement that neither apparently was involved leaves the NTSB clearly in charge of what has been, at times, an awkward partnership.
As he has all along, NTSB Vice Chairman Robert Francis on Sunday minimized any differences between the two agencies.
"This investigation has been, and continues to be, an unparalleled cooperative effort on the part of both agencies," Francis said in a prepared statement. "The FBI's leadership and expertise continues to be of extraordinary value to the investigation."
Investigators say the plane had less than its full capacity of passengers when it took off from New York's John F. Kennedy International Airport July 17 on the way to Paris. Its center fuel tank was almost emtpy—prompting the theory that fuel fumes and air in the tank could have mixed at just the right ratio to form a disastrously combustible mixture.
But FBI and NTSB investigators have been unable to confirm the theory. Highly sophisticated tests are underway to try to prove the thesis beyond a reasonable doubt.
Freeh stressed Sunday that neither agency can yet state definitively that the plane crashed because of a massive mechanical problem.
"We have not made that conclusion," the FBI director said, "nor has the safety board, which is the agency responsible for the case.
"We want to spend a little more time doing our evaluations. We have just done a top-to-bottom reevaluation with the safety board. We need to get a conclusion...
"We have to get some closure as to this case... We're hopeful by the mid-to late summer we will be able to make some specific conclusions in conjunction with the safety board," Freeh added.
The NTSB has tentative plans to hold public hearings into the crash in late summer or early fall.
Freeh's comments were echoed Sunday by James K. Kallstrom, assistant director of the FBI in charge of the bureau's New York field office, which started conducting an extensive criminal investigation the night the plane crashed.
"I believe it is less likely at this point that it was a bomb or a missile or a criminal act, but we can't say for sure," Kallstrom said on "News Forums," a local TV public affairs program.
"We have looked at every hole, every rip, and we see no evidence of high explosive. We see no evidence of a piece of shrapnel from a missile or warhead going through the plane," Kallstrom said.
Navy divers, commercial trawlers and salvage vessels have found 95% of the aircraft, in one of the largest underwater recoveries in the nation's history. Last week, it was announced that trawling would stop because investigators believe that all significant portions of the plane have been pulled from the ocean.
Experts working in a huge hangar in Calverton, N.Y., near the crash site, have reassembled 92 feet of the middle of the plane in what NTSB officials say is the biggest reconstruction in the history of aviation accident inquiries.
NTSB investigators and FBI agents are studying the midsections to be sure no holes exist characteristic of a missile strike. So far, none have been found.
Kallstrom said efforts were underway to "explain every hole in the plane and light in the sky."
"I want to leave no stone unturned, look at every possible way we can look at it and then reach a conclusion," he added.
On the night the plane crashed, scores of witnesses have said they noted streaks of light in the sky that FBI agents initially believed could have been the signature of a missile. But these descriptions have not been confirmed by radar tapes and satellite data. Investigators say the witnesses might have seen part of the explosions that shattered the plane.
A central thrust of the NTSB's inquiry has been finding the source of a spark that could have ignited the jet fuel in the almost-empty tank.
Much of the attention has been focused on the 747's cross-feed manifold—a fuel line running through the center tank that connects the two other fuel tanks in the wings.
One there is that the line's O-rings—which connect the segments of pipe that form the line—had become old and distorted. This, in turn, might have caused grounding problems that could have allowed static electricity travelling along the manifold to discharge into the tank, which apparently contained a highly volatile mixture of fuel vapor and air at a temperature conductive to ignition.
Late last year, the NTSB recommended that the Federal Aviation Administration order urgent design changes in the center fuel tanks of hundreds of jetliners, including all 747's.
The changes, aimed at precluding the buildup of volatile fuel-air mixtures at temperatures that would permit ignition, included adding insulation around heat-generating equipment, filling center tanks shortly before takeoff with fuel that has been kept cool, keeping tanks full enough to prevent substantial vapor buildup and installing sensing devices that would warn crews of dangerous fuel-tank temperatures.
More recently, the NTSB convened a meeting of experts in the Calverton hangar and at a nearby hotel to study the properties of jet fuel. The experts were asked to try to determine under what conditions fuel mixed with oxygen would ignite.
What emerged from the conference was the realization of just how complicated a problem the experts faced.
The center fuel tank, where the explosion occured, was divided into several sections, an investigator explained to The Times. Within these seperate compartments, fuel and air can have different mixtures and different explosive potentials.
Adding to the difficulty, fuel from both Athens and New York was pumped into the tank at different points during the plane's travels. Investigators said subtle differences exist between U.S. and European jet fuel, which further complicates the inquiry.
During his TV interview, Freeh strongly denied that Flight 800 was struck by mistake by a U.s. military missile—a position that Pierre Salinger, President Kennedy's former press secretary, and other conspiracy theorists have advocated.
Goldman reports from New York and Malnic from Los Angeles.