By Jared Chausow
By Katie Toth
By Elizabeth Flock
By Albert Samaha
By Anna Merlan
By Jon Campbell
By Jon Campbell
By Albert Samaha
It was no surprise that the NTSB's technical staff had decided that the event that tore apart the Boeing 747 and sent 230 people to their deaths over the ocean eight miles south of Long Island was "an explosion of the center wing tank resulting from the ignition of a flammable fuel/air mixture. The source of ignition could not be determined with certainty." Yet the NTSB had not succeeded in papering over the cracks in its investigation. During two days of discussion, at August 22 and 23 board meetings, the NTSB staff . . .
The splatter issue is one more anomaly in an investigation that has shrugged off many. On the 22nd, in answer to a board member's question, NTSB director of aviation safety Dr. Bernard Loeb admitted that some investigators had questioned what could be the source of the brown specks of spongy material. Tests determined that temperatures above 490oF had melted plastic foam insulation from around an air-conditioning duct that runs fore and aft outside the tank, over the top of the left side of the tank roof just below the passenger cabin floor. After extensive analysis, Loeb said, "We determined it was fully consistent with the scenario we have given you [i.e., with the breakup of the center wing tank]."
But the "Splatter Deposits Study," a never released report obtained by the Voice, appears to challenge Loeb's statement. The report says the melted foam was splattered over an eight-foot-long section of the tank roof and inside the shattered air-conditioning duct. The splatter was thrown forward with enough force to break through the roof of the tank, landing on two fragments of the front spar (between the wings and under the seats) that were ejected very early in the breakup sequence.
Splatter was also found on the fuselage and floor structure just in front of the front spar, and on passenger seats above. The investigators "explored possible airplane sources of higher than normal heat incoming to the area of the splatter," and found none.
In introducing its own endeavors, the NTSB in Washington ignored existing research into Jet A aviation kerosene. "Basic information was not available when we began," said Dr. Joseph Kolly, an NTSB engineer.
Kolly's statement was baffling, because in fact there is a wealth of data on the flammability characteristics of aviation fuels, including Jet A, available in studies published by the navy, the air force, and a body called the Coordinating Research Council. Many of these studies are even referenced by the NTSB in its reports. For some reason, though, the NTSB felt compelled in Washington to present its own prolific work on Jet A as groundbreaking.
Some of the claims Kolly made for that work do not stand up under scrutiny. For example, when he displayed a slide illustration showing temperatures recorded at many locations inside the center tank of a 747 used for a so-called TWA 800 Emulation Flight test, it was noticeable that none of the temperatures recorded at the altitude at which the plane exploded were below 110oF. But temperatures that appear in the published version of that illustration are as low as 101oF. Kolly said "the average high temperature" inside the tank at the altitude of the explosion was 120oF. But the average inside the tank, going again by the NTSB's published figures, was actually 111.5oF.
These temperatures are significant because they are central to the NTSB case that the center tank exploded and caused the accident. Lacking any evidence of an ignition source, the Safety Board did the flight test and other tests to show that the atmosphere inside the tank, with possibly 50 gallons of fuel, was flammable.
But even if a flame is produced, that does not necessarily mean an explosion will follow. "The mere existence of a normal flame does not by itself imply the beginning of an explosion," notes a NASA addendum to the NTSB's Systems Report.