By Steve Weinstein
By Rachel Kramer Bussel
By Tim Elfrink
By Sydney Brownstone
By Graham Rayman
By Graham Rayman
By Graham Rayman
By Nick Pinto
Leaving aside questions about possible fatal structural weaknesses, in which case even a Chuck Yeager couldn't have saved the plane, what would the pilots interviewed by the Voicehave done differently to control the craft? When the plane was first buffeted by wake turbulence, the retired pilot said, "I like to think I'd have gone to the rightthe wind was from the right." Such a move, he said, would have taken the plane through the turbulence to calm air, leaving enough air space to turn left again to avoid flying over the heavily populated areas of Brooklyn, thus following a standard noise-abatement departure from runway 31 L at Kennedy Airport. In fact, the Airbus did not turn after the first jolts from turbulence.
Other questions may yet assume importance in the investigation. For example, on one occasion an Airbus rudder did not respond properly. And there have been episodes in which software was suspected of causing catastrophic problems. Most notable is the crash of a Kenya Airways A310 whose engines inexplicably failed when the plane was only 200 feet in the air, moments after taking off from Abidjan in the Ivory Coast. All but 10 people onboard died. That accident happened in January 2000, yet is still shrouded in mystery. According to an article in the Kenyan Daily Nation, witnesses saw the plane "wobble" in the air before breaking up; some witnesses to Flight 587 also saw the plane wobble. The article quoted pilots who speculated that the Airbus may have had a software problem that sent uncoordinated signals to various systems. The aircraft had been in service 14 years, just a year longer than the A300 that went down in Queens.
The National Transportation Safety Board has not raised the question of a computer malfunction in the case of American Flight 587, and last week NTSB spokesman Ted Lopatkiewicz told the Voicethat the autopilot was switched off for the entire 103-second flight. But Airbuses in any case are highly automated, ironically in order to guard against misjudgments by pilots. A computer glitch would presumably absolve the pilots of blame for the crash.
Then there's the far-out crash scenario of sabotage, which has not been ruled out.
Last week, NTSB investigators focused on the visible evidence: the severed tail fin and the possibility that the non-metallic composite materials used in its manufacture had failed, and how that failure may have related to the wake turbulence the plane encountered.
The FAA wasted no time in issuing an order called an emergency airworthiness directive to airlines to inspect the tails of their Airbus A300 and A310 fleets. The order went out on Friday; by Tuesday, the Timesreported that American had finished the inspections. Schiavo, noting that the inspections can be "extremely cursory," said, "It's hard to see weaknesses in the structure with these inspections."
The inspections were, of course, too late for the Flight 587 Airbus, a plane that already had a history of problems with its tail fin. The Timeshas reported that repairs were made to strengthen the area where the fin, or vertical stabilizer, attaches to the fuselage when the plane was first delivered. Then in November 1994 the same aircraft came to FAA notice when it flew through severe turbulence near Puerto Rico, causing dozens of injuries and possible damage to the tail fin.
According to Alison Duquette, an FAA spokeswoman, the routine in such an incident is to conduct a one-time inspection of the systems and structures. "They look at it, basically, and if something's wrong, it's taken out of service and fixed," she said. We do not know what, if anything, American found when it examined the tail, or what action it took; the plane's maintenance records are now part of the NTSB investigation.
But it looks as if whatever was done, it was not enough. "Vertical tails just don't come off," said Bill Kauffman, professor of aerospace engineering at the University of Michigan and an air-safety activist. In the case of Flight 587, he said, "the implications are enormous. Either the [FAA's] certification or inspection process was faulty, and these are fundamental things." Kauffman said the crash appears to mark the first structural failure involving composite material. "This was the first major application of composites to a big chunk of structure, other than flaps or slats," he said.
Boeing now makes the entire tail section of its 777, which first went into service in 1995, out of composites. The company makes grandiose claims for its composites, which are plastics reinforced with carbon fibers: that they are as strong as metal, more resistant to fatigue, and easily repairable. But this is a relatively new material with, presumably, new ways of failingfor example, the composite is made in layers that can come unstuck in a process called delamination.
"When it comes apart, those problems are difficult to fix," said John Cataldo, formerly a crash investigator at the Naval Safety Center. "We had that on navy planes." Regarding Flight 587, he said, "I'd be suspicious of the previous damage." Indeed, it is almost unheard of for an aircraft to lose a tail just because of turbulence.
Pilots know they have to be wary of turbulence from large jets. Light planes are most at risk, but larger passenger aircraft are not immunethe Aircraft Owners and Pilots Association manual points to the example of a DC-9 that got too close to a larger DC-10 on takeoff, caught a wing tip on the ground, and cartwheeled, killing everybody aboard.