Crash investigators look at turbulence from 2nd plane
NEW YORK (CNN) -- Wake turbulence from a second plane could be the culprit that snapped the tail from an American Airlines jet as it took off from a New York airport, costing the pilots control of the aircraft and sending it on a steep dive into a Queens residential area, investigators said Thursday.
All 260 people aboard American Airlines Flight 587 perished when the plane crashed early Monday into the Rockaways, a tight-knit beach community in southern Queens. Five people on the ground are still missing.
"There were no marks on the fin section or the rudder," National Transportation Safety Board member George Black told CNN. "We haven't found any other evidence of any impact with any foreign object. It appears to be some sort of aerodynamic effect."
A Japan Air Lines 747 was cleared for takeoff "about 2 minutes and 20 seconds" before the American Airlines flight, but actually took off 1 minute and 45 seconds ahead of Flight 587, National Transportation Safety Board Chairman Marion Blakey said Wednesday. Federal Aviation Administration regulations require 4 nautical miles, or two minutes, of separation between departing flights.
"The vortices do not disappear immediately after the airplane passes," Black said. "They linger in the air and drift with the wind and sink. A preliminary look at the strategic positions of these two airplanes would imply that the vortices from the 747 would be in the approximate area of the track of the American Airlines airplane."
When asked if the wake effect could have sheared off Flight 587's tail, Black said investigators "just don't know yet."
"We did extensive wake turbulence testing on the Pittsburgh USAir 427 accident several years ago," he said. "And we have the people who worked on that accident here. We will be applying that knowledge and probably doing some testing to determine the strength of a vortex from a Boeing 747-400, which was the Japan Airlines airplane."
Black also said the Airbus A300's maintenance records will be reviewed as part of the investigation. An FAA incident report shows the same plane that crashed Monday experienced severe turbulence over the Caribbean island of Martinique in 1994, when 46 passengers and flight attendants were injured.
The jet took off for Santo Domingo in the Dominican Republic from John F. Kennedy International Airport shortly after 9 a.m. Monday, but remained aloft less than three minutes.
Black said investigators are wading through "a good wealth of data" contained on the flight data recorder after the manufacturer was able to fix a damaged memory module.
The recorder contains 81 hours of data that continue past the point where pilots lost control of the plane, "but ends before impact," Black said.
Black said investigators are looking to the data recorders, air traffic data and radar information -- along with eyewitnesses -- to try to piece together the mystery of the crash.
Investigators believe the tail section of the jet -- found in the waters of Jamaica Bay a 1/2 mile from the crash site -- sheared off shortly after takeoff.
Black said the fittings that hold the tail fin onto the fuselage were last inspected in December 1999. However, he noted that before delivery of the plane to American Airlines in 1988, the left center fitting was found to be faulty and was repaired and reinforced by the manufacturer.
American Airlines spokesman John Hotard said all 34 Airbus A300s in its fleet will be fully inspected, but none of them will be grounded.
Investigators said they had no evidence indicating Monday's crash was "anything but an accident," but also said they could not rule out sabotage.
'Wake turbulence' probed in crash of Flight 587
November 13, 2001
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