NTSB: Cause of Queens crash still undetermined

One of the engines from AA Flight 587 crashed into a gas station.

By Beth Lewandowski
CNN New York Bureau

WASHINGTON (CNN) -- Investigators are not focusing on pilot error as the cause of last November's crash of American Airlines Flight 587, the National Transportation Safety Board said Tuesday, disputing reports about the investigation.

The New York Times and other newspapers have reported that the probe was focusing on human error in the crash, which killed 260 people on board the plane and five on the ground, but the NTSB said those accounts were wrong.

"Contrary to recent press accounts, the board has not ruled out either mechanical malfunction or structural defect as causing or contributing to the accident," the NTSB said.

Instead, NTSB sources said, investigators remain as perplexed as ever about what caused the rudder and tail fin of the Airbus A300-600 to fall off and the plane to plummet into a Queens neighborhood.

EXTRA INFORMATION In-Depth: AA Flight 587 crash

"Although the flight data recorder showed significant rudder movement during the last moments of Flight 587, it is not known what caused the movement -- whether it was either mechanically induced or pilot activated -- or what role, if any, the movement played in the separation of the vertical stabilizer," according to an official NTSB update on the crash investigation.

The NTSB will issue recommendations to airline pilots regarding rudder usage in the near future, which indicates the agency has serious concerns about what pilots are trained to do when they lose control of an airplane, government sources said.

Differences of opinion exist within the aviation community regarding rudder use during situations like what might have happened when Flight 587 encountered wake turbulence seconds before crashing.

NTSB investigators also are searching for flaws in the materials that comprised the Airbus' tail section, hoping to determine whether those substances could have been responsible the rudder and fin separating from the rest of the aircraft.

Soon to begin are more extensive, destructive tests of the tail section at NASA Langley Research Center in Hampton, Virginia. Investigators said they are also surveying salvage yards for an intact Airbus A300-600 tail section for comparisons.