Wing flaps failed on the Spanair flight that crashed last month, killing 154 people, and an alarm that is meant to warn pilots of the problem never sounded, investigators said yesterday.

They did not say whether they believe the flap malfunction caused the August 20 crash that killed all but 18 people on the MD-82. They offered no theory on what triggered Spain's worst air disaster in 25 years.

Investigators also said they needed to study further a faulty air temperature gauge outside the cockpit, a problem that forced the pilot to abandon a first take-off attempt and that Spanair has described as a minor glitch. The plane crashed about an hour later during its second attempt to take off.

The findings were drawn from the flight data and cockpit voice recorders which showed no evidence of problems with the engines.

The investigation found wing flaps, which provide extra lift during takeoff, failed to extend. But the pilots were unaware of the problem because the cockpit alarm did not go off.

Meanwhile, Russian media reported that the pilot of the Aeroflot jet that crashed killing all 88 people on board ignored commands from air traffic controllers.

Officials blamed a faulty engine for the crash on Sunday of the Boeing 737-500 in Perm.

Flight controller Irek Bikbov said the pilot was disobeying orders to descend on the final approach and instead taking the jet higher.

"He confirmed he was going down but kept climbing," Bikbov said.

"He was behaving in a strange manner and wasn't following my orders," he added. The last thing controllers heard was a scream in the cockpit seconds before the crash.