Wall Street Journal: Error With Flaps May Have Led
To Spanair Crash
"The pilots of a Spanair SA jetliner that crashed in Madrid last month failed to extend the aircraft's flaps before trying to take off, according to people familiar with the investigation, and a suspected electrical malfunction kept them from getting a cockpit warning about the danger.
Preliminary data obtained from a pair of so-called black boxes recovered from the wreckage of the McDonnell Douglas MD-82, which killed 154 people, indicate that both engines were working properly and there was no fire before impact, these people said.
But the flight-data recorder shows that the plane's flaps, movable devices at the rear of the wings that provide extra lift needed at takeoff, weren't extended, according to these people.
Usually, that would have triggered a loud horn in the cockpit alerting the pilots that the plane wasn't properly configured for takeoff.
In the last few days, investigators have focused on the theory that some sort of electrical defect or problems with circuit breakers prevented the horn from sounding, these people say.
According to one person familiar with the details, investigators also are looking into why the normal pre-takeoff checklist failed to pinpoint that the flaps hadn't been extended. One person familiar with the details said investigators, among other things, are looking into whether the cockpit crew was distracted or hurried through the check.
Crash investigators haven't released this accident scenario and it still could change as the probe continues. One reason the automatic cockpit warning horn didn't sound might have been because some of the airplane's logic circuits mistakenly sent signals indicating the MD-82 was already in the air. The horn is designed to give a loud warning -- but it operates only when the plane's systems show the aircraft is on the ground.
Loaded with tourists headed for the Canary Islands at the height of the summer travel season, the twin-engine jet barely lifted off the runway, veered off it and smashed its tail on the ground three times while traveling about 4,000 feet (1,200 meters) before breaking up in a fireball.
Investigators are looking into the role of a malfunctioning outside-temperature sensor, which mechanics apparently disabled before the tragic takeoff. The operation of the sensor itself is unlikely to have any direct impact on the plane's ability to fly, according to aviation safety experts. But the problem with the sensor may have been a signal of related problems affecting other electrical circuits.
One retired pilot familiar with the electrical circuits of the MD-80 family of aircraft said problems with the probe could have been a sign of related electrical problems affecting other circuits.
The plane's unusually nose-high attitude and the rolling motion of the wings described by eyewitnesses, according to this retired pilot, is consistent with handling characteristics of a takeoff without flaps.
WSJ.com