Wed Mar 4, 2009 11:04am EST
By Catherine Hornby
THE HAGUE, March 4 (Reuters) - A malfunctioning altimeter contributed to the crash of a Turkish Airlines flight last week at Amsterdam airport, said Dutch authorities, who issued a warning to the plane's maker Boeing.
When flying at about 1,950 feet (594 metres) the plane's left radio altitude meter indicated the Boeing 737-800 was flying at minus 8 feet, prompting the automatic pilot to shut down the engines, the Dutch Safety Board said on Wednesday.
"The crew initially did not react to these events," Dutch Safety Board head Pieter van Vollenhoven told reporters.
When an alarm went off that the plane's speed would drop below the minimum, the pilots reacted and reignited the engines.
"But the plane was too low at 150 metres. As a consequence the plane crashed 1 kilometre before the runway," said Van Vollenhoven.
Five Turks and four Americans were killed when the Boeing plane plunged into a field short of a runway while trying to land last week at Schiphol, Europe's fifth-largest airport by passenger numbers and third largest by freight volume.
Among the dead were three pilots and a flight attendant. The plane carried 127 passengers and 7 crew, of whom 28 are still in hospital.
"We are focussing the investigation on the malfunctioning radio altimeter and its consequences. Whether there could have been a different reaction will take more time to find out," Van Vollenhoven said.
"The reason to go public now already is to warn Boeing and all users of this plane type that vigilance is required with regards to the altimeter," he said.
Boeing said in an statement it was "issuing a reminder to all 737 operators to carefully monitor primary flight instruments during critical phases of flight".
The plane initially hit the ground in a boggy field with its tail followed by its undercarriage, with a forward speed of 175 km per hour on impact. An aircraft should normally have a speed of 260 km per hour for landing, the safety board said.
Braking caused by the ground meant that the aircraft broke into two pieces. Most of the fatally wounded were near the rupture, in business class, and the three crew members in the cockpit died as a result of the enormous braking forces.
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*Additional reporting by Gilbert Kreijger in Amsterdam, and Bill Rigby in Seattle; Editing by Louise Ireland
I do not fly a 737 but maybe somebody who does could please explain how a faulty rad alt will cause the engines to shut down? Seems crazy to me! 