A faulty altimeter shut down the engine of a Turkish Airlines flight before it crashed last week near Amsterdam airport, killing nine, Dutch authorities have said.
They said similar shutdowns had occurred twice before on the same aircraft and were overruled by the pilots. They warned its maker, Boeing, and any airlines using 737 models to be vigilant.
When flying at about 1,950ft (594m), the aircraft’s left radio altimeter indicated that the Boeing 737-800 was flying at minus eight feet (–2.4m), prompting the automatic pilot to shut down the engines, the Dutch safety board said yesterday.
“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 aircraft’s speed would drop below the minimum, the pilots reacted and reignited the engines.
“But the plane was too low, at 150m [492ft]. As a consequence, the plane crashed one kilometre before the runway,” said Mr Van Vollenhoven.
Boeing said in an statement that it was “issuing a reminder to all 737 operators to carefully monitor primary flight instruments during critical phases of flight”.
The aircraft’s black box – which can register 25 hours of flying time and in this case had covered eight flights – showed the problem had occurred twice previously during landings.
Five Turks and four Americans were killed when the aircraft plunged into a boggy field while trying to land last week at Amsterdam’s Schiphol, Europe’s fifth-busiest airport. Braking when the aircraft hit the ground resulted in it breaking into two pieces and the tail coming off.
Among the dead were three pilots and a flight attendant. Most of the fatally wounded were near the rupture, in business class, while the three crew members in the cockpit died as a result of the enormous braking force.
The section that remained most intact was around the aircraft’s wings.
The aircraft carried 127 passengers and seven crew, of whom 28 are still in hospital.
“We are focusing 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,” said Mr Van Vollenhoven.
A trainee pilot was flying the aircraft before the crash took place, Mr Van Vollenhoven said, but he declined to say whether this could have had any impact on the events.
Misty weather and low clouds meant the runway was not yet visible at the height at which the descent started. “I think the pilots did not see that a problem was occurring,” he said. – (Reuters)