Preliminary report on Schiphol crash focuses on altimeter

Investigators into the crash of the Turkish Airlines Boeing 737 at Amsterdam Schiphol Airport have highlighted problems with the aircraft's radio-altimeter

The Dutch accident investigators have determined that the radio-altimeter fault had occurred on several of the nine previous flights by the Boeing 737 aircraft.

According to reports on Flight Global on two of the flights, which were retained on the digital flight data recorder (DFDR), the fault caused the autothrottle to enter retard mode and the throttles to close as they did on the accident flight.

Boeing recpmmends that the autopilot and autothrottle should not be used on approach, as they were on the accident flight,

The investigators also describe how the aircraft entered the glidepath from above rather than below, and only decelerated to the correct approach speed of 144kt at an altitude of 770ft. With the throttles at idle, the aircraft's speed subsequently fell to 110kt at 420ft and a last-ditch attempt by the crew to recover was unsuccessful.

Five passengers and four crew died in the Feb 25 accident