Cause for Turkish Airlines flight known: Dutch Safety Board issues warning

Last Wednesday, a Turkish Airlines flight crashed in a field just 1 kilometer short of the runway at Schiphol Airport in Amsterdam. The report as to what caused the accident has been released. After reading through it myself, and thanks to the paired down version of Gadling’s own Kent Wien, pilot and writer of Cockpit Chronicles, here are the details.

According to the report, there was a malfunction of one of the radio altimeters, the device that displays the distance of the airplane from the ground. The left altimeter, instead of reading the Boeing 737′s actual height at 1950 feet when the plane was descending, it read 8 feet.

At the point of the glitch, the auto-throttles went to idle because the reading said the plane was just above the runway thus about to land. This caused the plane to slow down more than it should have. The pilots didn’t have enough time to recover the speed needed to pull the plane out of a stall to a higher altitude in order to achieve a safe landing.

Along with determining the malfunction in the radio altimeter, the investigation also found out what happened to the plane upon impact. The tail of the plane hit first, then the undercarriage. When the plane hit the ground it was going at 150 kph. A normal landing speed is 260. Because the ground was soft, the plane had a “rapid halt” within 150 meters.

During landing, the tail broke off and the plane ruptured at the business class section which is where most of the fatalities and injuries occurred. Eighty passengers in all were injured and nine people died (4 crew, including the pilots and five passengers). The area of the plane around the wings was the most intact.

There are still investigations being made surrounding the altimeter’s malfunction and the Dutch Safety Board has issued a warning to Boeing.

For the report, click here. Prior to these findings, one theory about the cause of the crash was wake turbulence caused by a larger plane landing right before this plane’s attempt. (See article.)