Crashed Turkish Airlines Boeing had faulty altimeter

Dutch accident investigation council chief Pieter van Vollenhoven said their initial findings showed that the left altimeter of the crashed Turkish Airlines Boeing 737-800 had failed. The auto-pilot thus throttled back and flew the plane too slowly.

Van Vollenhoven based this initial finding on the data from the retrieved flight-data recorder, the black box, of the plane after the crash last Wednesday. This showed that the Turkish Airlines Boeing 737-800 which crashed in its approach to Schiphol airport was flying too low and too slowly by the time it approached to land on the Polderbaan runway. It was flying on autopilot at 9,150 feet on its approach to the Polderbaan runway -- but the left sided altimeter was measuring their height at minus 8 feet. Only the left altimeter had failed. The right handed side one worked perfectly, he said. Altimeter failed twice before This failure and the accompanying caution alarms 'may not have been considered a problem by the Turkish airline crew' , he noted, as 'they kept flying on autopilot' . Automatic warning signals - such as severe shaking of the steering column -- were also given off at 150 metres but by that time, it was too late for the crew to respond adequately: the plane by then was flying so slowly that it dropped one kilometre before the landing and crashed into the farmer's field. The black box showed that this left altimeter had failed twice on previous flights of this specific aircraft. An altimeter this bounces radio-signals off the ground and reads its exact height. above the surface This plane has two such meters. The left radio-signal altimeter had failed while the plane was being landed on auto-pilot and thus the auto-iloted plane also took back gas and automatically reduced its air speed. That's why Flight 1951 crashed at 10.31am last Wednesday in the water-logged plowed field. The wreckage now will be cleared away and taken to another location. Warning to Boeing This investigation council does not establish any kind of guilt - they only examine what may have happened, he said. One warning he gave to Boeing airline company however was that they may want to change their manual for the Boeing 737-800. This states that whenever the altimeters do not work, the autopilot and automatic fuelline facilities may not be used . He said the the company 'may want to reanalyse this instruction to its pilots.' Van Vollenhoven said this particular aircraft's same left altimeter had also failed twice during eight previous flights: this had been determined from the information gathered from the black box - but all this information is also still being analysed and the council's final report would contain all this information in its final report. They are still analysing all these details of this particular Boeing, but also of others of the same 737-800 type, to establish whether this could be a structural, mechanical failure or is caused by other problems such as maintenance, he said. "It s measurements show suddenly measured differences in height from 180 feet to a sudden minus 8 feet on the faulty left- altimeter -- and this caused the plane to immediately take back gas, which caused an immediate reduction in speed and height. The plane was by then flying too slowly to continue its momentum and crashed.' Turkish pilots did not respond to altimeter alert: He said the initial findings determined that Polderbaan runway approach also had a thin layer of low-lying fog which made it difficult to see for pilots flying in manually. The Turkish pilots were using autopilot and did not spot the warning pertaining to the faulty altimeter in time to take it off autopilot and steer the plane themselves. During the crash nine people died and a large-scale rescue operation rushed 80 people to surrounding hospitals. At the moment, 28 injured people still remain in hospital - one is critical. Van Vollenhoven said an independent judicial investigation is still probing whether there was any criminal culpability in this crash. His council was not involved in determining 'guilt'. Recorded by Adriana Stuijt from press conference.