Air Transport World’s Australian correspondent Geoffrey Thomas is reporting that a Qantas 737-800 approaching Sydney on 7 April suffered a similar malfunction to the one implicated in the Turkish Airlines fatal accident at Amsterdam’s Schiphol airport on 25 February.
The ATW report available in full to its subscribers points out that Qantas operating procedures for its 737-800s require the pilots to keep a hands on position on the engine throttles when they are set to auto-throttle to guard against and correct any anomalous behaviour.
In the Amsterdam crash the Dutch accident investigator has already revealed that one of two radio altimeters on that jet suddenly read its height as being 8 feet below sea level, which is the airport’s altitude, rather than the 1500 feet at which it was flying, in turn fooling the auto-throttle system which assumed the jet had landed and shut down the engines with disastrous results.
The Qantas jet is reported to have been 100 feet above the ground just short of landing when one of the altimeters read 10 feet. The auto throttle was immediately disconnected to prevent any premature engine shutdown.
The airline reported the malfunction to the ATSB which has contacted its Dutch counterpart so that the Sydney incident can be taken into account as it drills deeper into the reasons for an incident in which the Turkish pilots were unable to regain control of their jet before it hit the ground.