Faulty automatic throttle eyed in Indonesia jet-crash probe

The device reportedly had problems on previous flights

JAKARTA, Indonesia — Indonesian investigators probing the Jan. 9 crash of a Sriwijaya Air flight are looking at the possibility that a malfunctioning automatic throttle could have led to the pilots losing control, according to a person familiar with the investigation.

The autothrottle was producing more thrust in one of the Boeing Co. 737-500’s two engines than the other shortly before the plane carrying 62 people crashed into the Java Sea, said the person, who isn’t authorized to discuss the matter publicly. The device had been having problems on previous flights, the person said.

Issues involving the autothrottle on the 737 have led to incidents in the past, and a similar malfunction on another aircraft model was a cause of a fatal crash in 1995 in Romania.

Nurcahyo Utomo, the lead investigator at Indonesia’s National Transportation Safety Committee, confirmed that a malfunctioning throttle was “one of the factors that we are looking at, but I can’t say at this point that it’s a factor for the crash or there was a problem with it.”

Utomo’s team is working with engineers from Boeing to review the data from the aircraft’s flight-data recorder that was retrieved from the seabed last week. Rescuers are still trying to locate the memory module of the plane’s cockpit-voice recorder, which broke apart upon impact.

Unequal thrust from the engines can cause a plane to turn or even roll onto its side and descend abruptly, if it’s not handled properly. Pilots must compensate by manually setting the power or taking other actions.

If the autothrottle failure proves central to the probe, it’s likely to put the focus on pilot actions and training as well.