Lion Air crash: Jet had airspeed problems on final four flights

Minnie Murray
November 8, 2018

Indonesia's National Transportation Safety Committee (NTSC) said it had agreed with Boeing on procedures that the airplane manufacturer should distribute globally on how flight crews can deal with "angle of attack" sensor problems following the October 29 crash that killed all 189 people on board.

Lion Air Flight 610 crashed into the Java Sea with both engines running, meaning the airliner didn't explode in mid-air as previously thought, investigators said Monday. The bulletin, which will be released as early as Wednesday morning Jakarta time, will alert pilots to follow an existing procedure to handle the problem, the person said.

Under some circumstances, a 737 MAX jet could automatically push down its nose if it detects that a stall is possible, based on the angle of attack.

Lion Air confirmed to CNN that the same aircraft was used on that route, and Indonesian authorities confirmed that the pilot on the flight reported a problem with one of the plane's instruments.

However, this new reminder from Boeing raises questions about the pilots' actions, how the flight crews are trained and if the maintenance that was performed was adequate.

USA aviation regulators said they are drafting an order requiring that airlines follow Boeing's instructions.

However, it's unclear whether the warning is being issued because investigators have conclusively determined that a flight-monitoring system error was the cause of the crash.

Authorities have yet to recover the jet's cockpit voice recorder from the sea floor, just northeast of Jakarta, where the plane crashed 13 minutes after taking off from the Indonesian capital.

"When there was a problem, the pilot would write it down and the mechanic would do (a repair).Then the plane would be declared airworthy".

The problem with the planes is in the "angle of attack" sensor which calculates the position of the plane relative to the air current. The committee said they were dealing with an erroneous airspeed indication.

Experts have been puzzled about what could have caused the jet to go down in clear skies, unlike other major airplane disasters in which weather or older jets were major factors.

The jet reported a discrepancy in its angle of attack sensor during a flight from Bali to Jakarta the day before it crashed.

While search teams scouring the waters managed to bring up the flight data recorder, a separate recorder that captures cockpit conversations and background noise is still buried in the seabed where the plane plunged.

"If you were driving down the interstate and the speedometer failed, would you expect to crash the auto?" said John Cox, a former airline pilot and now a safety consultant.

The nation's rescue agency, scouring the sea for victims' remains, said Wednesday that it will extend the search by three more days.

A DJPU statement said the audit will include a review of Lion Air's operating procedures, flight crew qualifications, and institutional cooperation. The head of Indonesia's National Transportation Safety Committee, Soerjanto Tjahjono, told reporters in Jakarta on Monday that he was discussing the options for wider inspections with Boeing and his us counterparts.

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