Lion Air 737 Max plane pilots 'scoured handbook' before crash

But there was a third person in the cockpit, deadheading pilot, who correctly identified the problem and advised crew on how to disable a malfunctioning flight-control system, Bloomberg reports quoting two sources familiar with the investigation.

Investigators said the jet experienced problems on its last four flights - including, crucially, the flight that crashed, according to Tjahjono.

The pilots of the doomed Lion Air flight that crashed into the Java Sea last October frantically searched the aircraft's manual to try to find a way to keep the plane under control before the crash, cockpit voice recordings show. The presence of a third pilot in the cockpit wasn't contained in Indonesia's National Transportation Safety Committee's November 28 report on the crash and hasn't previously been reported. Investigators have released preliminary data obtained from the flight data recorder of the Ethiopian Airlines aircraft.

Muilenburg said a software upgrade for the 737 MAX aircraft that the planemaker started in the wake of October's deadly Lion Air crash in Indonesia was coming "soon".

A report by Indonesia's National Transportation Safety Committee (NTSC) had mentioned that the plane experienced multiple failures previously, which were not fixed.

Boeing Co declined to comment on Wednesday because the investigation was ongoing. Boeing shares were unchanged at $374.57 in pre-market trading Wednesday in NY.

The initial investigation points to a fault in the MCAS system. The pilot knew how to override the automated system.

The Boeing 737 MAX 8 has come under further scrutiny after an Ethiopian Airlines flight crashed on March 10, 2019 and killed all 157 people on board.

The MAX, which offers cost savings of about 15 per cent on fuel, was developed for service from 2017 after the successful launch by its main rival of the Airbus A320neo.

On Tuesday the Department of Transportation requested an audit of the FAA's certification process of the Boeing 737 MAX.

It noted it was unusual for federal prosecutors to investigate details of regulatory approval or to use a "criminal probe" to delve into dealings between the FAA and Boeing.

One company, Norwegian Airlines, has already said it will seek compensation after grounding its MAX aircraft.

"We have been working very hard to minimize that impact", said Lucie Guillemette, the airline's executive vice president. "It makes us question, 'Is that everything, guys?' I would hope there are no more surprises out there". Among major U.S. air carriers (IYT), Boeing has received orders for 280 jets from Southwest Airlines (LUV) and 100 plane orders each from United Airlines (UAL) and American Airlines (AAL).

Boeing (BA) announced management changes in its commercial airplane unit.

"It's simply implausible that this MCAS deficiency by itself can down a modern jetliner with a trained crew", Guzzetti said.

On the Lion Air flights, the angle-of-attack sensor had failed and was sending erroneous readings indicating the plane's nose was pointed dangerously upward.

  • Tracy Klein