Lion Air Crash: Aircraft Should Have Been Grounded

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"In our view, the plane was not airworthy" during its previous flight, said Nurcahyo Utomo, head of Indonesia's national transport safety committee (KNKT), in a press conference today in Jakarta. He also expressed concern that the plane had not been repaired after those flights.

Data from the jetliner crashed in the Java Sea in October showed that the pilots fought with the equipment nearly since the moment Boeing 737 took off as its nose was repeatedly forced down by the malfunctioning sensors.

"It's all consistent with the hypothesis of this problem with the M.C.A.S. system", said R. John Hansman Jr., a professor of aeronautics and astronautics and director of the worldwide centre for air transportation at the Massachusetts Institute of Technology.

"We still don't know yet, if it contributed or not", he said in response to a question.

"The plane was airworthy", he added.

Indonesian authorities are expected to release their preliminary findings later on Wednesday, although it is unclear whether they will offer a probable cause for the crash.

The investigation into the crash is in its early stages and is hampered by the lack of evidence from the cockpit voice recorder, which remains lost on the seabed.

The air flight maintenance log showed six problems had been identified on the plane since 26 October, including errors with its airspeed and altitude information displays.

New details of Flight JT610's final moments were also included in the report. Pilots reportedly made over two dozen attempts to regain control of the plummeting aircraft, but failed, losing radio contact and crashing just 13 minutes after taking off from the capital city of Jakarta.

Eleven minutes into the flight, the captain told air traffic control that the jet's altitude could not be determined as instruments were giving different readings.

Seconds later, the flight data recorder - which was retrieved from the sea bed days after the crash - stopped recording. An automated Boeing anti-stall system pushed the nose down, while pilots tried to use their controls to bring it back up.

Each time the flawed system directed the plane downwards, the pilots had to struggle, manually pushing the nose back up again.

Pilots flying the same plane a day earlier had experienced a similar problem until they used switches to shut off the system, KNKT said in its statement today.

In a preliminary report on the accident, Indonesia's National Transportation Safety Committee said the aircraft was unairworthy and should have been grounded.

The pilots of that flight reported problems to Lion Air's maintenance team, which checked the jet and cleared it for takeoff on the doomed flight JT-610 the next morning.

Despite a dubious safety record and an avalanche of complaints over shoddy service, the budget carrier's parent Lion Air Group, which also operates Batik Air and Wings Air, has captured half the domestic market in less than 20 years of operation to become Southeast Asia's biggest airline.

The preliminary report does not fully unravel the mystery behind the crash.

Coming from an aviation family, she said that Suneja's sister wanted to follow in his footsteps, but that the fatal accident had shaken her faith in the technology.

"This is a report of facts", said Mr Nurcahyo.

KNKT plans, among other things, to conduct aircraft simulator exercises in the Boeing engineering simulator in the United States.

The doomed plane's flight data recorder showed that pilots had repeatedly tried to correct its nose from pointing down, possibly after erroneous data from AoA sensors was fed into a system that automatically adjusts some of its movements.