WASHINGTON: The Lion Air pilots whose plane nosedived into the sea in October, killing all those aboard, were battling multiple malfunctions during the short, doomed flight, according to a trove of new data released by Indonesian investigators.
They faced a cacophony of warnings that started seconds after takeoff and continued for the remaining 11 minutes before the crash.
The alerts included a so-called stick shaker — a loud device that makes a thumping noise and vibrates the control column to warn pilots they’re in danger of losing lift on the wings — and instruments that registered different readings for the captain and copilot, according to data presented to a panel of lawmakers in Jakarta Thursday.
It also showed for the first time that in the final seconds, as they struggled to pull the Boeing Co. 737 Max 8 out of a dive that was being commanded by the plane’s flight computers, the control column was resisting them, requiring a force of as much as about 100 pounds of pressure.
However, the data also show that the plane was controllable — the pilots had done so for about 10 minutes before the final plunge — and records from the previous flight of the same jet showed another set of pilots had an identical set of failures and landed without incident.
“There are so many questions it’s sort of hard to put in one short statement,” said Roger Cox, a retired investigator with the US National Transportation Safety Board and a former airline pilot.
“I would be very interested in knowing why one crew as able to cope with this stick shaker and trim anomaly, and why the next crew could not,” Cox said. “And I’d want to know why Lion Air could not or would not repair the problem.”
Lion Air Flight 610 crashed into the Java Sea on Oct 29, killing all 189 people on board. The jet was knifing through the air at about 500 miles (805 kilometres) an hour, or more, in its final seconds as it neared the water, according to the plane’s crash-proof flight recorder.
In a statement, Boeing deferred comment to the Indonesian National Transportation Safety Committee. The manufacturer has sent two updates to operators of the Max jet since the accident, which include reminders that there are existing emergency procedures for such situations.
Preliminary findings may be released on Nov 28, Soerjanto Tjahjono, the committee’s chairman, told lawmakers in Jakarta on Thursday.
In the past week, Boeing has stepped up its response by pushing back on suggestions that the company could have better alerted its customers to the jet’s new anti-stall feature. The three largest US pilot unions and Lion Air’s Operations Director Zwingly Silalahi have expressed concern over what they said was a lack of information.