The pilots of the fatal Lion Air Boeing 737 MAX searched pilot handbooks and checklists trying to work out why their jet was pitching nose down and one prayed as the aircraft dived into the ocean killing all 189 aboard, according to sources that have heard the cockpit voice recorder.
The report carried by Reuters says that the problem with the angle of attack sensor started just after take-off when the first officer reported a “flight control problem” to air traffic control.
While the first officer did not specify the problem, the source said airspeed was mentioned on the cockpit voice recording, and an indicator showed a problem (Angle of Attack sensor) on the captain’s display but not the first officer’s.
SEE: Boeing’s 737 MAX statement
READ: Pilot Training, Automation under intense scrutiny
The captain then asked the first officer to check the quick reference handbook, which contains checklists for abnormal events.
For the next nine minutes, the Lion Air 737’s warning system alerted the pilots it was approaching an aerodynamic stall and pushed the nose down in response.
Sources said that the captain fought to climb, but the computer, still incorrectly sensing a stall, continued to push the nose down using the plane’s trim system located in the tail of the aircraft.
But the sources told Reuters that the Lion Air pilots “didn’t seem to know the trim was moving down, they thought only about airspeed and altitude. That was the only thing they talked about.”
This activated the stabilizer trim wheel in the cockpit which would have been spinning forward and making a loud noise. How the pilots could have missed this or its significance has stunned 737 pilots.
What is called a “Runaway Stabilizer Trim” is a memory item for pilots. You don’t need the checklist, you simply switch it off.
According to the sources the pilots of JT610 remained calm for most of the flight and near the end, the captain requested the first officer to fly while he checked the manual for a solution but he was unable to control the plane with the Flight Data Recorder revealing his inputs were weaker than the captain.
In the last minute, the Indian-born captain was silent while the Indonesian first officer said “Allahu Akbar,” or “God is greatest.”
Lion Air and Boeing did not comment on the report.
The Indonesian investigation agency KNKT, said last week that the final report would not be issued till July or August.
The Reuters report comes after Bloomberg, this time quoting two sources, reported that a pilot traveling in the jump seat of a flight on the same plane the night before diagnosed a similar problem with the aircraft and told the flight crew how to fix it.
Bloomberg reported the third pilot told the crew to hit two switches that turned off the stabilizer trim.
