Lion Air report

Before the flight

● Sensors that measure speed were flushed and checked, and an electrical plug was cleaned before the fatal flight.

● Mechanics did not check a sensor that measures whether the nose of the plane is pointing up or down.

During the flight

● That “angle of attack” sensor gave faulty readings throughout the 11-minute flight.

● It triggered a system that automatically pointed the plane’s nose down 26 times.

● The pilots responded by manually fighting to correct the pitch.

● Pilots even asked air traffic controllers to tell them how fast and high they were flying.

● Searchers have not yet recovered the plane’s cockpit voice recorder, which could tell investigators what the pilots were doing — or failing to do — to regain control of the plane.

What the manufacturer says

● US-based Boeing declared that the Boeing 737 MAX 8, its newest plane, is safe.

● Boeing noted that the crew of the plane’s previous flight a day earlier had responded correctly to the automatic nose-down pitch and flew the plane manually.

● They also ran safety checklists.

● The preliminary report does not say whether pilots on the deadly flight took those steps, Boeing said.

● Boeing has said that the procedure to correct an automatic nose-down pitch is in the operating manual and pilots should have known about it.

Recommendations

● The report by Indonesia’s safety commission repeated earlier recommendations made just after the disaster that pilots be better versed in emergency procedures and aware of past aircraft problems.

● Lion Air should ensure that pilots follow proper procedures “to improve the safety culture”.

Expert’s view

● Peter Lemme, an expert in aviation and satellite communications and a former Boeing engineer, compared the scene in the cockpit to “a deadly game of tag”.

● Pilots failed to follow the known procedure for countering incorrect activation of the automated safety system.

● Lemme said he was troubled that there weren’t easy checks to see if sensor information was correct, that the crew of the fatal flight apparently wasn’t warned about the problems on previous flights and that the Lion Air jet wasn’t fully repaired after those flights.