In Indonesia plane crash inquiry, new focus on possible aircraft problems

Investigators on Wednesday broadened the possibilities of what may have contributed to the fatal crash of a Boeing 737 Max 8 last week, suggesting there were aircraft problems that may have played a role in the new plane’s nose-dive into the sea.

Boeing and aviation regulators in the United States, clearly worried that an unforeseen situation may have confronted the cockpit crew, also took steps on Wednesday to strengthen emergency procedures in the operations manual of the new plane, one of the most popular in commercial aviation.

The developments suggested that multiple causes may have combined to create a fatal cascade of problems for Lion Air Flight 610, which plunged into the Java Sea less than 15 minutes after take-off on Oct 29, killing all 189 people aboard.

Haryo Satmiko, the deputy head of Indonesia’s National Transportation Safety Committee, said in an interview that he had held several discussions with Boeing officials after the crash about the possibility that inaccurate readings fed into the Max 8’s computerised system could make the plane enter a sudden, automatic descent.

“This case is something for Boeing to reflect upon,” Haryo said.

Boeing did not comment on Haryo’s assertion. But the company said in a statement on Wednesday that the aircraft’s manual explains how to respond to errant data, and that Boeing had issued a worldwide bulletin about following correct procedures to all operators of the plane on Tuesday.

The Federal Aviation Administration of the United States reinforced the Boeing bulletin on Wednesday by issuing an “Emergency Airworthiness Directive” addressing the possibility of erroneous data from instruments on the plane that could cause it to pitch downward, “making the aircraft difficult to control.”

The directive ordered operators of the Max 8 to ensure that the on-board flight manuals include the procedures on how pilots should handle such a situation.

Boeing’s statement said that it had been told by the Indonesian transportation committee that Flight 610 had “experienced erroneous input” from one of its “angle of attack” sensors. Those instruments, on the nose of the plane, gauge the degree of an aircraft’s ascent or descent and help determine whether the plane might be stalling — meaning it is pointed too high for its current speed.

The Boeing statement said that its bulletin had alerted operators to “existing flight crew procedures” for handling false readings from the Max 8’s angle of attack sensors.

© 2018 New York Times News Service