Boeing Set to Issue Safety Warning for 737 MAX, Aircraft Involved in Lion Air Crash

Just over one week after Lion Air Flight 610, a Boeing 737 MAX aircraft, crashed off the coast of Indonesia, Boeing is expected to send a bulletin to operators of the aircraft that incorrect readings from its flight-monitoring system can cause the planes to aggressively dive, a person familiar with the matter told Bloomberg.

The warning that Boeing is reportedly gearing up to send to 737 MAX operators comes after preliminary findings from last week's crash, said the person quoted by Bloomberg, who asked to remain anonymous as details are still confidential. The warning is expected to alert pilots to follow an existing procedure in case an issue arises. This warning could be released as early as Wednesday morning Jakarta time.

More specifically, the bulletin is expected to say that under certain circumstances, the aircraft will automatically push the nose of the plane downward if its angle-of-attack sensor detects that a stall is possible. The angle of attack is the angle at which air passes over the wings, and a stall is what happens when the flow of air over the wings is not enough to generate sufficient lift to keep an airplane flying. Pushing the nose down increases the airspeed, or the speed of the plane relative to the surrounding air, which produces more lift.

It's not yet clear at this point if the findings in the 737 MAX bulletin, expected to be announced by Boeing, explain what caused the Lion Air crash last week, which killed all 189 people on board. However, just before the aircraft — a Boeing 737 MAX 8 (brand new, with registration PK-LQP) — lost contact with air traffic control, the pilots requested to return to Jakarta about 12 miles after takeoff because of an erroneous airspeed indication. That same aircraft had inaccurate airspeed readings for days before its final flight.

Boeing could not be immediately reached for comment.

While many details of the bulletin remain unknown, it represents a major step for Boeing and its operators. In the US, several airlines operate Boeing 737 MAX aircraft of different variants. These include American Airlines, Southwest Airlines and United Airlines. Alaska Airlines also has an order for 32 737 MAX 9s, which have yet to be delivered. Worldwide, the MAX — the latest evolution of the workhorse 737, featuring new engines — is in service with many other carriers, after being introduced in 2017.