You may have heard that a Lion Air flight crashed off the coast of Indonesia last week, killing some 189 people. Investigators have been working to ascertain the cause of the crash. The aircraft was a Boeing 737 Max, the latest iteration of one of the company’s most popular and widely used jets. Boeing today issued a safety warning to pilots that inaccurate readings from an onboard flight monitoring system can cause this particular plane to “abruptly dive.”
Boeing mentions in its safety message to pilots that investigators have found that one of the angle of attack sensors on the plane had provided incorrect readings. It’s a calculation of the angle at which the wind is passing over the airplane’s wings. Pilots can lose control of an aircraft if there’s an angle of attack error and it can often be impossible to regain control.
The systems rely on data from the sensors to ascertain if the plane’s nose is too high relative to the current of air because that can lead to an aerodynamic stall. Boeing 737 Max jets will automatically try to push down the nose if they detect that an aerodynamic stall is possible even if the pilots are manually flying the plane.
There are procedures in place that pilots can follow if the sensors are sending incorrect data but it’s unclear whether the pilots of that ill-fated flight had enough time to apply those procedures as the plane crashed shortly after takeoff.
Boeing has now asked pilots to follow those existing “flight crew procedures” if the data coming from the sensors on their 737 Max is not correct. The safety message applies to all 200 Boeing 737 Max plans that are in service across the globe. Boeing has orders for 4,500 additional 737 Max jets.