FAA cautions airlines 737 MAX crashes initiated by failure of AOA seniors

Federal Aviation Administration (FAA) has cautioned airlines, aircraft-maintenance companies and manufacturers that both crashes of the Boeing 737 MAX were initiated by a faulty reading from a single angle of AOA attack sensor, the administration said.

The Federal Aviation Administration (FAA) said the sensors are vulnerable to damage and must be carefully maintained.

The angle of attack is the angle between an airplane´s wing and the oncoming air flow. If the angle gets too high, above about 14 degrees, the air stream that has been flowing around the contours of the wing will suddenly detach from the wing surface. When this happens, the plane will lose lift and begin to fall — a condition known as stalling.

The sensors are small vanes sticking out from the fuselage that rotate in the air flow.

The FAA typically issues such safety alerts after specific in-flight incidents or reports from airlines of a recurrent problem. In this case, no such reason is given.