Boeing has issued a safety warning for airlines using the 737 MAX. The
warning relates to what pilots have to do in case a certain sensor does not
function properly. The reason for the warning is the crash with a Boeing
737 MAX 8 from Lion Air, last week in the Java Sea.
 
The safety warning is published in an Operations Manual Bulletin, which the
aircraft manufacturer sends to customers. Normally the American aviation
authority FAA follows this with a so-called Airworthiness Directive,
whereby users are forced to take action.
 
The warning more specifically concerns a so-called Angle or Attack (AOA)
sensor. The Indonesian Transport Safety Council has established that
onboard flight JT610 there was incorrect input from one of those AOA
sensors. The Angle or Attack is the angle of the wings with respect to the
airflow.
 
In the service bulletin, users of the 737 MAX are called upon to point out
the circumstances in which an AOA sensor does not work properly in existing
flight crew procedures.
 
Boeing says in a statement to offer every possible support in the
investigation into the cause of the accident. The Indonesian authorities
are in charge of the investigation.

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