CHICAGO (Reuters) – Boeing Co said on Sunday that a Safety Review Board convened in late 2018 corroborated its prior conclusion that the angle-of-attack (AOA) Disagree alert on the 737 MAX, which has suffered two fatal crashes, was not necessary for the safe operation of commercial aircraft.

The statement follows a series of negative news reports and a recent decision by Boeing to make the AOA Disagree alert a standard, standalone feature on the 737 MAX before the grounded jets returns to service.

The AOA sensor, which was previously an optional item on the MAX and the previous NG model of the 737 narrowbody series, is one of several ways of measuring the state of the aircraft.

When the MAX returns to service, all MAX production aircraft will have an activated and operable AOA Disagree alert and an optional angle of attack indicator, Boeing reiterated on Sunday.

Customers with previously delivered MAX airplanes can activate the sensor.