Boeing 787 operators are being instructed to check flight-management system software to eradicate a glitch which could lead to uncommanded manoeuvres.
The directive has been spurred by an incident in which a 787 entered an uncommanded descent and turn after a change, during flight, to the spare flight-management function.
Investigation of the incident traced it to retention of “stale” flight data in this function, says the US FAA.
The directive, effective 22 March, orders inspection of the flight-management system within 12 months to check for installation of certain operational software and, if necessary, follow-up software work.
It says the glitch, if not corrected, could potentially put the aircraft on an unintended course towards terrain or place it at risk of mid-air collision.
Boeing has indicated support for the directive, which was originally proposed in October last year.