FAA issues warning over Dreamliner autopilot fault

The US Federal Aviation Administration has issued a Special Airworthiness Information Bulletin (SAIB) for owners and operators of the Boeing 787, warning of a possible failure in the aircraft’s autopilot system when utilised on landing.

The SAIB, which is a non-regulatory notice used by the FAA to provide operators with vital information and guidance on aircraft, covered all models of the Dreamliner – 787-8, -9 and -10. 

It served to encourage owners and operators of the 787 Dreamliner to ensure pilots and cabin crew are fully aware of the issue with the aircraft’s autopilot system on ILS landing.

Specifically, the SAIB noted that the autopilot flight director system was “not providing proper guidance to capture the localiser when intercepting the localiser at large angles (40 degrees or more) from the runway and beam centerline”.

The fault was essentially causing the aircraft to deviate from the runway centerline, and descent on the wrong heading.

The SAIB noted that Boeing is “currently developing” an update to its autopilot flight director system to correct the “erroneous localiser mode behaviour during ILS approaches”.

This comes after a number of incidents involving Boeing 787 ILS approaches in Hong Kong, in which Dreamliners descended below the specified safe minimum altitude.

It was believed at the time that the terrain around the airport was resulting in the false or railed localiser signal captures.

At the time, Boeing said it was “working closely on this issue” with authorities, and had also released information to operators to encourage pilots to closely monitor data on certain approaches.

The latest SAIB issuance follows a slew of quality control issues for the 787, which has now seen at least four manufacturing faults brought to light within the last month alone.

This includes two issues in the fuselage of the aircraft, one in its horizontal stabiliser, and most recently, an issue present on its vertical tail fin.

Manufacturing issues have now been linked to two Boeing Dreamliner plants, one in Salt Lake, Utah, and the other in Charleston, South Carolina.

Only eight 787s have been grounded over safety concerns to date, however hundreds are currently at risk as the FAA continues its probe into these flaws.