Incident Overview
On 20 July 2014, a Boeing 787-800 was descending for landing at Warsaw Chopin Airport (EPWA). As the aircraft neared the BIMPA point, air traffic control changed the approach direction from runway 15 to runway 33. During the crew's attempt to update the Standard Terminal Arrival Route (STAR) from BIMPA 3P to BIMPA 4U, the Flight Management System (FMS) lost position indication.
The crew requested vectoring from ATC to align with runway 33 and subsequently executed a visual approach and landing. The report notes that there is no information from the crew regarding whether the FMS position indication was restored after landing.
Background and Investigation
The investigation was supervised by Piotr Lipiec. The operator conducted interviews with B787 fleet pilots during pre-flight briefings and learned that similar events had occurred previously, but indications were quickly restored, leading to a lack of Air Safety Reports (ASR).
Manufacturer Honeywell, which developed the B787 software, was able to replicate the reported problem. The investigation determined that the issue occurs only during STAR procedures with exactly 14 waypoints and when attempting to select a different approach not contained within that procedure. A solution was proposed in the Flight Management Function (FMF) BP3 modification, available in the fourth quarter of 2015.
In the interim, Honeywell investigated other possibilities, such as a workaround via modification of the NAV DB. The aircraft manufacturer planned to communicate a new NAV DB version containing the fix.
Remedial Actions
Since Boeing proposed a solution in the third quarter of 2015, the operator negotiated with the manufacturer to accelerate the fix, but without results.
On 23 December 2015, Service Bulletin B787-81205-SB340013-00 issue 01 was released, followed by revision 02 on 6 May 2016. These modifications, known as Block Point 3 (BP3), included software updates to the Flight Management System (FMS), Thrust Management System (TMS), and Communication Management Function (CMF). The operator informed the commission of its efforts to implement these modifications.
Cause
The cause of the aviation incident was limitations in the software of the B787 aircraft's onboard systems.
Safety Actions Taken by the Investigating Entity
1. The Fleet Safety Pilot analyzed the event and described it in the fleet safety bulletin for July. 2. The operator’s OTE department contacted the aircraft manufacturer to explain the cause of the fault and how to eliminate it. 3. The operator informed the commission of work to implement the modifications mentioned above.
The commission did not formulate any safety recommendations.