Hong Kong authorities have warned Boeing 787 operators of possible adverse autopilot behaviour during localiser capture at the city’s international airport, after the latest in a string of incidents involving the type.

A newly-issued NOTAM instructs carriers to check a Boeing flight crew operations bulletin referring to “anomalies” in localiser capture and possible misbehavior by the autopilot flight-director system, particularly during ILS approaches to runways 25R and 25L.

It states that the issue can lead to “proximity to high grounds”, adding that – if it doubt – crews should climb back to minimum sector altitude and conduct a missed approach.

The NOTAM follows an incident on 21 April involving an Air Canada 787-9, arriving from Vancouver, which had been cleared for an ILS approach to 25L.

Transportation Safety Board of Canada says the crew contacted air traffic control after reaching the waypoint LOTUS, located about 15nm from the threshold, and reported being established on the ILS.

After controllers advised the crew to switch to the Hong Kong tower frequency, they observed the aircraft “overshooting the localiser” of 25L and descending to 3,900ft – below the minimum sector altitude of 4,300ft.

Controllers contacted the crew to warn of terrain and the pilots corrected the flightpath to re-intercept the ILS. The crew reported receiving a “false capture” of the ILS, says the safety board, which adds that the pilots had visual contact with both the terrain and the airport at the time.

The safety board indicates that only four occupants were on board the 787 (C-FNOH), suggesting it was operating a special freight supply service.

Boeing has been working on a resolution to the issue, which has affected several 787 flights into Hong Kong including four between July and October last year involving aircraft operated by Virgin Atlantic, Ethiopian Airlines, and Etihad Airways.