**Update: 03/05/20 @ 18:00 UTC – Official statement from Boeing included.**
Over the past year, there have been five incidents at Hong Kong International Airport (HKIA) involving Boeing 787 aircraft descending below safe minimum altitude. These occurrences took place after the aircraft failed to capture the localizer during landing, resulting in aircraft action unexpected by air traffic control. Recently, Hong Kong’s Civil Aviation Department informed Simple Flying that Boeing will introduce a software fix for this recurring issue.
A basic background
For the non-pilots out there, during normal arrivals, aircraft will “capture” and follow the localizer signal (a radio signal) of the instrument landing system (ILS) at the airport. Upon doing so, it assists pilots in aligning with the extended centreline of the arrival runway. This system and the signals it uses can be used to autoland an aircraft under the right conditions.
However, aircraft may sometimes fail to capture the localizer signal on their approach or end up capturing a false signal. This can lead to the aircraft reacting in ways that are unexpected by air traffic control.
In the case of aircraft arriving at Hong Kong International, the airport’s surrounding terrain is believed to play a part in these false or failed signal captures. Furthermore, Hong Kong Aeronautical Information Services’ (AIS) believes that interference is coming from aircraft taxiing in the vicinity, as stated on their website:
10.6 Pilots are warned that during ILS CAT I operations RWY 07R and RWY 25L GP signals may be liable to interference from aircraft taxiing in the vicinity of the GP aerial. Pilots should therefore closely monitor their ILS approach profile and rate of descent.
HKIA and the 787
The Hong Kong Civil Aviation Department (HKCAD) tells Simple Flying that a bulletin has been issued by Boeing, showing that aircraft operators reported “failure to properly capture the localizer.” As such, Boeing believes it has determined the root cause and will introduce a software fix to the 787 to “rectify the localizer capture anomaly.”
The HKCAD adds that since the failure can take place at any airport, a bulletin has gone out with operating instructions to 787 flight crews for handling such situations before completing the software fix.
Boeing responded to our inquiry by saying:
“Boeing is working closely on this issue with the AAIA and CAD in Hong Kong as well as the FAA. Boeing has provided information to 787 operators, including instructions for pilots to monitor data closely on certain approaches. Boeing is also working on a permanent resolution.”
Simple Flying reached out to Boeing to get more details on the software fix. However, due to the publishing time and date of this article, the company was unable to respond before the time of release. Of course, we will update this article should a response be received.
Hopefully, once released and installed, this software fix will mean that we see fewer false-captures at HKIA leading to aircraft descending below the safe minimum altitude. With many aircraft grounded around the world at this time, it may be the optimum period for Boeing to get this update out to its customers.
If you’ve been following this story with us, let us know your thoughts on this most recent development! Will Boeing’s update finally end these incidents at HKIA? Let us know in the comments.