<< >> NASA ASRS Report 1478365, September 2017

B787 flight crew reported an anomaly with the navigation function of the FMC during an update of the winds on an oceanic route.

Attributes
ACN	1478365
Time
Date	201709
Local Time Of Day	1801-2400
Place
Locale Reference	CZQX.ARTCC
State Reference	NF
Environment
Light	Night
Aircraft 1
Make Model Name	B787-900
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Route In Use	Oceanic
Flight Plan	IFR
Component
Aircraft Component	FMS/FMC
Person 1
Function	First Officer Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Person 2
Function	Pilot Not Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy

Narrative:

Random route over the atlantic. Using slop (strategic lateral offset procedure); 1 mile right. After midpoint check and before n58w050; I performed a wind update. After wind update was executed; we noticed n58w050 waypoint was white on the navigation display and had dropped from the FMC. Our follow-on waypoint; n60w040 was now the active waypoint. Captain attempted to reload n58w50 as the active waypoint; but the FMC kicked it out. Captain used heading select to stay on track and fly over n58w050. Once reaching n58w050 he selected direct n60w040 and we proceeded on track.there is an [industry] posting referencing FMC anomaly BP3A that boeing has not resolved. This anomaly is very similar to what we experienced. Upon arrival; captain entered anomaly in the logbook. Until this anomaly is corrected by boeing; I suggest not updating winds while on a track or random route over the atlantic.

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Original NASA ASRS Text

Title: B787 flight crew reported an anomaly with the navigation function of the FMC during an update of the winds on an oceanic route.

Narrative: Random route over the Atlantic. Using SLOP (Strategic Lateral Offset Procedure); 1 mile right. After midpoint check and before N58W050; I performed a wind update. After wind update was executed; we noticed N58W050 waypoint was white on the navigation display and had dropped from the FMC. Our follow-on waypoint; N60W040 was now the active waypoint. Captain attempted to reload N58W50 as the active waypoint; but the FMC kicked it out. Captain used heading select to stay on track and fly over N58W050. Once reaching N58W050 he selected direct N60W040 and we proceeded on track.There is an [industry] posting referencing FMC anomaly BP3A that Boeing has not resolved. This anomaly is very similar to what we experienced. Upon arrival; Captain entered anomaly in the logbook. Until this anomaly is corrected by Boeing; I suggest not updating winds while on a track or random route over the Atlantic.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.