B777 crew had FMC data dropout for the departure SID at sea.

Attributes
ACN	504141
Time
Date	200103
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : sea.airport
State Reference	WA
Altitude	msl single value : 400
Environment
Light	Daylight
Aircraft 1
Controlling Facilities	tower : sea.tower
Operator	common carrier : air carrier
Make Model Name	B777 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	other other
Flight Phase	climbout : initial
Route In Use	departure sid : bangr 2
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	504141
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
ASRS Report	504142
Events
Anomaly	aircraft equipment problem : critical non adherence : published procedure non adherence : clearance other anomaly other other spatial deviation
Independent Detector	other controllera other controllerb other flight crewa other flight crewb
Resolutory Action	controller : issued alert controller : issued new clearance flight crew : became reoriented flight crew : returned to intended or assigned course other
Consequence	other other
Supplementary
Problem Areas	Aircraft FAA
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

FMC data dump. After several attempts to uplink flight plan at sea gate, flight plan would not uplink. FMC buffer was clear manually loaded flight plan and all other data including bangr 2 SID. Once gate was clear normal uplink function occurred. On departure from runway 16L bangr 2 SID dumped from FMC. LNAV was active. Relief pilot was flying started flight director command for right turn. Captain told relief pilot to turn back to the left and follow SID and the tower questioned if we were flying bangr 2 departure. Frequency change to departure 120.4. Controller asked if we were on bangr 2. We asked for vectors to assigned route until FMC problem could be corrected. Inserted bangr and asked for direct bangr. Rechked route. All other data remained normal. Continued to nrt with no other problems.

Original NASA ASRS Text

Title: B777 CREW HAD FMC DATA DROPOUT FOR THE DEP SID AT SEA.

Narrative: FMC DATA DUMP. AFTER SEVERAL ATTEMPTS TO UPLINK FLT PLAN AT SEA GATE, FLT PLAN WOULD NOT UPLINK. FMC BUFFER WAS CLR MANUALLY LOADED FLT PLAN AND ALL OTHER DATA INCLUDING BANGR 2 SID. ONCE GATE WAS CLR NORMAL UPLINK FUNCTION OCCURRED. ON DEP FROM RWY 16L BANGR 2 SID DUMPED FROM FMC. LNAV WAS ACTIVE. RELIEF PLT WAS FLYING STARTED FLT DIRECTOR COMMAND FOR R TURN. CAPT TOLD RELIEF PLT TO TURN BACK TO THE L AND FOLLOW SID AND THE TWR QUESTIONED IF WE WERE FLYING BANGR 2 DEP. FREQ CHANGE TO DEP 120.4. CTLR ASKED IF WE WERE ON BANGR 2. WE ASKED FOR VECTORS TO ASSIGNED RTE UNTIL FMC PROB COULD BE CORRECTED. INSERTED BANGR AND ASKED FOR DIRECT BANGR. RECHKED RTE. ALL OTHER DATA REMAINED NORMAL. CONTINUED TO NRT WITH NO OTHER PROBS.

Data retrieved from NASA's ASRS site as of July 2007 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.