Narrative:

In cruise flight; under radar contact; montreal center cleared MD11 direct waypoint (mt) then fpr. PF (first officer) selected the 'direct-to' tile on mcdu and the 'lsk 1L' next to (mt). He visually confirmed navigation in roll FMA and (mt) as active waypoint on navigation display. Approximately 30 seconds later; after selecting the 'progress' tile on the mcdu; the PF noticed (mt) was the 'from' waypoint on the mcdu; but the navigation display still displayed (mt) as the active waypoint. He re-accomplished the 'direct-to' by typing (mt) into the 'direct-to' block and received the correct indications on both the navigation display and the mcdu. PF and pilot monitoring discussed the anomaly; confirming what they had seen and that all indications appeared correct now. Approximately 30 mins later; with pilot monitoring (now the captain) and PF (now the relief pilot); aircraft sequenced (mt) and initiated a slight left turn to join J551 to yvo per fpr. Pilot monitoring noticed aircraft start the left turn and confirmed navigation in roll FMA and yvo as active waypoint on the navigation display. Approximately 15 mins later; montreal asked where we were going. Pilot monitoring noted/confirmed navigation in roll FMA and yvo as active waypoint on navigation display. However; we had no magenta line from aircraft symbol to yvo which was located at 10 O'clock position and 90 NM on the navigation display. Montreal told us we were off course then cleared us to a fix down track. They also stated they would report the incident. After our crew debrief; 2 lessons learned are apparent: 1) although we were in radar contact; greater diligence after sequencing (mt) would probably have enabled the crew to detect the anomaly and prevent the navigation error. We did confirm navigation and the correct active waypoint on the navigation display but failed to catch the subsequent FMS automatic sequence to a down track waypoint. 2) while the PF/pilot monitoring observed good CRM in their status brief to the pilot returning from a rest cycle; they overlooked briefing the previous FMS anomaly. Had they briefed this problem we might have caught the subsequent anomaly and prevented the navigation deviation. Also of note; but possibly unrelated; the aircraft experienced a lightning strike on the leg prior to ours.

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Original NASA ASRS Text

Title: MD11 FLT CREW EXPERIENCES NAV DEVIATION FOLLOWING FMS ANOMALY.

Narrative: IN CRUISE FLT; UNDER RADAR CONTACT; MONTREAL CTR CLRED MD11 DIRECT WAYPOINT (MT) THEN FPR. PF (FO) SELECTED THE 'DIRECT-TO' TILE ON MCDU AND THE 'LSK 1L' NEXT TO (MT). HE VISUALLY CONFIRMED NAV IN ROLL FMA AND (MT) AS ACTIVE WAYPOINT ON NAV DISPLAY. APPROX 30 SECONDS LATER; AFTER SELECTING THE 'PROGRESS' TILE ON THE MCDU; THE PF NOTICED (MT) WAS THE 'FROM' WAYPOINT ON THE MCDU; BUT THE NAV DISPLAY STILL DISPLAYED (MT) AS THE ACTIVE WAYPOINT. HE RE-ACCOMPLISHED THE 'DIRECT-TO' BY TYPING (MT) INTO THE 'DIRECT-TO' BLOCK AND RECEIVED THE CORRECT INDICATIONS ON BOTH THE NAV DISPLAY AND THE MCDU. PF AND PLT MONITORING DISCUSSED THE ANOMALY; CONFIRMING WHAT THEY HAD SEEN AND THAT ALL INDICATIONS APPEARED CORRECT NOW. APPROX 30 MINS LATER; WITH PLT MONITORING (NOW THE CAPT) AND PF (NOW THE RELIEF PLT); ACFT SEQUENCED (MT) AND INITIATED A SLIGHT L TURN TO JOIN J551 TO YVO PER FPR. PLT MONITORING NOTICED ACFT START THE L TURN AND CONFIRMED NAV IN ROLL FMA AND YVO AS ACTIVE WAYPOINT ON THE NAV DISPLAY. APPROX 15 MINS LATER; MONTREAL ASKED WHERE WE WERE GOING. PLT MONITORING NOTED/CONFIRMED NAV IN ROLL FMA AND YVO AS ACTIVE WAYPOINT ON NAV DISPLAY. HOWEVER; WE HAD NO MAGENTA LINE FROM ACFT SYMBOL TO YVO WHICH WAS LOCATED AT 10 O'CLOCK POS AND 90 NM ON THE NAV DISPLAY. MONTREAL TOLD US WE WERE OFF COURSE THEN CLRED US TO A FIX DOWN TRACK. THEY ALSO STATED THEY WOULD RPT THE INCIDENT. AFTER OUR CREW DEBRIEF; 2 LESSONS LEARNED ARE APPARENT: 1) ALTHOUGH WE WERE IN RADAR CONTACT; GREATER DILIGENCE AFTER SEQUENCING (MT) WOULD PROBABLY HAVE ENABLED THE CREW TO DETECT THE ANOMALY AND PREVENT THE NAV ERROR. WE DID CONFIRM NAV AND THE CORRECT ACTIVE WAYPOINT ON THE NAV DISPLAY BUT FAILED TO CATCH THE SUBSEQUENT FMS AUTO SEQUENCE TO A DOWN TRACK WAYPOINT. 2) WHILE THE PF/PLT MONITORING OBSERVED GOOD CRM IN THEIR STATUS BRIEF TO THE PLT RETURNING FROM A REST CYCLE; THEY OVERLOOKED BRIEFING THE PREVIOUS FMS ANOMALY. HAD THEY BRIEFED THIS PROB WE MIGHT HAVE CAUGHT THE SUBSEQUENT ANOMALY AND PREVENTED THE NAV DEV. ALSO OF NOTE; BUT POSSIBLY UNRELATED; THE ACFT EXPERIENCED A LIGHTNING STRIKE ON THE LEG PRIOR TO OURS.

Data retrieved from NASA's ASRS site as of May 2009 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.