Narrative:

I was acting as first officer on a scheduled passenger flight operating between hnl-sfo. Aircraft was widebody transport X with dual vlfirst officermegas and FMS. The FMS was inoperative due to a software error. The omegas had been loaded and x-chked in accordance with company operating procedures. On taxi-out to the runway a momentary power interruption occurred for unknown reasons and both omegas went briefly into dead reckoning mode and then returned to normal. During en route climb ZHN cleared us direct to cluts intersection. The captain selected his navigation display to omega and began a left turn to the displayed course. I was busy trying to determine why I could not receive molokai VOR on the #2 navigation receiver and left my display in VOR. The captain questioned the accuracy of his display and asked me to select my display to omega. Both courses indicated 50 degree left of the correct course to cluts. As the aircraft was in the turn, center gave us an immediate right turn to avoid descending traffic Y. The waypoints were crosschecked and confirmed to be correct. When present position direction cluts was reselected, both displays indicated the correct course. This was witnessed by an FAA FSS specialist who was riding jumpseat. This aircraft has a history of unexplained flight director and navigational receiver problems. The problem may have been associated with the power interruption or may have been associated with the power interruption on taxi, but both omegas were checked for accuracy prior to start of takeoff. I was distracted by my VOR receiver problem and the captain was also distracted as he was in the left turn as his flight director displayed a flag and his command bars cleared when my display was selected to omega.

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Original NASA ASRS Text

Title: ACR WDB WITH RNAV EQUIPMENT PROBLEM EXPERIENCES TRACK DEVIATION AND LESS THAN STANDARD SEPARATION ON CLIMB-OUT FROM HNL.

Narrative: I WAS ACTING AS F/O ON A SCHEDULED PAX FLT OPERATING BTWN HNL-SFO. ACFT WAS WDB X WITH DUAL VLF/OMEGAS AND FMS. THE FMS WAS INOP DUE TO A SOFTWARE ERROR. THE OMEGAS HAD BEEN LOADED AND X-CHKED IN ACCORDANCE WITH COMPANY OPERATING PROCS. ON TAXI-OUT TO THE RWY A MOMENTARY PWR INTERRUPTION OCCURRED FOR UNKNOWN REASONS AND BOTH OMEGAS WENT BRIEFLY INTO DEAD RECKONING MODE AND THEN RETURNED TO NORMAL. DURING ENRTE CLB ZHN CLRED US DIRECT TO CLUTS INTXN. THE CAPT SELECTED HIS NAV DISPLAY TO OMEGA AND BEGAN A LEFT TURN TO THE DISPLAYED COURSE. I WAS BUSY TRYING TO DETERMINE WHY I COULD NOT RECEIVE MOLOKAI VOR ON THE #2 NAV RECEIVER AND LEFT MY DISPLAY IN VOR. THE CAPT QUESTIONED THE ACCURACY OF HIS DISPLAY AND ASKED ME TO SELECT MY DISPLAY TO OMEGA. BOTH COURSES INDICATED 50 DEG LEFT OF THE CORRECT COURSE TO CLUTS. AS THE ACFT WAS IN THE TURN, CENTER GAVE US AN IMMEDIATE RIGHT TURN TO AVOID DSNDING TFC Y. THE WAYPOINTS WERE XCHKED AND CONFIRMED TO BE CORRECT. WHEN PRESENT POS DIRECTION CLUTS WAS RESELECTED, BOTH DISPLAYS INDICATED THE CORRECT COURSE. THIS WAS WITNESSED BY AN FAA FSS SPECIALIST WHO WAS RIDING JUMPSEAT. THIS ACFT HAS A HISTORY OF UNEXPLAINED FLT DIRECTOR AND NAVIGATIONAL RECEIVER PROBS. THE PROB MAY HAVE BEEN ASSOCIATED WITH THE PWR INTERRUPTION OR MAY HAVE BEEN ASSOCIATED WITH THE PWR INTERRUPTION ON TAXI, BUT BOTH OMEGAS WERE CHKED FOR ACCURACY PRIOR TO START OF TKOF. I WAS DISTRACTED BY MY VOR RECEIVER PROB AND THE CAPT WAS ALSO DISTRACTED AS HE WAS IN THE LEFT TURN AS HIS FLT DIRECTOR DISPLAYED A FLAG AND HIS COMMAND BARS CLRED WHEN MY DISPLAY WAS SELECTED TO OMEGA.

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.