TEMPORARY LOSS OF ACFT CTL WHEN A B747-100 FLT HAS AN ENRTE PROB WITH #2 AUTOPLT AND ENDS UP 19 NM N OF COURSE; 1000 FT TOO HIGH. THIS WAS A 6-7 MIN ENCOUNTER WITH AN UNEXPECTED TURN OFF AIRWAY A590 ON FREQ WITH ZOA; CA.

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THIS INCIDENT OCCURRED WITH A B747-100 LEASED TO ACR X ON A MIL CONTRACT FLT BTWN RODN-PANC-KSUU ON THE RODN-PANC SEGMENT; APPROX 13 MINS NE OF PUGAL ON NOPAC AIRWAY 590. THE ACFT WAS OPERATING AT FL330; MACH .848 IN SMOOTH CONDITIONS IN THE CLR WITH A 50 KT TAILWIND (APPROX) AUTOPLT 'B' ENGAGED IN GPS MODE. THE FO WAS PF. THE CAPT WAS AT THE END OF THE PROCESS OF ANNOTATING A PROCEDURAL 10 MIN NAV PLOT. THE ACFT ENTERED (SMOOTHLY) A 15 DEG L TURN (UNCOMMANDED) OFF COURSE AND TRACK WITH A COMMENSURATE RATE OF TURN. THE FO ANNOUNCED THE PROB IMMEDIATELY TO THE CAPT. THE OFF COURSE TURN WAS DISPLAYED IN ALL 3 GPS CDU'S WITH APPROPRIATE COURSE INDICATOR AND TRACK ERROR POINTED DEFLECTIONS. ALL COMPASS/HSI/ROLL INDICATIONS REFLECTED REASONABLE INDICATIONS TO THE ACFT'S TURN. THE AUTOPLT AND ACFT FAILED TO RESPOND TO A 'DIRECT TO ENTRY' IN THE 'FLYING' GPS (#2). THE CAPT SUGGESTED AND SELECTED HDG MODE ON THE AUTOFLT MGMNT MODULE WHEREAS THE BANK NOW RAPIDLY INCREASED TOWARD 35 DEGS OF BANK TOWARDS THE L (AWAY FROM THE HDG BUG) RESULTING IN AN INCREASED RATE OF TURN AND PITCH. THE CAPT ACQUIRED CTL AND DISENGAGED THE AUTOPLT AT APPROX 30 DEGS L BANK AND 9 DEGS NOSE-UP PITCH. THE ACFT WAS ROLLED WINGS LEVEL AND FOUND TO BE CONSIDERABLY OUT OF TRIM; NOSE UP; RESULTING IN AN INITIAL 3000 FPM CLB THAT WAS ARRESTED FINALLY AT FL340-FL341; 1000-1100 FT ABOVE CRUISE FL330. AN IMMEDIATE MANUAL RETURN TO ASSIGNED LEVEL AND TRACK WAS INITIATED BY THE CAPT. ONCE THE ACFT WAS MANUALLY ESTABLISHED BACK ON TRACK AND LEVEL; AUTOPLT 'A' WAS ENGAGED; GPS ODE WAS SELECTED; AND CTL RETURNED TO THE FO. THE FLT CONTINUED TO PANC AND WAS UNEVENTFUL; AND THE FACILITY AUTOPLT'S SYS WAS LOGGED AND A CAPT'S IRREGULARITY RPT WAS FILED. ELAPSED TIME APPROX 6-7 MINS; OFF COURSE 60-70 DEGS N OF TRACK; 19 NM; MAX ALT DEV +1000 FT.