B767 FLT CREW EXPERIENCED AUTOPLT DISCONNECT WITH LOSS OF GS ON APCH. GPWS AND TWR TERRAIN WARNINGS WERE ACTIVATED AND AFTER RECOVERY; A VISUAL APCH AND LNDG WERE ACCOMPLISHED. AFDS MALFUNCTIONED ON SUBSEQUENT FLT.

Narrative

AFTER OCEAN XING AT NIGHT; OUR FLT WAS CLRED FOR ILS APCH TO RWY 14 AT LSZH. THE LOC AND GS WERE CAPTURED WITH THE AUTOPLT COUPLED. AT APPROX 6-7 MI ON FINAL; THE AUTOPLT DECOUPLED AND THE GS SIGNAL WAS OBSERVED TO HAVE FAILED. CONCURRENT WITH AUTOPLT DECOUPLING AND GS FAILURE; THE TWR ISSUED A TERRAIN ADVISORY AND THE ACFT TERRAIN WARNING PROVIDED AN ALERT. AS A MISSED APCH WAS COMMENCED; VISUAL CONTACT WITH THE ARPT ENVIRONMENT WAS GAINED; AND A VISUAL LNDG WAS MADE. WE INITIALLY SUSPECTED THE GND-BASED GS SIGNAL HAD FAILED; BUT UPON FURTHER CONVERSATION AFTER FLT WITH THE TWR CTLR BY TELEPHONE; NOW WE SUSPECT ACFT SYS. ADDITIONAL INFO: DID NOT WRITE ISSUE DURING APCH TO LSZH IN MAINT LOG BECAUSE WE SUSPECTED THAT FAILURE OF GS SIGNAL WAS DUE TO GND EQUIP MALFUNCTION. TWR PERSONNEL INDICATED DURING POSTFLT PHONE CALL THAT ILS GND SYS MONITORS INDICATED NO ABNORMALITIES. CALLED CAPT OF OUTBOUND FLT (SAME ACFT) TO RECOMMEND CLOSE SYS MONITORING DURING RETURN FLT. AUTOTHROTTLES TRIPPED OFF TWICE DURING FLT FOR UNKNOWN REASON. HAD SAME ACFT DURING RETURN FROM LSZH. DURING CRUISE; AUTOPLT SELF-DISCONNECTED AND LEFT FMC RESYNCHED. ENTERED THIS IN MAINT LOG. AUTOPLT TRIPPED OFF AGAIN DURING APCH ON RETURN FLT. WE ALSO ENTERED THIS IN MAINT LOG.