B747-400
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Communication Breakdown; Troubleshooting
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural MEL / CDL
Flight Crew FLC complied w / Automation / Advisory; Flight Crew Overcame Equipment Problem; General Flight Cancelled / Delayed; General Maintenance Action
MEL; Procedure; Human Factors; Aircraft; Software and Automation
At ZZZ we were notified by the maintenance technician as part of the maintenance briefing that the autoland system was 'still' deferred and that a part was to be installed when the airplane returned in a few days. We noted that the previous crew had performed an autoland to Cat II standards; and had not written up the airplane with an items. An inspection of the logbook showed multiple issues with the First Officer (FO) raw data glideslope (G/S) indication and other failures over the last few landing cycles. During the flight we received messages from dispatch asking us to perform an autoland in ZZZZ1 to recertify the autoland system as that is how the airplane was deferred; i.e. the aircraft could be recertified by a satisfactory autoland being performed. We thought this strange as the previous crew performed an autoland to cat II standards and did not write anything up. The captain needed a landing for currency anyway; so a few messages were exchanged to that effect with dispatch; which led us to be directed to do an autoland in ZZZZ because the weather at the destination that the airplane would be flying were cat III. We said we would and performed the autoland. On approach we had a no land 3 message on the EICAS and a status message cue. The airplane then indicated the CAT II only on the PFD. We also saw that; as per multiple write ups; the FO's side G/S indication for the raw data portion was not in view. At about 1500 feet above the ground; the FO side glideslope came into view; but the aircraft showed slightly high on glide slope according to the raw data indication (note very slightly high; not out of any parameters; but still a bit unusual for the indication while on autopilot). Atmospheric conditions were VFR and the runway was in sight during the whole approach sequence. At about the time that the FO's raw data for the G/S reappeared; the Captain's side G/S raw data indication disappeared from view; though there was no indication of fault noted on EICAS with either of these issues. We continued the approach and the captain let the airplane land and it landed normally and tracked the centerline normally. The autoland was written up as unsatisfactory due to the loss of both raw data indications during the approach; the FO side data came back; the Captain side never did once it was gone. It appears to me that the autoland system deferral perhaps was not deferred properly as multiple failures over weeks of time suggested a problem with the system; and in the case of our monitoring of the autoland during our flight resulted in the same G/S issues on the FO side as well as a new failure on the Captain side of the raw data indications.
B747-400 First Officer reported the autoland system was malfunctioning during approach/landing.