Originally Posted by
punkalouver
C-GHLM, an Air Canada Airbus A330-300 was conducting flight AC885 from Geneve-Cointrin (LSGG) Switzerland to Montreal/Pierre Elliott Trudeau Intl. (CYUL), QC. During initial climb approximately 41 NM NNE of Lyon St-Exupéry (LFLL), France, Flight crew noticed navigation errors, was unable to fly planned waypoints and shortly thereafter lost all navigation. Flight crew advised ATC, declared a PANPAN and diverted to LFLL where an overweight landing was performed. Maintenance conducted a complete reset of the inertial reference system and aircraft completed flight to CYUL without further issues following maintenance.
Any particular reason for an overweight landing in this case?