B-767 nav problem over Atlantic
On 1 January, a London-bound Delta Air Lines aircraft diverted to Ireland with navigation problems.
The Delta Air Lines Boeing 767-300, on flight DL-63 that departed Boston on 31 December, was bound for London Heathrow.
But, whilst en route at FL350 (~35,000 ft) over the Atlantic, the crew reported navigation problems and descended to FL290 - a normal procedure for aircraft unable to comply with transatlantic navigation requirements.
The crew then diverted to Dublin, where the aircraft landed safely. It was able to continue after about 6 hours on the ground in Dublin and arrived in London with a delay of ~6.5 hours.
It will be fascinating to learn what problems occurred to an aircraft with redundant inertial/GPS feeding a flight management system (FMS) - presumably actual navigation performance (ANP) fell below that of required navigation performance (RNP) for an Atlantic crossing.
Details from the Aviation Herald below . .