"> > map shifts
> Unlikely I'd hazard to guess, never known this to be a problem or contributory to a single fatal accident , although heard all the scare stories, but would be interested to know if they did a full alignment and the state of the IRU's."
If you've got DME along the route isn't that sufficient to stop map shift? The IRUs can be way off but DME or GPS updating overrides them doesn't it?