Sycamore
1. Can't speak for the bus but there can be problems in some types if the aircraft is unattended, the ground power drops out and the IRS's end up on battery power.
2. No idea why but where we work on the 777 we moved away from an SOP of leaving the IRSs alone between relatively short long haul sectors and we now always do a full re-align. That might be down to tighter nav accuracy requirements these days but that is only a wild guess.
Last edited by wiggy; 9th Sep 2016 at 16:34.