Thanks H D. I agree with all the findings, the only bit I would change (which may be a translation thing) is no2,
the copilot did not try to continue to control the aircraft manually.
So, we have an a/c with two serviceable AI s, and quite capable of being flown (presumably on a full ILS on autopilot if they must) by P2.
Why would the Captain say 'that no heading indication was available'? Is the RJ100 compass system driven only by IRS1? If so, is there no standby?