I would recommend reposting some of these messages on the Tech Forum, but be prepared for more "utter tosh" comments. I'd especially like to hear the reaction to Dagger Dirk's message
Re RDMI...
The DME, at least, should have been working on the RDMI's (with manual VOR tuning).
Re TOGA
Pushing the TOGA switch doesn't do anything to the IRS's. Only the FMC position is affected (where GPS is not a valid FMC input).
Re Antiskid
Antiskid does
not equal Autobrake (two different things... although the Autobrake is dependent on a functioning A/S system.... and a functioning IRS system (unless we're talking RTO)).
If the 757 is like the 767, the Antiskid system only needs the IRS's for hydroplane/touchdown protection. I'd wager that the other antiskid functions would be ok (allowing normal manual braking with antiskid protection for the rest of the rollout).
Re triple IRS failure
It's not unheard of, but flight crew error has been the cause on at least one occasion (quick realignment at the threshold + takeoff roll started too early). I wonder if they tried ATTitude mode after they lost their displays? (This would have given them attitude and, if they entered a valid heading, VOR and perhaps a fully functioning ILS display).
Regards.
Q.