Flat Side Up and all,
In addition to the standby (raw) airspeed indicator, there are (I believe) three IRS units with GS info on the MD11. Also, there is the possibility of getting a GS readout from ATC, and if all else fails, perhaps even assistance from another aircraft (if good VFR) - lose side by side formation to confirm airspeed.
If anyone has any further info on the Subic Bay accident, could they please post it here? Thanks.