Hang on, RT'ing the F'in Q again.... a dual failure is highly unlikely, and would in general be down to a total electrical failure with an additional failure of Transponder 1 and VHF 1 at the same time... in which case comms problems would be rather low on my list of priorities. Then VMC to nearest suitable from altitude would become a probable option. Normally, dispatch with one of the 2 Txpndr systems is allowed (if at all) only if it is NOT the system which will remain when the aircraft is on battery power only; usually anything beginning with "1."
So re-reading the scenario above, even allowing for a lower-order freak five system failure (3x VHF, 2x ATC Txpndr and a bonus of 2x HF if fitted..) I have the distinct impression that certain other agencies might take a close interest in the progress of the flight, and the "Interception Procedures and Signals" page would be frantically reveiwed. I'd certainly welcome the attention...
Anyway, what is the International Signal for "Hang on 10 seconds whilst I get the book out?"
£6
[ 04 August 2001: Message edited by: Sick Squid ]