Originally Posted by
sonicbum
Correct, but a PAN does not allow You to deviate from the acknowledged clearance, hence a MAYDAY is required.
I have seen many times in the sim before "mayday engine failure climbing 4000ft to <waypoint used for EOSID>" ... only problem is the waypoint was created by the airline for the MCDU/FMC.
As for sonicbum, if I need a change in heading, speed or altitude, for whatever safety reason, I am going for it with or without the support of ATC.