Originally Posted by
noflynomore
... There does not appear to be a facility to call MAYDAY on behalf of a third party though this is specifically allowed for in a PAN call ...
However, section 8 goes on to say in para 8.24:
"Any aeronautical station or aircraft knowing of an emergency incident may transmit a distress message whenever such action is necessary to obtain assistance for the aircraft or vessel in distress. In such circumstances, it should be made clear that the aircraft transmitting is not itself in distress."
and includes an example call, which begins:
MAYDAY MAYDAY MAYDAY
Milthorpe Tower, G-ABCD, have intercepted MAYDAY from G-BJRD... (etc.)