To ATC
29M declared, ''Pan-Pan, Pan-Pan, Pan-Pan, standby.''
is viewed quite differently to your interpetation.
''Pan-Pan, Pan-Pan, Pan-Pan,'
This is we have a problem.
One little word but it means so much.
Quite simply
don't call us we have things to do.
When we are finished with our checklists
WE will contact you.
ATC will ring the duty office with an "Aircraft Alert" and pass what details they have.
The duty officer opens the relevant section of the aerodrome manual and starts pushing buttons.
There is no room for personal opinion at this stage, just start calling people.
In the meantime the fire crew have their checklist and start deploying as per procedures.
The fire-crew and duty office will be in frequent contact with ATC to get updated info but unless the pilot can talk they have nothing to add at this stage.
The number of times "pan-pan" or "mayday" is uttered is irrelelevant. Both should be uttered 3 times by pilot as per ICAO standard phraseology and both should get a set response emergency services wise.
The words not the amount of times is the trigger for ATC to start their "checklists".