Lifeguard flights: How to file a flight plan?

"Peter R." wrote in message
...

Recently, I placed my name in a pool of pilots who volunteer for organ
transplant patient flights. Since there is a time deadline involved, am I
correct to assume that these flights are eligible to fly under the
"Lifeguard" callsign?


Yes.



Does one have to file a flight plan under this callsign or does one simply
inform ATC when receiving the clearance? If it is easier to file using
the
callsign, what do I put in the AIRCRAFT ID field of the flight plan?


Put an L in front of your N number, LN1234A for example.