Doug,
Since the was Airlifeline, Angel Flight Mid-atlantic, Southest, West,
Lifeline pilots..... They all used different Call signs or none at all.
The organizations got together in late 1990s and decided since they had
a common mission they needed a common call sign. They applied for and
received the Compassion (CMF) call sign. This way all of us doing the
same thing are identified the same to ATC.
LifeGuard is for air medical ambulance only.
Michelle

Doug Carter wrote:

I just read the procedures handbooks for two different Angel Flight
organizations and noticed that one recommends the call sign
"Compassion" and filing flight plans with the identifier "CMFxxx" and
the other, "Angel Flight" and the identifier "NGFxxx."

Having heard "Angel Flight xxx" for years I was surprised to learn the
"Compassion" term apparently has been around since 1999. Neither
seems to be mentioned in the AIM; "Lifeguard" is, but that is a
different operation (air ambulance).

Any particular reason for multiple terms other than different
organizations marching to different (possibly politically correct)
drummers?