I found today the 440th TCG USAAF webiste.
Two case that may interest you:
5-6 June 1944: don't know if you wiull consider it.
"On the first Normandy parachute mission one aircraft of another Group was destroyed and several were killed and wounded when a trooper's rifle discharged as he was boarding. The round hit a Gammon grenade of a trooper already aboard setting off a tremendous explosion in the aircraft."
Sounds more of an accident than friendly fire to me, but it will be your choice.
http://www.440thtroopcarriergroup.or...fullbeck.shtml
8 April 1945: two C-47 of 97th TCS destroyed on the ground in Germany by two "German" P-51. More details at
http://www.440thtroopcarriergroup.or...yseventh.shtml