Hi Brian,
I continue to find friendly fire incidents here and there, and will report them here.
Here are two, both for 49th FG USAAF:
31 October 1944:
To start the day wrong, the ack ack shot down a P-38 from the 7th squadron while it was landing. There was a strafing raid in progress, but that was a scant excuse for the tragic incident.
Source: http://www.flyingknights.net/unit/oct44b.htm
The pilot may have been 2nd Lt Robert W. Searlight who was KIA this day but I have no confirmation of this, or any serial.
4 April 1942
See the following link: http://www.armyairforces.com/forum/m_89349/tm.htm
It describes a raid on Darwin. Returning intercepting US fighters were fired on by Australian AA fire and two shot down, with one pilot KIA.
Best regards
Laurent