Second Lieutenant McKanna was the pilot of B-17F Flying Fortress #42-3503, serving with the 399th Bomb Squadron, 88th Bomb Group from the Walla Walla Army Air Base, Washington.
While returning from a training mission over the Boardman Bombing Range, apparently an engine fire led to a gasoline explosion in the port wing, resulting in a catastrophic disintegration of the aircraft at 20,000 feet and it crashed, seventeen miles east of Arlington, Oregon, causing the deaths of all eight airmen aboard.
The other service members who perished:
2nd Lt. James R West, Co-pilot 2nd Lt. Robert J Miller, Bombardier Sgt. Jesus P Diaz, Radio Operator Sgt. Richard H Laird, aerial gunner Sgt. William V Mac Dowell, Flight Engineer PFC Chester W Shultz, aerial gunner Pvt. Peter J Nardo, Asst. Radio Operator