William P. Donelan enlisted (ASN: 16059612) as a Private in the Army Air Corps on 19 March 1942 at Detroit, Michigan.

Selected for the Aviation Cadet Program, he completed flight training and was commissioned (ASN: O-737552) a Second Lieutenant in the USAAF.

Underwent B-29 aircraft transition and combat crew training at Pratt Army Air Field, Kansas.

On 7 March 1945, he deployed to the Pacific Theatre of Operations and was assigned to 20th Air Force, XXI Bomber Command, 58th Bomb Wing, 40th Bombardment Group (VH), 25th Bomber Squadron stationed at West Field on Tinian in the Mariana Islands.

On 14 May 1945, he flew in the left seat as the Airplane Command Pilot aboard a Boeing B-29-30-BW Super Fortress nicknamed "Deacon's Disciples II" (serial #42-24492), tail code: Triangle-S-13.

It was one of 472 B-29 aircraft launched in a multi-group formation to bombard the industrial area of Nagoya, Japan.

No radio communication was received after take-off, and the aircraft was not seen to be in "distress." However, the aircraft developed a fire in the #2 engine and was forced to ditch south of Iwo Jima. All were lost as a result of the crash; with only his co-pilot being rescued by the crew of the USS Case (DD-370) on 27 May 1945.