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  P-38J-15-LO "Cillie" Serial Number 42-104161 Tail Number 132
5th AF
475th FG
431st FS

Pilot ┬áCaptain William S. O'Brien, O-729890 (MIA / KIA) CA
MIA  August 4, 1944 at 12:00pm
MACR  7342

Aircraft History
Built by Lockheed Aircraft Corporation (LAC) in Burbank. Constructor Number 2995. Delivered to the U. S. Army Air Force as P-38J-15-LO Lightning serial number 42-104161. Disassembled and shipped overseas to the South West Pacific Area (SWPA) and reassembled.

Wartime History
Assigned to the 5th Air Force (5th AF), 475th Fighter Group (475th FG), 431st Fighter Squadron (431st FS) "Hades". Squadron number 132. Nicknamed "'Cillie". When lost, engine V-1710-91 and V-1710-89 serial numbers A-038992 and A-038028. Armed with 20mm cannon serial number 124313 plus .50 caliber machine guns makers unknown serial numbers 939493, 1074366, 1075416, 1075319.

Mission History
On August 4, 1944 at 9:00am took off from Mokmer Drome on Biak piloted by Captain William S. O'Brien as one of sixteen P-38s from the 431st FS on a mission to escort B-24 Liberators bombing Liang on Ambon Island. At 10:30am, the P-38s rendezvoused with the bombers. Also escorting were P-38s from the 49th Fighter Group, 9th Fighter Squadron. At 11:40am arrived over the target area at 20,000', the weather over the target was poor with all of Ceram covered by solid overcast from 1,500' to 13,000'. At 11:50am spotted enemy aircraft and released drop tanks to intercept.

While chasing an enemy fighter, possibly a Ki-61 Tony, O'Brien suffered an aerial collision with both aircraft crashing in flames with no pieces larger than the tail section observed falling over Ceram roughly eight miles southeast of Piroe. Last seen by 2nd Lt. Kenneth F. Hart. When this aircraft failed to return it was officially listed as Missing In Action (MIA).

Statement of 2nd Lt. Kenneth F. Hart via MACR 7342 page 4
"...I cut across and passed them trying to catch up with Captain O'Brien, who was chasing an unidentified enemy airplane alone. I almost caught up with him twice, but he cut sharply into me and I could not stay with him. The third time I about caught him, I lost sight of him when he and two of the 9th Fighter Squadron flights made a pass at a Nip. A few minutes after I lost sight of Captain O'Brien, I noticed southwest of where I had lost him, the after effects of a mid-air collision at 17,000 feet. Very near there was an opened parachute floating down at approximately 14,000'. As near as I can determine this action was in the vicinity southwest of Piroe about eight mies."

When this aircraft was reported as missing, search efforts were coordinated by Major Thomas B. McGuire. The next day on August 5, 1944 a search by eleven P-38s led by Major Thomas B. McGuire was flown over the area. Due to a severe weather front and low overcast over the western end of Ceram, they were unable to reach the search area. Another search was scheduled, but unclear if it was ever flown.

O'Brien was officially declared dead the day of the mission. He earned the Air Medal with three Oak Leaf Clusters and Purple Heart, posthumously. O'Brien is memorialized at Manila American Cemetery on the tablets of the missing.

USAF Serial Number Search Results - P-38J-10-LO Lightning 42-104161
Missing Air Crew Report 7342 (MACR 7342) created August 6, 1944
American Battle Monuments Commission (ABMC) - William S. O'Brien
FindAGrave - Capt William S O'Brien (tablets of the missing)
Charles Lindbergh and the 475th Fighter Group

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Last Updated
February 18, 2020


Tech Info

Aug 4, 1944

1 Missing
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