Date:	Wednesday 21 June 1944
Time:	23:12
Type:	Martin PBM-3D Mariner
Owner/operator:	VP-16 US Navy
Registration:	45216
MSN:
Fatalities:	Fatalities: 12 / Occupants: 12
Aircraft damage:	Destroyed
Location:	By 15° 06’ N 139° 20’ E, west of Mariana Islands -   Pacific Ocean
Phase:	Combat
Nature:	Military
Departure airport:
Destination airport:

Narrative:
In the evening of 21 June 1944 US Navy Destroyer Divisions 92 (USS Boyd, Bradford, Brown and Cowell) and 104 were proceeding independently west of Marianas, about ten miles apart on parallel course, to rendezvous with a fueling group when at 2217 hrs radar contact was made with several unidentified aircraft, bearing 130°, distance 60 miles. The destroyers formed a column but at 2223 hrs the contact faded. At 2227 hrs another contact was made with one unidentified aircraft, bearing 055°, distance 30 miles.

At 2234, 2242, 2255, 2258 hrs the destroyers changed course to evade and give all ships clear firing bearing. Another radar contact made at 2241 hrs faded 5 minutes later. The closer unindetified aircraft was now orbiting close to the formation out of range, but then started a low level approach and at 2309 hrs it was at four miles, bearing 215° and closing. Permission to open fire was asked and granted if the plane approached within 10,000 yards. The plane continued its approach directly toward the division and fire was opened at 2310 hrs at about 8,000 yards, while the destroyer executed turn to avoid anticipated torpedo. All four destroyers fired, expending a total of 262 5in and 132 40mm shells and at 2312 hrs the aircraft was shot down by 15° 06’ N 139° 20’ E.

The Brown was sent to investigate crash. It found a wing float painted characteristic light and dark blue as US Navy planes. The crew attempted to get pontoon aboard for further identification but it proved too heavy to handle. The body of a man was reported sighted with a yellow life jacket similar to the one worn by Amerian aviators. An attempt was made to recover it but the ship was unable to find it again. A pilot aboard the destroyer saw a deflated rubber boat with C02 bottles and recognized it as US. A window curtain with spring roller marked in USA was picked up. Despite thorough search of area, no other identification material and no survivor was found. It was concluded that the aircraft had been a friendly PBM.

Earlier during the day the division had made contact with friendly patrol planes not showing IFF, and had been reminded at 1630 hrs that friendly submarines and search planes with IFF inoperative were in the area. This was reminded to the ships when the evening calls were made. A ship of DevDiv 104, USS Hunt, reported that the motor sounds of the plane motirs sounded familiar, and the Boyd was ordered to broadcast on all aircraft voice circuits "Any search plane investigating surface ships get away from the area because your IFF is not working", while Cowell reported hearing a test call on TBL. All ships of DesDiv 92 were asked if they had any indication that contact was firendly. All replied negative.

In DesDiv 92 report it was believed that the PBM thought DesDuvs 92 and 104 were enemy and was making an attack on DesDiv 92, but it is possible that he was investigating DesDiv 104 and was unaware of the presence of DesDiv 92. A message reporting that a search plane was investigating a radar contact was received in the Boyd at approximately the instant of opening fire.

The conclusion of the report was that in the situation described above the matter of self preservation demanded to DesDiv 92 to open fire: "This tragic indident is deeply regretted but it is felt that in the circumstances no alternative was open to Commander Destroyer Division 92 to act other than as he did."

The lost Mariner was from VP-16. This unit was operating from the open sea off the roadstead of Garapan Harbor, Saipan, since the 18th, being serviced by the USS Ballard first and then the USS Pocomoke. Seven aircraft of this unit were flying night patrol operations this night and one, 16-P-13 (PBM-3D Buno 45216), did not return. His last transmission to the base was "Investigating suspicious vessel." His fate was unknow until the 23rd, when the report of the shooting down of a PBM by DesDiv 92 was received.

Crew (all missing):
Lt.Cmdr Harry R Flachsbarth, USNR (pilot)
Ens Lyman E. Benson, USNR
Ens Larsen G. Ruth, USN
ARM3c Cecil Hertford Wiggs, USNR
AMM3c Austin Earl Hoskins, USNR
AMM3c George Plant, USNR
AMM1c Robert Eugene Wise, USNR
ARM3c James Terry Greenfield, USNR
S1c Lee Roy Douglas, USNR
AMM3c Alexander Hilton,Jr.
AMM3 Ray R Moorman, USN (not in VP-16 war diary, but in all other sources)
AOM3c Wallace Blackwell Grant, USNR

All are commemorated on the Tablets of the Missing at Manila American Cemetery, Philippines.

Quite a great deal of trouble was experienced by VP-16 with IFF equipment during the first 10 days of operations at Saipan because of the following reasons:
(a) Rough water take-offs and landings with the heavy loads on the open sea on the leeward side of Saipan undoubtedly jarred the IFF equipement out of adjustment.
(b) the IFF equipement had apparently not been properly serviced by Hedron, Fleet Air Wing Two, at Kaneoke Bay, T. H.
(c) Although the proper equipment for testing and checking the IFF was on board the USS Pocomoke, it had not been set up for use and no one on board was qualikied to set it up. This was overcome when ACRT Parry arrived on board and set up a test bench for IFF. The delay on his arrival coupled with the failure to provide similarly qualified people in the PATSU, was the direct cause of the loss of the above crew.

COMDESDIV 92, Report of shooting down of friendly aircraft on 6/21/44, West of Marianas (http://www.fold3.com/image/277072603/#277072467/)
VP-16 War Diary, June 1944 (http://www.fold3.com/image/279790195/#279790176/)
http://www.vpnavy.com/vp16_mishap.html
"The fighting flying boat: a history of the Martin PBM Mariner", by Richard Alden Hoffman. ISBN 1-59114-375-6
https://www.abmc.gov/search/node
http://wikimapia.org/#lang=fr&lat=15.100000&lon=139.333333&z=6

Date/time	Contributor	Updates
14-Nov-2010 11:55	ASN archive	Added
12-Jan-2018 15:22	Laurent Rizzotti	Updated [Date, Time, Operator, Total fatalities, Total occupants, Location, Country, Phase, Source, Narrative]
03-Jul-2020 15:12	Digger	Updated [Operator, Operator]