Home » Aviation » Curiosity and High-tech Sonar Uncover Lost WWII Torpedo Bomber 72 Years Later


Curiosity and High-tech Sonar Uncover Lost WWII Torpedo Bomber 72 Years Later

The remains of the missing Grumman TBM-1C Avenger. Photo Courtesy of Scripps Institution of Oceanography

The remains of the missing Grumman TBM-1C Avenger. Photo Courtesy of Scripps Institution of Oceanography

For 72 years, it was missing in action. The Navy torpedo bomber rested on the sandy bottom off Palau’s coast, its fuselage violently broken from anti-aircraft fire amid heavy fighting of World War II.

Its presence there in the South Pacific went unnoticed until this spring, when a volunteer team of divers, historians and oceanography experts found the wreck. After some research and calculations – plus some high-tech sonar – the team determined the aircraft was a three-man TBM-1C Avenger that had crashed during a bombing run in July 1944.

That single discovery, while a drop in the bucket of more than 17,000 naval wrecks, is among the latest to begin the long process of finding answers about what happened to the Avenger and, perhaps, closure for the air crew’s survivors.

It began when a curious Patrick J. Scannon, an aviation buff, scuba diver and physician who founded a California company that discovers and develops antibodies. But naval history is his passion, particularly finding World War II wrecks in the South Pacific, where the pristine blue-green waters can mask graveyards of worn warbirds long forgotten by time.

Grumman TBM-1C Avenger torpedo bomber in 1944. US Navy Photo

Grumman TBM-1C Avenger torpedo bomber in 1944. US Navy Photo

In 1993, Scannon joined a diving friend to locate an armed Japanese trawler sunken off Palau, near the Philippines, on July 25, 1944, by former President George H.W. Bush, then an ensign piloting a TBF Avenger bomber. He found a broken aircraft wing of a downed Army Air Corps B-24 that hadn’t been recorded, and he soon searched for other aircraft wrecks off Palau. In 2000, he founded The BentProp Project “to make sure that that kind of sacrifice was not forgotten,” he told USNI News. The group counts on two-dozen active volunteers and donations to support and fund the work, which “is not an insignificant effort.”

Discovery of wreckage is just the first step to determine what happened to the aircraft. “It becomes quite a detective story,” said Scannon, who is withholding the location and unit details to secure the site and protect the aircrew, whose identification and names are yet to be verified by the Department of Defense.

As luck would have it, the Avenger Scannon’s team found was identified with the help of detailed squadron logs and other historical records including Japanese archives. With those details, the team was able to calculate possible flight paths and glide slopes to identify potential wreckage areas.

Advances in technology and data mining helped locate the bomber. Divers used a REMUS 100 autonomous underwater vehicle (AUV) and high-frequency side-scanning sonar in the shallow waters about 80 to 90 feet deep. Specialized sensors helped draw an image of the ocean floor.

The remains of the missing Grumman TBM-1C Avenger. Photo Courtesy of Scripps Institution of Oceanography

The remains of the missing Grumman TBM-1C Avenger. Photo Courtesy of Scripps Institution of Oceanography

“We had six different aircraft we were looking for in the particular area,” said Eric Terrill, a diver and oceanographer with Scripps Institution of Oceanography and director of its Coastal Observing Research and Development Center. Over several weeks, the diving team did numerous side-scanning surveys, using historical records, after-action reports and other analyses to find probable areas of wrecks. “There were just so many targets,” he said, from the anomalies in the sonar images.

Their adrenaline pumped when they dove to a possible wreck for the first time, Terrill said. What he saw “was clearly man-made,” he said. “It was humbling. You’re excited that we’ve been successful, but you are really coming to hallowed ground.”

The Avenger had settled into the sand. For decades, it has provided a harbor for sea life, its surfaces broken or dented and mostly covered by algae and corals.

The bomber, Terrill and two engineers later estimated, had been flying at about 4,000 feet and was descending at a high angle after it lost a wing from anti-aircraft fire. It violently crashed into the water based on the wreckage footprint spread across a 20-meter by 20-meter area. The fuselage was split in half, and “we could see substantial fire (damage) in the main debris field,” Scannon said. Divers could see the cockpit cage and gun turret was thrown from the airplane by the impact. A wing had broken off, but the team later found it 900 meters away. Did any of the crew manage to bail out, or survive? Those questions remain unanswered.

“A crash site, even if it happened 50 years ago, is still something of a detective’s work,” Robert S. Neyland, who heads the undersea archeology branch head at Naval History and Heritage Command in Washington Navy Yard, told USNI News.

The remains of the missing Grumman TBM-1C Avenger. Photo Courtesy of Scripps Institution of Oceanography

The remains of the missing Grumman TBM-1C Avenger. Photo Courtesy of Scripps Institution of Oceanography

Once it was determined it was an Avenger, the BentProp team completed the site survey, compiling historical documentation and after-action reports that Project RECOVERY gave to the Defense POW/MIA Accounting Agency (DPAA) in April. Project RECOVER is a collaboration among BentProp, the University of Delaware researchers and Scripps/University of California-San Diego. The team works under an agreement with DPAA to share site data, as well as work with the U.S. government to conduct missing-in-action related searches.

“To proceed with forensics, all three agencies will be involved,” Scannon said, referring to DPAA, Naval History and Heritage Center and Palau’s Bureau of Arts & Culture, “and it’s a true forensic recovery. It’s treated in the same manner as crime scenes are treated. It’s very formal.”

The Hawaii-based DPAA would determine whether to recover any remains or artifacts, a process that could take years. Although Vietnam remains a priority for the agency, DPAA plans to deploy 24 investigation teams and 57 recovery teams to 16 other countries including Palau during fiscal 2017, according to a June 23 briefing at the annual POW/MIA Families conference in Virginia. The agency, in its second year of a restructuring, is under pressure to step up its efforts and show results. Some 83,000 Americans remain missing since World War II, which accounts for more than 73,100 MIAs.

The remains of the missing Grumman TBM-1C Avenger. Photo Courtesy of Scripps Institution of Oceanography

The remains of the missing Grumman TBM-1C Avenger. Photo Courtesy of Scripps Institution of Oceanography

Among DPAA’s latest focus is collaborating more with private groups and researchers, which could benefit from continuing interest in naval history particularly among local residents with in-depth knowledge of local waters and history. “There are groups like BentProp and others that go out and they take it as their mission,” Neyland said. “In most cases, I’d say it’s a big help.”

“BentProp is very professional. They use principles of archeology and have archeologists involved,” he said. “With a long list of wreck sites, “we have to pick and choose what we have time to work on. So what they do is very, very helpful to us.”

The Navy routinely works and shares information with the agency, which would determine whether the wreck site is explored further. On the latest TCM-1C wreck, “it may be an outcome in the future,” Neyland said. But no decision is yet made.

Just how many aircraft – U.S., allied or Japanese – and ships are in those Palau waters isn’t clear. The command’s underwater archeology branch has the lead for managing more than 2,500 shipwrecks and 14,000 aircraft wrecks globally, according to the Naval History and Heritage Command. On any given day, Neyland said, he and NHHC teams are working through numerous investigations, historical records and data, from a possible wreck in the Arctic to downed aircraft in Florida and plane in Montana. “Even though these things come up, there’s usually not a quick resolution,” he said.

Every wreck is considered U.S. government property, hands-off for anyone other than official or permitted recovery efforts, if undertaken. “These wreck sites are often the final resting places of sailors who paid the ultimate sacrifice,” the command states on its website, and these “carry significant historical importance or may contain hazards such as oil or unexploded ordnance.”The Navy maintains jurisdiction and responsibility for underwater wrecks, said NHHC spokesman Paul Taylor.

A recent revision to federal law that preserves sunken military wrecks – in effect since March 1 – requires permits to do any “intrusive activities” at a sunken wreck for “archaeological, historical, or educational purposes.” Wrecks “are not to be disturbed, removed, or injured, and violators may face enforcement action for doing so without authorization,” officials said last year in announcing the policy change. Also, “activities such as fishing, snorkeling and diving which are not intended to disturb, remove, or injure any portion of a sunken military craft are still allowed without the need for a permit.”

Project RECOVERY’s work is far from over. “We have a very long case list … that’s now 100 sites long,” Terrill said. “We’ve been cataloging a lot of search areas.” Newer technologies and sensors aid efforts and create more accurate data for ongoing searches and analyses, he added. Every wreck search, investigation, remains and artifact identification and recovery takes time, and that work requires funding. The Avenger project was covered by donations and funding from Air Force Heritage Flight Foundation founder Dan Friedkin.

BentProp has joined in 17 expeditions since 1999 and helped locate several crash sites where, in one case, four missing-in-action service members were recovered and repatriated. The group conducts “flag ceremonies” on the water to honor those lost. Whatever the military’s decision with this latest Avenger discovery, “we hope and look forward to the day where we can deliver these flags” to the relatives,” Scannon said. “We think it’s important to always have the families in mind.”

“It’s a very somber kind of adventure,” he said, “because you never lose sight of what we are doing.” Family members he’s met often are as emotional as if their loss was recent, he added, noting “almost every home I’ve been to has had a place of honor for their missing.”

  • Treeman

    Extremely well written and interesting article!

  • ULISES VELEZ

    THE HI-TECH HELP TO MANKIND.

  • Curtis Conway

    If all could embrace such a mindset.

  • Secundius

    One of WW2’s Great Carrier Planes…

    • John B. Morgen

      It sunk many Japanese warships and German U-boats during World War II.

  • The TBM was built under license by Eastern Aircraft Division of General Motors, not by Grumman.

    • Secundius

      True Enough, but the “Avenger” was Conceived, Designed and FIRST Built by Grumman…

      • Indeed, but in the interest of accuracy and perhaps educating the uninitiated, I wanted to make the point. Grumman’s bird was known as the TBF; and, by the end of the war there were more TBMs built than TBFs.

        • Secundius

          Most “Warplace” enthusiasts, First Looking at A Warplane are going to see the Parent Company that Made the Designed the Plane, Rather then Who Actually Made It. Keep in mind the M1 Garand, though Designed by Springfield Armory. Was ALSO Manufactured by International Harvester during WW2. But Gun enthusiasts, are ONLY going to see Springfield Armory…

  • John B. Morgen

    Leave it alone because the government or anyone else are not going to find much in terms of human remains. It is [not] worth the time or the funds, just make a note about the wreck.

  • Congratulations to all who investigated this case. The families of over 83,000
    brave American heroes who remain missing from all our conflicts dating back to
    WWII should know that many are working to locate, recover, and help identify our
    lost heroes to achieve the closure for the families that they deserve.

    The Joint POW/MIA Accounting Command (JPAC) was finally disbanded after
    an avalanche of scandals were exposed by NBC, CBS, Fox News, NPR, the AP, and
    Stars and Stripes. Multiple government investigations then found gross
    mismanagement and a total lack of leadership. The American public and families
    of our lost heroes channeled their anger, frustration, humiliation, and feelings
    of betrayal to demand the immediate removal of those responsible for what the
    the Chairman of the Joint Chiefs of Staff, General Martin Dempsey, testified was
    “Disgraceful”.

    A “new” Defense POW/MIA Accounting Agency (DPAA) was created to replace the
    scandal plagued JPAC. Sadly, the government’s idea of the massive reform
    necessary was a superficial name change of the organization and re-shuffling the
    same poor executives and laboratory managers to new desks and titles in a brand
    new $85 million dollar building in Hawaii. Before quitting in less than a year,
    the new director of DPAA discovered that the DPAA lab was just as inept in a new
    building as they were in the previous facility and DPAA began depending on the
    Armed Forces DNA Identification Laboratory in Delaware for identifications.

    In 2015, the DPAA lab produced a grand total
    of 70 identifications at a gross cost of almost $2
    million per identification! This was a whooping one
    more identification than JPAC’s proven dysfunctional system produced the
    previous year! Five identifications in 2015 were from remains discovered by
    a private group at a construction site . Another identification was the result
    of a family filing a Federal lawsuit to force DPAA’s management to act after
    JPAC’s own investigation matched the missing serviceman’s identity with a
    precise burial location! But half of the 70 identifications were from remains
    turned over by North Korea in 1991 that had been sitting on the JPAC/DPAA
    Laboratory shelves for 24 YEARS! Disgraceful!

    Due to antiquated methods and dysfunctional management there is a backlog
    of over 1,400 sets of remains of American service men and women sitting in
    cardboard boxes at DPAA awaiting identification right now. The AVERAGE time for
    identification after remains are received in the DPAA/JPAC laboratory is ELEVEN
    YEARS! Disgraceful!

    The same group of serial offenders responsible for this ineptitude that
    brought us multiple outrageous scandals including phony “arrival home”
    ceremonies and multiple investigations into fraud, waste and abuse of government
    funds remain in the “new” DPAA. The JPAC Scientific Director was reassigned to
    be in charge of “partnering with private groups”. Does this mean that he hands
    out government contracts for work that DPAA should be doing? Disgraceful!

    Meanwhile the JPAC/DPAA management mantra of “Delay, Deny, and wait for the
    families to Die” continues. The current response time for basic information to
    families and researchers under the Freedom of Information Act is over ONE YEAR!
    Federal law requires this information to be provided within 20 days, which DPAA
    routinely violates without consequences. Disgraceful!

    Anyone with any management experience knows that the entire operation that
    was JPAC should have been deconstructed, brick by brick. Such needed massive
    reform simply did not happen. Just when families of our missing servicemen and
    women thought things could not get worse, it did. The same infectious disease
    of JPAC arrogance and lies to the families of American heroes took root all over
    again at DPAA. This incredibly dysfunctional organization continues and has been
    added to the VA Hospital, Dover Mortuary, Arlington Cemetery, and the Viet Nam
    Unknown misidentification debacles. Disgraceful!

    • John B. Morgen

      Gee, I knew someone who worked for this organization, but as a military historian.

    • Secundius

      When in Some Cases you ONLY have a “TOOTH”? $2-Million IS Cheap, considering that, that Unidentified Person DIED also most 75-years ago. Their STILL Finding People that Died during the Revolutionary War 239-years ago and the ONLY “ID” was a Belt Buckle or Button…

  • John B. Morgen

    Both the TBFs and TBMs were outstanding torpedo bombers. In fact, some of them served into the 1950’s as ASW aircraft for foreign navies.

    • Secundius

      The British called them “Tarpons”…

      • John B. Morgen

        That’s correct, but the British also changed the Wildcat F4Fs’ name to Martlets; yet, the British did not changed the Hellcat F6Fs’ name. All three aircraft were designed by Grumman.

        • Secundius

          Grumman DID Make Great Naval Carrier Aircraft’s. But then again, so did Chance-Vought…

          • John B. Morgen

            Yes the F8U Corsair fighter, another outstanding naval fighter.

          • Secundius

            I think the Chance-Vought F5U Flying Flapjack, would have made a Great Naval Fighter. If it wasn’t for it ODD Design. They should Dust-Off the Blueprints and Update the Design with Jet Engines. And Use It as a Super-Stol Ground Support Aircraft, or a Possible Replacement of the A-10C Warthog…

          • John B. Morgen

            Indeed, the Chance Vought XF5U-1 Flying Flapjack or Flying Pancake was the last propeller designed aircraft built by the company. Unfortunately, the program was killed by the advent of jets, and jets were the future for seapower. By December 1945 the Royal Navy had conducted trial flight deck carrier landings with Vampire jet fighter aircraft on board the HMS Ocean. The Flying Flapjack or Pancake was cancelled in March 1947.

            The aircraft would not be a good replacement for the A-10 because the Flying Flapjack or Flying Pancake was limited to two 2,000 pound bombs, and two 20mm guns. However, it would have been an outstanding naval fighter, for its speed and fast maneuver abilities in the air.

          • Secundius

            Yeah, but remember the F5U-1, was a WW2 Design Carrier Plane. The TBF/M “Avenger” Also had a 2,000-pound Ordnance Payload Capacity. In most Air Forces, in WW2, 2,000-pound made YOU a “Medium Bomber”. With Current Level of Technology. You Could Probably Increase Lift Capacity to at Least 10,000-pounds. The Douglass A-1 Skyraider, had a Lift Capacity of 9,000-pounds. Buy WW2 Standards that made the Plane a “Heavy Bomber”. Actually the Last Purpose Built Radial Piston Engined Powered Navy Aircraft was the Grumman S2F Tracer/Trader/Tracker, in 1954…

          • John B. Morgen

            Based on World War II standards for the United States bomber aircraft there were three classifications: first the heavy bombers; second the medium bombers; and third the light bombers.
            The heavy bombers consist of the B-17 which carried between 6,000 to 12,800 pounds of bombs. Next the B-24 carried 8,000 pounds of bombs, and last heavy bomber was the B-29 which carried 20,000 pounds. These are the maximum bomb loads.
            The next group was the medium bombers, the B-25 carried 4,000 pounds of bombs, and the B-26 carried between 3,000 to 4,000 pounds of bombs.
            The last group was the light bombers, the British built Mosquito but Americans used it carried 4,000 pounds of bombs. The Avenger carried 2,000 pounds of bombs, next the Dauntless carried 1,200 pounds of bombs, while Helldiver just carried 1,000 pounds of bombs. I did not include the Skyraider because it arrived after the war had ended.
            As for last radial piston engined powered naval aircraft, are you referring to carried based aircraft?

          • Secundius

            Well Technically, you could Include the North American AJ-1 Savage, that entered service in 1950? With 12,000-pound Ordnance Load, the ONLY Problem being that also had a Centerline Turbojet for Dash Speed capabilities. But I was Talking about Wasp Radial Piston Powered Planes Only…

          • John B. Morgen

            No you could not because historically the AJ-1 Savage was a post-World War II carrier bomber. Yet, the A-1 Skyraider, F8F Bearcat, FR-1 Fireball and the F7F Tigercat were designed during World War II but were also too late to see any action against the Japanese. The Royal Navy had the same problem with their new carrier aircraft; for example, the Sea Fury; an outstanding naval fighter.

  • Kim Chul Soo

    Does the “recent revision to federal law” mean U.S. wrecks? How about foreign military wrecks in U.S. waters?

    • Secundius

      It’s a Revision of Application of Salvage Law and the Law of Finds to Sunken Shipwrecks, Amendment 92…