Propeller from U.S. aircraft found in Mount Tanzawa region, Japan.
C-54 Skymaster “Sacred Cow,” features the same type of three-blade propeller found in Mount Tanzawa region of Japan. Photo courtesy of the National Museum of the U.S. Air Force
May 2018 verification of propeller location. Left to right: Kawachi Masaki, Lt Gen Yoshida (ret), and Maj Dan Moss.
By MAJ DAN MOSS, 374TH AIRLIFT WING, Yokota Air Base, Japan
When I arrived at Yokota Air Base after my Air Education and Training Command tour at Randolph in May 2017, I expected to be flying the C-130J to locations across the Pacific. Instead, I learned I would be leaving the squadron to serve as the Wing Flight Safety Officer—and then learned the Wing Chief of Safety was departing and I would be filling in for at least a year. I reluctantly stepped out of the cockpit and into a cubicle, where I spent most of my time learning about occupational and weapons safety. I desperately needed something to connect me to the flying world.
That’s when Lt Gen (ret) Kosuke Yoshida of the Japanese Air Self Defense Force contacted me. He said hikers in the mountains west of Tokyo discovered an old propeller that appeared to be from a U.S. aircraft. He had pictures of it but no coordinates and no contact information for the hikers.
The three-bladed assembly was apparently in the forested 300-square-mile Mount Tanzawa region, but we didn’t know if it was a combat loss or was due to an unknown mishap after WWII. The photo showed a badly scratched blade depicting the text DWG. NO. 6507A-0, SER. NO. RR07986, MIN. 24, MAX. 93.
The drawing number—shown as DWG—told us the blade was used on a variety of aircraft, but the serial number did not provide evidence of its origin. Our research showed this particular mountain region had no combat losses but had five aircraft mishaps from 1947 to 1958—two of those on the same day.
At the time of the C-54 incident, the Air Force averaged 37 non-combat fatal accidents per 100,000 flight hours. According to 2017 Air Force Safety Center statistics, that rate was 0.75 non-combat accidents per 100,000 flight hours.Technical orders revealed six aircraft used this blade. One was naval R5D-1 aircraft, which matched the pitch settings stenciled in the blade: MIN. 24, MAX. 93. The Navy didn’t lose any planes in the region, but the specifications, manufacturer, and technical orders for R5D-1 aircraft matched the specs for a USAF C-54 Skymaster.
We learned of two C-54 mishaps and a chartered L-1049 Super Constellation that went down carrying engines for C-54 aircraft. Severely bent and evenly damaged blade tips can mean a propeller was at a low angle of impact and a high RPM when it struck the ground. The even distribution of blade damage told us this one was likely part of a C-54 mishap.
We reviewed approximately 3,000 pages of material and scoured reports looking for clues that matched the propeller images to the incidents. A team dispatched to the sites could not locate any wreckage in the difficult terrain, making it seem as if the mystery would end without resolution.
As a Hail Mary of sorts, an online search of the propeller’s serial number revealed a Japanese blog showing the trail map of the hikers’ discovery.
The spot was a half-mile north of the area searched after the April 1950 mishap. Using an array of sleuthing tools—the hikers’ map, the original investigator’s notes, geodata from aircrew planning software, and information gleaned from the hikers’ photo—we calculated the approximate final resting place of the aircraft.
On May 23, 2018, Lt Gen Yoshida (ret) and I reached the area and soon found the propeller. Coordinates and photos confirmed it came from the April 1950 crash of a USAF C-54 from the 374th Troop Carrier Group at Clark Air Base in the Philippines.
I struggled to imagine the plane descending into the mountains, killing eight crewmembers and 27 passengers. Some of those aboard were members of General MacArthur’s staff, including an aide, the aide’s wife, and their two children. The aircrew had misidentified its location and, without ground-based backup, relied solely on internal navigation.
We reached the wreckage just before the United States celebrated Memorial Day. Although not downed in combat, this aircraft was providing diplomatic support for the betterment of the United States’ position in the Pacific and the reconstruction of Japan. The crew and passengers risked their lives to improve two nations—not as glamorous as combat but nonetheless a heroic and selfless sacrifice.
Standing on the mountain with the propeller of the downed aircraft left me grateful for how far we’ve come in safety. Similar sacrifices in my 16-year Air Force journey involved close friends, but seeing the physical evidence firsthand in the location at which it occurred was an irreplaceable moment.
We often complain about a system with too many rules and too many hoops to jump through, but never forget that this same system has saved countless lives—probably yours and mine on at least one occasion.