SHARE

A senior Marine with over 1,200 hours of flight time was the first to see the smoke.

No one onboard Swift 12, a Marine Corps MV-22 Osprey, saw the actual crash of its sister ship, Swift 11, which killed five Marines on June 8, 2022, on a desert range near El Centro, California. But within moments, a crew member on the second Osprey spotted a tall column of smoke, service officials said Friday.

The pair of Ospreys were from Camp Pendleton, where they were assigned to Marine Medium Tiltrotor Squadron 364, a unit known since Vietnam as the Purple Foxes. The two aircraft were practicing formation flying and aerial gunnery together on a remote desert range known as R-2512.

Aboard Swift 12, a senior crew chief had been firing the Osprey’s .50 caliber machine gun off the rear ramp of the tiltrotor plane at a target 200 feet below when he saw the smoke.

“Hey, there’s fire at the five [o’clock],” the Marine called into the plane’s intercom.

A smoke column over 500 feet tall was burning into the air. Watching the smoke, the crew suddenly realized they’d lost track of Swift 11. 

“This isn’t a good feeling at all,” said one Marine over the plane’s intercom. Within seconds, the Osprey was over the fire and could see the debris. The plane’s senior pilot finally said what all four Marines were thinking: 

“Yeah, that’s them.”

Helicopters photo
A Marine Corps command investigation found that the crew of Swift 11 made no errors and could not have prevented the crash that killed all five Marines onboard in June 2022. The root cause of the accident was a dual hard clutch engagement, investigators found, a mechanical failure that has occurred on other Ospreys, flown by both the Marines and the Air Force. (Airman 1st Class Jennifer Zima/US Air Force).

The dual hard clutch engagement mystery

In a 400-page report released Friday, July 21, Marine investigators confirmed that Swift 11 suffered a fatal engine failure known as a dual hard clutch engagement, or HCE, which destroyed the Osprey’s right motor and caused “an unrecoverable departure from controlled flight and the tragic crash.”

The pilots and the crew, the report found and Marine officials emphasized, were not to blame. Nor, the Marines say, was there any oversight or mistake in the maintenance of the plane on Camp Pendleton. 

The report walks through every detail of the flight, from the age of the Osprey’s engines to how many hours of sleep the crew got the night before. The fire that consumed Swift 11 in the minutes after it crashed was so intense that it destroyed the onboard flight recorder, so there is no record of what happened on board the doomed Osprey.

But the report does contain the statements of the pilots and crew of the second Osprey on the flight, Swift 12. Those personal statements detail the full-throttle response of nearby military aircraft to rescue the doomed crew and paint a powerful picture of the Marines aboard Swift 12 pushing through the duty of overseeing the site once the deaths of their friends were confirmed.

The crash resulted in the death of Captain Nicholas P. Losapio, Captain John J. Sax, Corporal Nathan E. Carlson, Corporal Seth D. Rasmuson, and Lance Corporal Evan A. Strickland. 

“There were no prior indications of an impending dual HCE event, no steps that [pilots Losapio or Sax] could have taken to prevent its occurrence, and no means of recovery once the compound emergency commenced,” the report said.

Dual hard clutch engagements — which can cause an Osprey engine to seize and shred itself during flight — have plagued the Osprey fleet. Both the Marines and Air Force fly the tiltrotor aircraft, and both services have reported HCE events. 

Statistically, the failures are rare, the report said, with 15 HCE failures reported in 680,000 flight hours across both services, 10 of which occurred within 3 seconds of take-off (Ospreys take off vertically, like a helicopter). Failures in flight, like the one that struck the Pendleton Osprey in June 2002, are rarer but nearly always catastrophic.

Subscribe to Task & Purpose Today. Get the latest military news and culture in your inbox daily.

The Air Force briefly grounded its Osprey in 2022 but resumed flying soon after. A pair of Air Force Ospreys might have even flown the US Ambassador out of Ukraine during the opening days of the Russian invasion. But while the failure is rare, engineers have yet to solve why it occurs at all, a mystery both unique in military aviation and maddening to those responsible for the aircraft.

“The root cause of HCE remains unknown,” the report says. In a maintenance update issued in February 2023, both Air Force and Marine Osprey units were instructed to replace an engine part known as the quill assembly. This change, the Marine Corps said in a statement, should reduce the likelihood of an HCE by 99%.

In the newly released report, the commander of the Purple Foxes, whose name is redacted, said the pilots of Swift 11 were excellent Marines.

The aircraft commander, Losapio, he said, flew under the callsign of “sloppy.”

“Sloppy is a phenomenal officer and pilot,” the commander, a former Huey Cobra pilot, told investigators. “His reputation precedes him. He is just a stellar individual.”

Swift 11’s newer copilot, Sax, had worked for the commander at a previous assignment and was quickly developing his own reputation as a top flyer. “He was relatively new and he had only been in the fleet a year,” the commander recalled. “He was leaps and bounds ahead of his peers in terms of capability and stick control. I mean, he really was a natural stick and his work ethic was exceptional.”

A smoke plume in the desert

Along with describing the mechanical failings and absolving the crew of blame for the crash, the command investigation released on July 22 lays out the final flight in minute-by-minute detail through the eyes of the pilots and crew of both the second Purple Fox Osprey in the air that day and other helicopters that were training on El Centro ranges that day and responded to the crash.

On the day of the flight, the two Ospreys left Camp Pendleton just before 9 a.m., 30 minutes late, after waiting out low clouds. In the rear of the plane, the crew had brought 1200 rounds of .50 caliber ammo to fire from the Osprey’s main gun, an M240 Ramp Mounted Weapon System, or RMWS. Marine Ospreys fly with two pilots and two, crew chiefs, who are responsible for the plane’s cargo bay, finding and solving mechanical issues, and acting as gunners on the RMWS. Swift 12’s crew chiefs were a senior sergeant and a corporal, with the senior NCO serving as an instructor for the junior flyer.

As is typical in military accident reports, the report redacts the names of all personnel besides those in the “mishap aircraft.”

The crew chiefs stay connected to the pilots on the plane’s intercom system, serving as the pilots’ eyes for the rear of the plane.

Once on the gun range at El Centro, the Ospreys would make a series of passes over a target — the hulk of an old car — at about 200 feet. The two crew chiefs planned to fire 100 rounds on every pass, one Marine on the trigger, the second feeding ammo, and then strapping down the empty ammo so it wouldn’t float away as the pilots twisted the Osprey around at 30 degrees for the next run at the target.

After six ammo cans, the two Marines would switch positions.

U.S. Marine Corps Sgt. Daniel Pacheco, left, and Cpl. Jared Arnold, right, crew chiefs with Marine Medium Tiltrotor Squadron 265, Marine Aircraft Group 36, 1st Marine Aircraft Wing, fire an M240D machine gun from the back of an MV-22B Osprey aircraft, during a tail gunnery certification in support of Weapons and Tactics Instructor (WTI) course 1-21 in Yuma, Arizona, Oct. 6, 2020. The WTI course is a seven-week training event hosted by Marine Aviation Weapons and Tactics Squadron One, providing standardized advanced tactical training and certification of unit instructor qualifications to support Marine aviation training and readiness, and assists in developing and employing aviation weapons and tactics. (U.S. Marine Corps photo by Cpl. KarlHendrix Aliten)
Two Marine crew chiefs fire an M240D machine gun from the back of an MV-22B Osprey aircraft, during a tail gunnery certification in 2020. (Cpl. Karl Hendrix Aliten/U.S. Marine Corps).

The scene was identical just behind them on Swift 11, where five Marines — two pilots and three crew chiefs — ran through the same training, flying just off Swift 12’s wing, a routine formation for Ospreys during gunnery and general flight. Each time through the range, a pilot on Swift 11 would call Swift 12 to confirm they were about to start shooting: “In hot.”

The weather was good, the aircraft were healthy and the flying was fun.

On the fourth pass, Swift 12’s crew heard the pilot on Swift 11 call over the radio that the second plane would be pulling out of the next pass and climbing to cooler air to bring down the temperature on one of their engine’s gearboxes. 

A “hot box,” the Marines called it, was a routine mechanical issue. It had already happened once during the flight.

Rather than hearing “in hot,” the pilot of Swift 11 radioed that they were pulling up: “Swift 12, detaching.”

It was a routine training moment, not worth a second thought to the crew of Swift 12.

A few seconds later, at 7 seconds past 12:14 in the afternoon, a radar system miles away known as the El Centro Airport Surveillance Radar recorded Swift 11 climbing through 500 feet at 95 knots. On the radar’s next sweep, the blip was gone.

Swift 12 continued its next pass, the senior Marine firing and then putting the RMWS on safe. But as he worked the gun, the sergeant’s peripheral vision perked up: there was a column of smoke beyond the target that wasn’t there seconds before.

“Hey, there’s fire at the five [o’clock],” the Marine called into the plane’s intercom. “Looks like oil or tire fire.” But fires happen on shooting ranges, no cause for immediate alarm. The junior crew chief working the ammunition spotted the smoke and told the pilots to look out the left side as they turned back. 

“You’ll see it when we turn around,” he said. As the plane banked, the pilots spotted the smoke. 

“Yeah, that’s pretty big,” one pilot said.

A cold realization swept over the crew.

“Would it be crazy to call -2?” one asked over the intercom, using the shorthand “dash-two” for their wingman.

“That wouldn’t be crazy at all,” a pilot replied. The senior pilot declared a cease-fire for the training event as the crew began radio calls to their wingman, hoping a voice would respond. Two calls received no response. Swift 11’s image had also disappeared from a radar screen. 

“Well, this isn’t a good feeling at all,” the junior Marine said.

A search for survivors

Seconds later, the Osprey was over the fire’s smoke column, which one pilot later said was already 500 to 700 feet in the air. Around it was unmistakable debris, including the long, thin propeller blades of an Osprey’s rotors. The senior pilot broke the silence on the intercom.

“Yeah, that’s them.”

It had happened so fast, the Marines on Swift 12 later told investigators, with perhaps 30 seconds between Swift 11’s final “detaching” call to the realization that the burning fire was all that remained of the Osprey.

The pilot would later tell investigators his first instinct was to trace his eyes upwind of the crash. Aviators train to move upwind from a crash, out of toxic smoke. But there was no movement.

With that, he knew, it was time for another radio call, this one on an emergency frequency: “MAYDAY.”

For the next hour, the crew of Swift 12 flew overhead as the on-scene commander, first directing rescue efforts and then, when it was clear there were no survivors, securing the scene for the investigation to come.

Helicopters photo
The crash site from above. Pilots responding to the crash instantly knew it was an Osprey crash from the remains of the 3-propeller rotor. (USMC command investigation final report photo).

A mechanical issue kept Swift 12 from landing but a flight of Marine CH-53 helicopters doing unrelated training nearby quickly arrived and set down about 100 yards from the fire. Crewmembers ran to the burning Osprey with fire extinguishers. But within minutes, the Marines found the remains of four of the five crew members and no sign that the fifth Marine might still be alive. 

Later, a Navy MH-60 helicopter arrived and asked if they should also land with more extinguishers, but the crew on the ground waved them off. Any further effort, one told investigators, would have been “fruitless.”

Throughout the search, the senior pilot and crew of Swift 12 acted as the on-scene commander, relaying information to emergency and range officials, advising their unit’s leadership at Pendleton on the crash, and ensuring that aircraft responding to help stayed clear of each other and did not disturb the crash site. It was important to preserve both for the investigation to come and because, they knew, it held the remains of their friends.

The most senior pilot to respond to the crash site was the Navy Lieutenant at the controls of the MH-60, flying under the callsign Landslide 05, from Naval Air Station North Island in San Diego. The pilot had 16 years in the Navy including seven as a pilot with 1,400 flight hours. As the search continued, and the reality of the crash set in, he kept hearing the voice of Swift 12’s pilot.

“Swift was above us in the overhead by at least 500 feet or so,” the Navy pilot said. “The aircraft commander was very calm and in control. I didn’t know how he was doing it.”

Low on fuel, Swift 12 eventually turned toward home. In the back of the plane, the senior Marine told the junior to write down everything he could think of about the day. He wanted to keep the kid busy, he later told investigators.

But the young Marine understood the moment he was in.

“The flight back was super quiet,” he wrote in his final statement. “I was very quiet because I was really close with those crew chiefs. The pilots were doing their jobs, talking to [air traffic control] to get us back safely. I remember thinking, ‘These guys are acting way too fine right now.’ But in hindsight, they were just being good pilots and professionals, making sure we got home safe.”

The latest on Task & Purpose