Longstanding and deadly mechanical problems with the V-22 Osprey have gone unaddressed for years by the joint program office, and it may take a decade to complete recommended fixes, as risks continue to mount, a new pair of oversight reports revealed.

Separate findings from the Government Accountability Office and Naval Air Systems Command.pdf), or NAVAIR, were released Friday. Both reports say the Joint Program Office that oversees the V-22 variants for the Air Force, Marine Corps, and Navy failed to adequately assess and address mounting safety risks, even as service members died.

“Without refining the joint program’s process for identifying, analyzing, and responding to Osprey safety risks, program stakeholders cannot adequately mitigate risks that can contribute to death, injury, or loss of mission capability and resources,” the GAO report read.

One of the challenges the office faces in quickly making safety fixes, the separate NAVAIR report said, is that the three services have different mission sets, priorities, and risk tolerance.

Twenty service members have died in four tiltrotor aircraft crashes since 2022. Two major mechanical problems—a sudden surge in power following a clutch slip, known as a hard clutch engagement, and failures within the Osprey’s proprotor gearbox—were identified as causes in recent deadly crashes. But it will take until 2034 to implement full fixes for the latter issue, according to the Navy’s report.

“The cumulative risk posture of the V-22 platform has been growing since initial fielding,” the NAVAIR report read. “The program actively identified risks; however, due to limitations in material solutions, funding prioritization, and urgency, it has not promptly implemented material and non-material fixes to mitigate existing risks. As a result, risks continue to accumulate.”

NAVAIR Findings

The V-22 Osprey has experienced 12 Class A mishaps within the last four years. Seven of those involved parts failures, the Navy’s probe showed—and the mechanical failures had already been identified as major problems in the past.

“These material risks were identified by the Program Office and included in the NAVAIR System Safety Risk Assessments (SSRA) database, but were not sufficiently mitigated or resolved in a timely manner, which resulted in catastrophic outcomes in 5 of the 12 mishaps as the risks were realized,” the NAVAIR report read.

The V-22 has the highest total number of unresolved catastrophic parts issues, known as systems safety risk assessments, among Navy rotor-wing aircraft, and second among all Navy aircraft: 28. The F-35 has the highest total number. Data included in the report showed that as of 2025, the tiltrotor aircraft has the oldest age of unresolved catastrophic system safety risk assessments across the Navy’s aircraft inventory, with an average of more than 10 years.

By contrast, the average across other aircraft in the Navy’s inventory is six years.

This may be in part because probes into V-22 operations and safety in 2001, 2009, and 2017 “lacked mechanisms for tracking implementation or accountability,” the report states, adding “this lack of follow-through resulted in minimal execution of prior action plans.”

The report highlighted human error and mistakes by aircrew and maintenance personnel as a contributing factor in some mishaps. The investigation found that 81 percent of all the accidents that the Ospreys have had on the ground were due to human error.

The report also said the V-22 “consistently had low readiness levels.” On average, between 2020 and 2024 the aircraft had a low mission-capable rate of just 50 percent for the Navy and the Air Force, and 60 percent for the Marines, meaning the V-22s weren’t ready for their missions at least half the time.

The report’s recommendations are wide-ranging and include increased maintenance inspections, implementing a V-22 mid-life upgrade program, strengthening joint program office reporting, and revaluation, by service, of the military’s required fleet size with “updated mission requirements and flight-hour utilization expectations.”

Despite the scathing findings, Vice Adm. John Dougherty, the NAVAIR commander, said the organization is still committed to flying and improving the aircraft.

“We are continuously evaluating procedural compliance to prevent mishaps as well as strengthening airworthiness controls to establish clear risk thresholds,” Dougherty said in a written statement. “Through ongoing analysis and targeted action, we remain committed to improving the V-22’s performance and safeguarding the warfighters who rely on this platform.”

The command did not respond to questions about what, if any, accountability measures were taken in response to the findings.

GAO Investigation

The GAO’s findings similarly sounded the alarm about the Osprey, with their report showing that serious V-22 mishaps “generally exceeded those of the Departments of the Navy and Air Force fixed-wing and rotary-wing aircraft fleets for fiscal year 2015 through fiscal year 2024.”

The Marine Corps and Air Force variants had the highest rates of the most serious accidents in 2023 and 2024, compared with the average serious accident rate for its V-22 variants for the previous eight years, the GAO report read.

Still, Rebecca Heyse, an Air Force Special Operations Command spokesperson, said the component has “complete confidence in the aircraft and the crews and maintainers that operate and fix them.”

Similar to the NAVAIR report, GAO investigators identified a long history of unresolved maintenance problems. V-22 program officials did not regularly share hazard and accident reporting, aircraft knowledge and emergency procedures, or common maintenance data related to the aircraft among the service branches to promote safety, according to the report.

“GAO found that the median age for 28 unresolved serious and medium system risks was about nine years, and over half (17 of 28) had been unresolved for between six and 14 years,” the report read.

While some problems had been fixed, investigators said, more serious problems with the airframe remain.

“For example, program stakeholders, which include the Osprey Joint Program Office and military services that operate the aircraft, had closed 45 risk assessments at the time of our review, but had not fully responded to 34 known system-related risks related to the potential failure of airframe and engine components,” the GAO report read.

Like the NAVAIR report, the GAO findings pointed to flaws within the V-22’s joint program office. Overall, the GAO recommended the Defense Department refine its process for comprehensively responding to all Osprey safety risks, determine a revised oversight structure, better share safety data, and regularly review and revise its maintenance procedures.

The Mechanical Issues

The investigation lays much of the responsibility for the problems on the Osprey’s Joint Program Office. Part of the mission for this office, which operates within NAVAIR, is making sure the aircraft can be safely flown by the Marine Corps, the Navy and the Air Force, all of which use different versions of the aircraft for different missions.

The report found that this office “did not effectively manage or address identified risks in a timely manner, allowing them to accumulate,” and it faced “challenges” in implementing safety fixes across all three services.

Two major issues involve the Osprey’s complicated transmission. The aircraft has a host of gearboxes and clutches that, like a car’s transmission, are crucial to powering each propeller behind the Osprey’s unique tilting capability. The system also helps connect the two sides of the aircraft to keep it flying in the event of engine failure.

One problem is an issue in which the transmission system essentially shreds itself from the inside due to a power imbalance in the engines. That brought down a Marine Corps Osprey, killing five Marines in California in 2022.

The other issue is a manufacturing defect in the gears within the transmission that renders them more brittle and prone to failure. That was behind the crash of an Air Force Osprey off the coast of Japan in November 2023 that killed eight service members.

The report reveals that this manufacturing issue went back to 2006 but the Osprey’s Joint Program Office did not formally assess or accept this risk until March 2024.

While fixes for both mechanical issues are in the report, it will take until 2034 and 2033 for the military to fully address both issues, respectively. Naval Air Systems Command did not reply when asked if it had a message for troops who will fly in the aircraft in the meantime.

Calls for Accountability

Military families who lost loved ones in V-22 crashes, and lawmakers, have been demanding accountability for the Osprey program since the string of deadly crashes.

The 33-page NAVAIR report was first commissioned in September 2023. The GAO’s report, requested by the House Subcommittee on Readiness, follows outrage from members of Congress earlier this year related to delays in getting key safety data.

Amber Sax’s husband, Marine Corps Capt. John J. Sax, died in a 2022 Osprey crash in California which killed all five Marines aboard. That crash was caused by a hard clutch engagement, a problem the Marine Corps had known about for more than a decade.

“Their findings confirm what we already know: More needs to be done, and more needed to be done,” Sax said in response to the GAO report. “It’s clear in the report that these risks were not properly assessed, and that failure cost my husband his life. I’m grateful these issues are finally being brought forward, but the work can’t stop here. They owe it to our family, and to every person flying in this airframe. These V-22s can carry more than 20 people in the back. That responsibility is enormous, and they need to do better.”

The Future of Vertical Lift

This year, several defense contractors have pitched prototypes for unmanned tiltrotor aircraft to support future military missions that platforms like the Osprey may have taken on.

In October, the prime contractor unveiled its design for its CxR aircraft which seeks to place unmanned vertical-takeoff-and-landing aircraft alongside helicopters in combat and cargo operations. That same month, Sikorsky announced NOMAD, its offering of a rotor blown wing vertical take-off and landing drone.

The Associated Press reported last year that the most serious types of accidents for the Osprey, which is the only aircraft to fly like a plane but convert to land like a helicopter, spiked between 2019 and 2023 and that, unlike other aircraft, the problems did not level off as the years passed.

“As the first and only military tiltrotor aircraft, it remains the most aero-mechanically complex aircraft in service and continues to face unresolved legacy material, safety, and technical challenges,” the report said.