A hard clutch engagement involves the clutch connecting the rotor gear box to the engine slipping, then catching hard, causing the aircraft to lurch.
As part of a safety stand down, on Aug. 16, 2022 the US Air Force Special Operations Command (AFSOC) grounded its CV-22 Osprey fleet. There is not a timeline set for the aircraft to begin flying again, the command confirmed to Air Force Magazine.
AFSOC spokesperson Lt. Col. Rebecca Heyse explained in an emailed statement that the stand down, ordered by AFSOC commander Lt. Gen. James C. “Jim” Slife, comes after two incidents of “hard clutch engagement” in the past six weeks.
Breaking Defense first reported the news of the stand down.
According to Air Force Magazine, a hard clutch engagement involves the clutch connecting the rotor gear box to the engine slipping, then catching hard, causing the aircraft to lurch.
Heyse said that the two incidents in the past six weeks came after two in the previous five years. Heyse added that thanks to the skill and professionalism of AFSOC Air Commandos who operate the CV-22 no injuries have been reported as a result of the incidents.
Heyse pointed out that since AFSOC hadn’t yet gathered enough engineering data analysis to identify the cause of the issue it’s unknown if it’s mechanical, design, software or some combination of any of those.
No AFSOC CV-22s will fly until a root cause is determined and risk control measures are put in place she said. Heyse added that the goal is to determine a viable long term materiel solution.
She said that since the US Marine Corps and US Navy both operate their own versions of the Osprey, AFSOC has been in contact with Naval Air Systems Command about the issue. Heyse deferred comment on any stand down of those aircraft to the respective services.
AFSOC has more than 50 Ospreys in its fleet, based out of Cannon Air Force Base, N.M., Hurlburt Field, Fla., Kirtland Air Force Base, N.M., RAF Mildenhall, U.K., and Yokota Air Base, Japan.
The CV-22 is the Special Operation Forces variant of the U.S. Marine Corps MV-22 Osprey. The first two test aircraft were delivered to Edwards Air Force Base, California in September 2000. The 58th Special Operations Wing at Kirtland AFB, New Mexico began CV-22 aircrew training with the first two production aircraft in August 2006.
The first operational CV-22 was delivered to Air Force Special Operations Command in January 2007. Initial operational capability was achieved in 2009.
The CV-22 Osprey is a tiltrotor aircraft that combines the vertical takeoff, hover and vertical landing qualities of a helicopter with the long-range, fuel efficiency and speed characteristics of a turboprop aircraft. The mission of the CV-22 is to conduct long-range infiltration, exfiltration and resupply missions for special operations forces.
Photo credit: U.S. Air Force