Flight operations for three models of Marine Corps aircraft were suspended temporarily by the Naval Aviation Systems Command this weekend after officials discovered unrelated problems with each type of aircraft.
The suspension orders were issued late Friday, Aug. 25, for the CH-53E Super Stallion transport helicopter, AH-1W Cobra attack helicopter and the MV-22 Osprey tiltrotor aircraft. A portion of the Corps' AV-8B Harrier jet fleet remains grounded, following a July 11 order suspending flights due to concerns about engine bearing problems.
Most significant is the grounding of 165 of the Corps' heavy-lift CH-53E helicopters, eight of which are currently deployed. The decision to suspend operations is based on the preliminary findings of the crash of a Navy MH-53E mine-sweeping helicopter off the coast of Corpus Christi, Texas, Aug. 10.
Officials suspended AH-1W Cobra flight operations after it was discovered this week that some older rotor blades may be susceptible to cracking. Each of the Corps' 198 helicopters will undergo a one-time inspection to identify and replace, if necessary, the suspect blades before being returned to flight status. Eight of the Cobras are currently deployed.
Officials also suspended flight operations for the MV-22 tiltrotor aircraft after one of the Corps' 11 Ospreys made a precautionary landing Thursday at Camp Lejeune, N.C. The MV-22's backup systems worked flawlessly and the pilot landed safely, but a subsequent maintenance inspection revealed that a coupling on the aircraft's interconnect drive shaft failed.
The coupling was repaired, and the aircraft later returned to Marine Corps Air Station, New River, N.C., where it is based.
Engineers will examine the other 10 MV-22s to ensure the failure was isolated. The Osprey, which can fly like a plane and take off and land like a helicopter, completed operational evaluation in July and is awaiting the go-ahead to proceed with full-rate production. The Osprey is planned to replace the Corps' aging fleet of CH-46 and CH-53D model helicopters.
Meanwhile, the Marine Corps continues efforts to inspect and test all of its F402-RR-408A/B engines for the AV-8B Harrier jet before returning the aircraft to flying status. Since July 11, about 30 of the Corps' 106 Harriers powered by that engine have returned to flying status. About 10 other engines have been inspected and await installation. The remaining engines are due to undergo vibration-scan testing and, if necessary, be repaired before returning to service.