The US Marine Corps (USMC) has started repair work on its CH-53E Super Stallion heavy lift helicopters to fix system issues.

The decision for full reset of the helicopters follows a crash of an MH-53E Sea Dragon aircraft, US Navy version, in 2014.

A probe into the incident determined that electrical wires inside the aircraft had chafed against and breached a fuel line, sparking a fire that flooded the cabin and cockpit with thick smoke.

"The material condition of the aircraft, both the CH-53E and the MH-53E, was degraded."

Naval Air Systems Command H-53 Heavy Lift Helicopters Programme Office (PMA-261) programme manager colonel Hank Vanderborght said: “What was discovered was that the material condition of the aircraft, both the CH-53E and the MH-53E, was degraded.

“Those helicopters have been around since the early 80s, so 30-plus years, and we had been at war [on terrorism] for the last 15 years, so the machines had been used pretty hard.”

In response to the findings of the Super Stallion independent readiness review (SSIRR), the USMC has adopted a 'two-step strategy', under which the authority will completely reset all 147 aircraft over a period of three years.

USMC aviation deputy commandant lieutenant general Jon Davis said: “We are going to put every airframe through an on-average 110-day process of stripping the aircraft down completely, rebuilding it and changing out any high-time components.”

In April, the reset validation aircraft was completed at Marine Corps Air Station New River, North Carolina, and flew back to the west coast in June.

Currently, the repair work on five CH-53Es is underway at New River and two at Marine Corps Air Station Miramar, California, while 16 more aircraft will be gradually included into the repair plan.

Maintenance crews had already replaced fuel lines and the wire bundles in most of the Super Stallions enhancing the current percentage of ready CH-53Es to 30%.

Image: CH-53E Helicopters to undergo repair work. Photo: courtesy of Naval Air Systems Command.