The US Marine Corps is investigating the cause of an engine fire that forced a Bell Boeing MV-22 to make an emergency landing in North Carolina on November 6.
The Block A aircraft is understood to have suffered severe damage, although no one was injured. The incident occurred around 9 pm near the MV-22 training squadron’s home base at Marine Corps Air Station New River.
The USMC has deployed 10 MV-22s to Al Asad Air Base, Iraq, and the US Air Force is keen to quickly deploy its handful of CV-22s as well.
The circumstances of the incident raise three possibilities for the cause: human or maintenance error, a recurring problem with the engine air particle separator (EAPS), or yet a new mechanical or design flaw that had gone undetected through development and operational testing.
The original EAPS unit has been linked to two engine fires since December. In the first incident, a hydraulic line ruptured due to a faulty bearing inside the EAPS housing within the nacelle. The second engine fire in April was traced to a maintenance error that triggered a similar problem.
The USMC responded to that incident by creating a modification kit for the EAPS unit, which was installed on each of the MV-22 Block Bs that deployed to Iraq.
The Block A aircraft involved in the latest incident was not equipped with the modification kit.
The V-22 programme endured four fatal crashes in development, prompting the Block A redesign to address concerns about hydraulic line chafing and susceptibility to the vortex-ring state phenomenon.