The US Department of Defense (DoD) has halted the operations of an undisclosed number of V-22 Osprey aircraft over safety concerns.
Investigators have found that when the aircraft reaches a certain number of flight hours, its input quill assembly must be replaced to continue operating safely.
The input quill assembly attaches the Osprey’s engine to its prop-rotor gear box, directly affecting its clutch.
A significant increase in hard clutch engagements has reportedly been noted, prompting the DoD to begin conducting an engineering analysis.
“The fleet bulletin identifies aircraft with input quill assemblies above a predetermined flight hour threshold and the requirement to replace that component. Once replaced, aircraft will return to flight status,” the US Marine Corps said in a statement.
The department did not disclose the flight hour limit of the input quill assembly in question or the number of planes affected.
However, it says that the Ospreys with flight hours well below the time limit will continue operating.
Previous Grounding
The V-22 Osprey has previously experienced safety issues.
In August last year, the US Air Force Special Operations Command grounded its own Osprey fleet due to safety incidents involving the clutch.
Two dangerous incidents occurred in a span of six weeks and four since 2017.
The air force only lifted the grounding in early September after the aircraft was declared safe for use.
