Manufacturing lines for two Boeing rotorcraft models remain halted today while officials continue to investigate a “serious” quality breach.

The US Defense Contract Management Agency (DCMA) and Boeing launched the investigation on 21 November after finding foreign object debris in a Bell Boeing V-22 Osprey tiltrotor during an inspection.

News reports quoting Republican Joe Sestak, a Philadelphia-based congressman and retired vice admiral, attribute the damage to a plastic cap found in a fuel line.

© US Navy

“We’re still waiting to hear back on the results from the [corrective action review] from DCMA,” says Boeing. “Employees are coming to clean, inspect and examine processes and procedures to minimise the chance of this ever happening again.” The manufacturer's CH-47 Chinook line is also affected by the action.

Boeing was also forced to shut down production for several days in May after damage was found on two CH-47Fs. A Boeing factory worker was arrested after admitting to maliciously severing a bundle of electrical wires in one aircraft. The source of the damage to another helicopter found vandalised the same day was never identified.

For more V-22 news and images, see Flight's aircraft profile