Operations with the Bell Boeing V-22 Osprey tiltrotor are continuing normally as the disintegration of a nacelle cooling fan, which caused an emergency shutdown during recent at-sea testing, is investigated.

Phase IV of the Osprey's shipboard suitability testing was completed successfully, despite ending a day early when one of the two V-22s experienced the nacelle blower failure while hovering over the flightdeck of the assault ship USS Iwo Jima. The aircraft landed normally. The failed component was a fan at the rear of the nacelle used to blow air on to the tilt-axis gearbox to cool the lubricating oil. The US Navy has decided it was an isolated incident.

Preliminary results from the fifth of six planned at-sea periods in the V-22 programme indicate that reprogramming of the digital flight-control system has eliminated the "uncommanded roll on deck" phenomenon - a tendency to tilt sideways when sitting on the flightdeck behind a hovering aircraft.

Source: Flight International