V-22 Faces Mission Capable Rates Issues

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V-22 Faces Mission Capable Rates Issues
May 4, 2009

By Bettina H. Chavanne

It may be flying every mission in theater, but the MV-22 is still facing reliability issues due to inaccurate predictive modeling, according to Lt. Gen. George Trautman, U.S. Marine Corps deputy commandant for aviation.

“We’re working on it, but that’s one concern I have in the Osprey program,” Trautman told Aerospace DAILY April 30. Reliability and maintainability are “not meeting my full expectations yet.”

The V-22 was sent into combat “sooner than we should have,” Trautman said. Typically, an aircraft is deployed only after its has passed its Material Support date, which the Osprey did Oct. 1, 2008. The first squadron was deployed a year prior, in October 2007. That early deployment had an effect on the way the Marine Corps purchased spare parts for the aircraft.

With 55,000 flight hours on the V-22, it has become evident that early predictions of mean time between failures on certain parts were inaccurate. “If [mean time between failures] is worse on the kinds of spares that have a long lead time, you start getting into a problem of how you dig out of that hole,” Trautman said. The goal then is sparing models based on reality, not predictions. “We’re struggling with that a bit,” he said.

The Marine Corps has told Bell Boeing that by 60,000 flight hours, the service would like to achieve 80 percent mission capable rates. Trautman is pleased with the company’s response. “The good news is they’re standing behind the product, they’re engaged,” he said.

Sustained shipboard deployment of the V-22 also has posed a slight challenge to the service. It was discovered that on smaller deck amphibious ships, heat from the downward-pointing nacelles could potentially warp the stringers underneath the deck plates. “We’re concerned with heat on the LPD and LSD decks because the steel is so thin,” Trautman said, adding that the service has “worked through that challenge.”

One solution is to tilt the nacelles forward slightly, which gives 35 minutes of operational time on deck.

The other option is deck plates that provide protection up to 90 minutes. The Marine Corps is working with the Defense Advanced Research Projects Agency and the Office of Naval Research to find coatings for the deck, particularly in light of the F-35 Joint Strike Fighter (JSF). The exhaust from the JSF’s auxiliary power unit has the potential to cause similar heating problems, so the joint program office is working on the issue now, Trautman said.

Source
http://www.aviationweek.com/aw/generic/story_generic.jsp?channel=aerospacedaily&id=news/V22-050409.xml&headline=V-22%20Faces%20Mission%20Capable%20Rates%20Issues