The US Department of Defense has allowed Bell Boeing V-22 Osprey test flights to resume, but is setting strict criteria which must be met over the next two years before a decision on full-rate production. Meanwhile, low rate initial production (LRIP) has been further reduced to nine MV-22s for the US Marine Corps, with no US Air Force CV-22s due to budget constraints.
Despite a series of reports that could find no fault with tiltrotor technology, DoD undersecretary for acquisition Pete Aldridge still has "some doubts". He says: "The only way to prove the case one way or the other is to put the aircraft back into flight test. But this new flight test, which will start in April 2002, will be more comprehensive than that previously planned."
The effort will encompass further vortex-ring studies - the phenomena was blamed for the fatal July 2000 MV-22 crash - and shipboard compatibility, including flow conditions with one proprotor over the deck and the other over the sea. Other test parameters include low-speed combat manoeuvring, ground environment effects and formation flying.
Aldridge, in response to questions about his known scepticism about the V-22, replies: "Myconcerns were on the aerodynamic qualities of this aircraft, which has the unusual characteristics that the props are out on a 20ft [6m] lever arm, and the uncertainties of the lift of those things caused control problems with the helicopter. Plus, the fact that that the props are relatively small diameter, so you're putting enormous loads on each."
The recently established US Navy and Industry Joint Programme Office had already laid out a three-phase iterative plan for design modifications to address more immediate safety issues in returning the V-22 to the air by April after more than a year's. Aldridge has given the plan his blessing, but not committed to full production.
Meanwhile, the DoD will fund LRIP purchases - but this year below what Bell Boeing regards as the sustainable annual rate of 12. The USAF has dropped plans to buy two CV-22s this year and will not fund any more until flighttesting has progressed. Any LRIP MV-22s built for the USMC will not be fully completed until design changes are developed.
Source: Flight International
