Rotorcraft Update: Tltrotor flight-test proceeding satisfactorily

 - May 9, 2008, 6:52 AM

A pair of Bell Boeing MV-22 tiltrotor transports have joined the remedial developmental flight-test program that’s hoped to get the cause of tiltrotor operations back on track following a series of fatal accidents and scandalous revelations concerning performance coverups by high-ranking Marine officers. The two new aircraft are part of a gradual ramp-up to a total of seven Ospreys serving the flight-test program now under way at the U.S. Navy’s Naval Air Systems Command in Patuxent River, Md. Since October, the first MV-22 fitted with the post-investigation improvements to hydraulics and flight-control software has been flying. The two new tiltrotors–a low-rate initial production (LRIP) MV-22 and a second engineering and manufacturing development (EMD) aircraft–will be used to evaluate different facets of the tiltrotor mission. In the LRIP’s case, that means being instrumented for the aerial delivery of people and cargo in the months ahead and then being used to expand the internal cargo envelope to include parachute delivery of the cargo. The second EMD aircraft is performing high rate of descent (HROD) testing to further expand and more clearly define the boundaries of vortex ring state, a flight regime cited as a contributing factor to at least one of the four mishaps the program has suffered in its nearly 15 years of development. Over a 13-month period, the EMD will accumulate approximately 160 flight hours in HROD testing. Plans call for four more Ospreys to join the integrated test team group. Test flights conducted by the integrated test team surpassed 100 hr on November 8, with no clear limit set on how many will be needed before Pentagon program managers are satisfied.

Meanwhile, back in Arlington, Texas, development work on the civil BA609 tiltrotor is under way. Backburnered last winter in favor of more pressing V-22 issues, the six- to nine-passenger civil tiltrotor prototype is undergoing installation of the instrumentation required for its preliminary engine runup. “Runups should begin at the end of this month,” said a Bell spokesman, “or maybe later. We’re not committing the program to meet this or that deadline or timetable, but instead taking the time that everyone involved with the program needs to get it right.”