It took twenty years and $19 billion. But at 4pm today, I'm told, the Pentagon's Defense Acquisition Board will announce its recommendation to go ahead with "full rate production" of the once star-crossed, accident-prone Osprey V-22 tiltrotor craft.The fate of the hybrid aircraft has been very much in question, ever since a pair of Ospreys crashed in 2000, killing 23. This decision "gets the program off probation. It can't be summarily cancelled now," a source close to the program says.It's not exactly clear how many of the hybrid aircraft will eventually be manufactured. The President proposed budget calls for 458 Ospreys to be built into the next decade, starting with 13 next fiscal year. The Marines are ultimately scheduled to get 360 aircraft, Special Operations Command are supposed to have 50, and the Navy is slated to have 48. "Pentagon budget documents show the cost of V-22s at about $100 million each," the Star-Telegram notes. Osprey makers Bell Helicopter say the figure is more like "$72 million and headed down."Those prices and those plans could change in the years to come, of course. But this much is set: A squadron of pilots starts training on the V-22 next week. And an operational squadron of nine Ospreys will be ready to fly out of North Carolina's Marine Corps Air Station New River by 2007.THERE'S MORE: Inside Defense has the report from the Pentagon's testing office, which gave the thumbs-up to the V-22.AND MORE: The watchdogs at the Project on Government Oversight still aren't convinced. "It cant autorotate to a safe landing, has no defensive gun, lacks the ability to perform quick evasive combat maneuvers under fire, and cant descend too quickly or it will go into a dangerous roll," they say.AND MORE: The Osprey's final two crashes were due to a mysterious aeronautical phenomenon known as "vortex ring state." after re-reading Wired's Osprey story, I can't say I feel too good about how that's been dealt with.
Lead test pilot Tom MacDonald of Boeing was assigned the VRS problem. "It was this mystery area," he says. "So little research had been done on it. People wondered: Would it swallow planes alive?"MacDonald and the engineers worked out a system. He'd take the plane to 10,000 feet, putting enough air between him and the ground so he'd be able to recover if he got into trouble. Then he'd pull the nacelles back until they were almost vertical, in helicopter conformation, slow his forward airspeed, and try to induce VRS."We'd fly all day long," says Gross, copilot on a few of the test runs. "We'd fall 2,000 or 3,000 feet and recover. We'd fly back up to 10,000 feet, repeat the exercise at 1,000 feet per minute, then 1,500, then 2,000, all the way up to 5,000 feet per minute. Then we'd do it again, this time changing our airspeed." (A typical rate of descent for a 747 passenger jet on runway approach is 700 to 800 feet per minute.) In the process MacDonald, a former Marine pilot, quadrupled the published knowledge base on VRS.What he found was that vortex ring state is surprisingly hard to induce. He had to fly slower than 40 knots while keeping the plane in a steady position for at least five seconds, and then descend at a hot 2,200 feet per minute. He also found that in an Osprey, he could recover from the condition relatively easily, provided he had 2,000 feet of altitude to play with. In the end, the team didn't alter the aircraft. Solution: Install a simple warning system. When a pilot pushes an Osprey toward VRS, a light flashes in the cockpit and a voice cautions, "Sink rate." And Osprey pilots now know to pay attention to those warnings.