Fraudulent performance data in V-22 Osprey Flight Manuals?

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Philip, any comment on the 2013 allegations that the official V-22 Osprey flight manual and simulators contain fake, overly optimistic performance data? That guy says they do, and it caused crashes. I'm no pilot, but if that's true, it seems like some very serious corruption to me. Would that be unique, or are there known past cases of fake data in flight manuals?

-- Andrew Piskorski, June 9, 2013


Sorry, Andy, for letting this sit so long. I think generally FAA flight manuals are reasonably accurate in that at least one pilot in one aircraft managed to do whatever the manual says. However, an aircraft that is 5-10 years old and has a tired piston engine probably won't be able to meet the book numbers. For jets the numbers seem to be more accurate. The Osprey is all military so there is minimal oversight compared to civilian stuff.

This web page has some inaccuracies. "If a helicopter lacks the power to hover, it cannot take-off." This is simply not true. A helicopter with skids can slide along the ground until it reaches about 20 knots and then it will have plenty of extra power to take off. For a helicopter with wheels this kind of rolling takeoff is a more or less normal procedure. (That said, taking off when you don't have enough power to hover puts you into an awkward situation if you need to land anywhere other than an airport.)

-- Philip Greenspun, September 28, 2013