posted on Jul, 10 2012 @ 07:45 PM
The crash of a Marine V-22 in Morocco in April, that left two dead, and two injured has been put down to "bad flying". The copilot was a qualified,
but inexperienced pilot, with a more experienced aircraft commander. Neither pilot noticed that when they took off, they had a tailwind that came up
unexpectedly, and they tried to drop the nacelles to horizontal flight at low altitude and low airspeed. When they did this, the combination of the
change of CG, and the tailwind pushed the nose down, and they nosed into the ground. Both pilots, being strapped tightly into their seats survived
with serious injuries, while both crew chiefs, who tend to stand in the back, with a strap to hold them in if the door is open, were killed.
Just prior to the accident, with the less experienced but fully trained copilot at the controls, the Osprey had set down helicopter-style to drop
off at least the second load of troops its crew had delivered that day to the same austere landing zone. As the pilots took off to return to a
temporary on-shore base, the following events unfolded in quick succession:
Under a clear, daylight sky and with no dust interfering with the crew's view, the pilot at the controls lifted the Osprey into a hover 20 or 30
feet above the ground with the plane's nose pointing into the wind, as it had been when the aircraft landed a few minutes earlier.
The pilot flying then used his foot pedals to turn the Osprey in a half-circle to the right, rotating in mid-air to head in the direction from
which they'd arrived. As the aircraft turned, it climbed to about 50 feet.
As the Osprey turned, the pilot pitched the aircraft's nose down about 10 degrees by pushing the control stick forward with his right hand. At
the same time, using his left hand, he turned a small thumbwheel on the Osprey's throttle, or Thrust Control Lever, to tilt the nacelles and rotors
down from 90 degrees and brought them to an angle significantly less than 75 degrees – a position that violated flight manual limits on nacelle
angles at low forward airspeed. The effect was to shift the Osprey's center of gravity too far forward, causing the nose to plunge downward.
As the nose went down, the pilot was unable to hold it where he wanted by pulling back on the control stick because the horizontal stabilizer at the
aircraft's tail was being pushed up and forward by a 20-knot tailwind. The tailwind's speed and direction were depicted on a digital map inside the
cockpit, but vegetation in the area was too sparse to alert the pilots to the wind as they looked outside the aircraft during takeoff. The tailwind
pressure on the horizontal stabilizer reduced the stick's "aft control authority" while adding downward leverage on the nose. "By the time the
pilot realized he was out of back stick authority, it was too late," one source observed.