20130317004719A

From the limitations section model R22 rotorcraft flight manual: flight when surface winds exceed 25 knots, including gusts, is prohibited unless the pilot manipulating the controls has logged 200 or more flight hours in helicopters, at least 50 of which must be in the rhc model R22 helicopter.

From interviews with the pilots involved: instructional flight for a private pilot who was preparing for commercial pilot check ride, departed prc at 1634 local time. The student pilot had 170 hours of rotorcraft flight time, 140 hours of which was in the R-22. The weather information that the pilots said they had from ATIS and prc tower, included winds at 280 degrees @ 17 gusting to 24. (METAR indicated wind gusts to 27) the student began a pinnacle approach by completing one orbit. At about 300 feet out in the horizontal plane and about 100 feet above the intended termination point (landing zone ?lz?), a downdraft was felt by the pilots and the student increased collective control. The flight instructor believed that the student?s application of the collective control had been too aggressive and advised him as such. About 5 to 10 seconds later, at about 100 feet out in the horizontal plane and about 50 feet above the intended termination point, another downdraft was felt by the pilots and again the student increased collective control. The flight instructor believed that the student?s application of the collective control input was excessively aggressive. The rotor RPM dropped and the low rotor speed warning annunciated. The flight instructor took the controls and initiated low rotor RPM procedures. The aircraft contacted the ground short of the intended termination point on a sloped rocky surface and then immediately rose up while yawing approximately 90-110 degrees to the right. Aircraft control was regained with the helicopter?s left skid contacting the slope, perpendicularly to it. The flight instructor held the aircraft against the slope, ensured that the rotor RPM was in the normal operating range (101-104%), and then flew the helicopter to a suitable landing spot adjacent to the pinnacle. The flight instructor inspected the helicopter and found a crease on the lower right side of the tail boom just aft of its mounting point.

From inspection of the helicopter at the site of the accident: there was a buckling of the tail boom aligned with the lower right attachment bracket and starting at the edge of the doubled for that bracket. The buckling is 6.15 inches long (from the 3:30 position to the 5:30 position), 3.8 inches wide (at the widest point), and 0.885 inches deep (at the deepest point). The right skid was bent vertically in the middle. It was cracked and indented on the underside at the apex of the bend. The arch of the bend was 1 inch at the center and spread over about 4 feet of skid length. The forward inside portion of the left skid had fresh scrape marks.

From inspection of the accident site: there were scraped and overturned rocks where the front of the skids were when the helicopter first contact with the ground. There was a rock with scrape marks on its pointed upper surface where the center of the right skid was when the helicopter first hit the ground. There was disturbed ground where the left, uphill, skid was, when the helicopter contacted the ground the second time.