20000508036159A

(-23) On may 8, 2000 at approx. 9:25 am PDT, a Mcdonnell Douglas 520N helicopter, N955SD, sustained substantial damage while performing off-airport training in east Los Angeles, CA. The helicopter was being operated by the Los Angeles county sheriff's dept. As a public-use aircraft under FAR part 91. The commercially rated flight instructor and commercially rated pilot trainee were not injured. The local area instructional flight originated at the sheriff's main base at the long beach airport in long beach, CA. Visual meteorological conditions prevailed and no flight plan was filed. The flight instructor reported that the purpose of the flight was to practice emergency procedures as part of routine interdepartmental training. They were conducting training in an open field on property owned by the sheriff's dept. The flight instructor stated that they often utilized the field for flight training (off-airport operations) and had used the same field one week earlier. He reported that they performed a high reconnaissance of the landing area prior to the landing. He noted nothing unusual about the terrain below nor did he notice anything unsuitable about the landing area. The flight instructor stated that he simulated an engine failure (by rolling off the throttle) at approx. 10-15 feet above the landing area. The pilot trainee, who was on the controls at the time, responded and performed an autorotative landing. The aircraft touched down with forward speed which caused the helicopter to slide a few feet, then stop abruptly. Tall weeds and ground covered had prevented the helicopter from sliding forward with the resulting momentum causing the helicopter to stop abruptly and pitch forward. As the helicopter pitched forward, the instructor pilot positioned the cyclic control rearward. When the helicopter settled back to a level attitude, the main rotor blades flexed down as a result of decreasing RPM and cut off the tailboom. The flight instructor reported that neither of the two pilots had seen the high vegetation in the landing area even though they had made smilar landing in the same area before. End. (.4) on may 8, 2000, at 0925 hours pacific daylight time, a Mcdonnell Douglas 500N helicopter, N955SD, sustained substantial damage while performing off-airport landing training in Los Angeles, California. The helicopter was being operated by the Los Angeles county sheriff's department as a public-use aircraft under the provisions of 14 CFR part 91. The commercial rated flight instructor and commercial rated pilot trainee were not injured. The local area instructional flight originated at the long beach, California, airport, about 0830. Visual meteorological conditions prevailed and no flight plan was filed. The flight instructor reported that the purpose of the flight was to practice emergency procedures as part of routine intradepartmental training. They were conducting the training in an open field on property owned by the sheriff's department. The flight instructor stated that they often utilized the field for flight training purposes, and reported that he had done some training there about 1 week prior to the accident. He reported that they performed a high reconnaissance of the field prior to landing; at that time he noted nothing unsuitable about the terrain. The flight instructor stated about 10 to 12 feet above ground level (AGL), he reduced the throttle to ground idle to simulate a total power loss. The pilot trainee was on the controls; he landed the helicopter with no problems. The flight instructor stated that the helicopter slid forward only a few feet, then stopped abruptly. The skids had become entangled in 18-inch-tall grass and imbedded vines, causing unexpected friction. He stated that the natural tendency to input aft cyclic to stop the aircraft from going over caused the main rotor blades to contact the tail boom. The flight instructor reported that neither he nor the pilot trainee had seen the high vegetation before landing, nor had they ever noted it there in the field before.