19991007028609A

(.19) On October 7, 1999, at 2005 hours pacific daylight time, a Mcdonnell Douglas 369E, helicopter, N991SD, was substantially damaged during an emergency landing at Moreno Valley, California, following an in-flight loss of directional control. The commercial pilot and two passengers were not injured. The helicopter was operated by the riverside county sheriff's department under the provisions of 14 CFR part 91 as a public-use aircraft. Visual meteorological conditions prevailed and no flight plan was filed for the local area patrol flight, which originated from hemet, California, at 1935. According to a sheriff's department spokesman, the aircraft was orbiting the scene of a traffic accident. In accordance with department operating procedures, the pilot had identified a school athletic field as a suitable emergency-landing site. While orbiting, the helicopter began yawing to the right uncontrollably and the pilot, assuming loss of antitorque control, executed an emergency landing approach to the athletic field. The ensuing hard landing severed the tail boom of the helicopter. (-23)the riverside sheriff's heli crashed onto its side, when it made a hard landing at the creekside elementary school in Moreno Valley CA. The pilot was ona routine air patrol overseeing a traffic stop by a ground patrol unit. The pilot was circling the area and began having difficulties controlling the a/c. a decision was made by the pilot to land the heli in a nearby vacant school yard. While orbiting, the heli began yawing to the right uncontrollable and lost directional control. No injuries occurred to the pilot and the two passengers aboard the heli. The heli encountered substantial damage. No pre-impact failures were indicated by theprivacy data omittedchief air safety investigator for the Boeing company. This accident has no maintenance discrepancies and appears to be an operational error. (.4)on October 7, 1999, at 2005 hours pacific daylight time, a Mcdonnell Douglas 369E helicopter, N991SD, was substantially damaged during a forced landing at Moreno Valley, California, following an in-flight loss of directional control. The commercial pilot and two observer crewmembers were not injured. The helicopter was operated by the riverside county sheriff's department under the provisions of 14 CFR part 91 as a public-use aircraft. Visual meteorological conditions prevailed and no flight plan was filed for the local area patrol flight, which originated from hemet, California, at 1950. According to the sheriff's department report, it was a dark night and the winds aloft were northerly at 20 to 25 knots, at 500 feet AGL, as the pilot orbited over ground based law enforcement activity. In accordance with department operating procedures, the pilot had identified a school athletic field as a suitable emergency landing site. He was attempting to shine the helicopter's spotlight on a vehicle; however, the northerly wind kept blowing the aircraft well south of the location on each of the first two orbits. On the third orbit, he inadvertently allowed the helicopter to slow below translational lift speed and the helicopter yawed 180 degrees to the right uncontrollably. The pilot momentarily recovered directional control of the helicopter but then the right yaw resumed. He made several more attempts to recover directional control of the helicopter but when he saw the altitude becoming low, he flew to the pre-selected landing zone where the helicopter landed hard while in a right yawing spin. During the landing the main rotor blades severed the tail boom and the helicopter came to rest on its right side.