IAD00LA039

The pilot hovered the helicopter out of ground effect about 200-300 feet above ground level. While in the hover, the helicopter began a slow turn to the left even with full right anti-torque pedal applied. The pilot was not aware of his rotor RPM or heading when the helicopter began to turn. He attempted to recover by lowering the collective, but continued to lose altitude. The pilot landed on a sloped hillside and the helicopter rolled over on to its right side. On scene examination of the helicopter revealed no mechanical deficiencies. Review of the flight manual's height velocity envelope revealed that the pilot operated in an area where out of ground effect hovers should have been avoided.

On May 6, 2000, at 1010 Eastern Daylight Time, a homebuilt RotorWay Exec 162F, a helicopter, N162RS, was substantially damaged during a forced landing in McMurray, Pennsylvania. The certificated private pilot/owner sustained minor injuries. The local flight originated at the Allegheny County Airport (AGC) about 1000. No flight plan was filed for the personal flight conducted under 14 CFR Part 91. Visual meteorological conditions prevailed.

In a telephone interview, the pilot stated:

"I was hovering out of ground effect approximately 200-300 feet above a friend's home and was looking outside of the helicopter. The helicopter began a slow turn to the left and I realized I was losing tail rotor effectiveness. I had full right pedal, and the helicopter continued to turn to the left. I lowered the collective and attempted to recover, but continued to lose altitude. I then leveled the helicopter, flew it over a clearing, and put it down. I landed on a slope, and the helicopter subsequently rolled on to its right side. I did not see the rotor rpm during the event, and did not hear the low rotor rpm warning buzzer at any time. I do not recall the direction the helicopter was heading prior to it starting its turn to the right."

In a written statement the pilot reported:

"Heading south until clear of the[airport] pattern traffic, I then turned west. I planned to fly over a friend's house that had planned to meet me at the airport, but stayed home instead. The flight to his home was uneventful.

"His house was on my left side (the back side of his house) so I circled to my left coming around the front. Upon coming abreast of his house at approx. 200 feet, I slowed to a hover. I was looking down at he and his family as they looked up at me when the tail of the aircraft started a turn to the right. I stepped on the right pedal until it hit the stop. The tail was still coming around. I lowered the collective to minimize torque. This did not stop the tail from turning."

In a written statement, a witness said:

"I saw the helicopter pass over my yard, make a 180-degree turn, come back over, and slow down. At this point, it was moving back and forth, then turned sideways, while losing altitude. I then lost sight of it, and seconds later I heard it hit the ground."

Two Federal Aviation Administration (FAA) inspectors conducted an on-scene examination on May 6, 2000. According to the inspectors, the helicopter was found to be laying on its right side. Flight control continuity was established and fuel was present in the fuel tank. Damage to the helicopter included damage to the main rotor, tail rotor, right-hand skid, the tail boom and cockpit. The helicopter had accumulated a total time of 15 hours.

An FAA inspector talked to the pilot on scene. According to the inspector's record of conversation:

"[The pilot] was circling his business partners house at 200-300 feet, when he got behind the power curve. He did not know how low the rpm went on the rotor, but when he added power he lost control of the helicopter. The pilot stated that he then cut the power and autorotated to the ground. He stated the accident was caused by pilot error."

FAA Advisory Circular 90-95 stated, "Loss of tail rotor effectiveness (LTE) is a critical, low-speed aerodynamic flight characteristic which can result in an uncommanded rapid yaw rate which does not subside of its own accord and, if not corrected, can result in the loss of aircraft control. LTE is not related to a maintenance malfunction and may occur in varying degrees in all single main rotor helicopters at airspeed less than 30 knots."

Review of the RotorWay Exec 162F flight manual revealed there were no written procedures pertaining to LTE. However, on page 17 of the manual, "out of ground effect (OGE) hovers are prohibited for all Exec pilots under 150 hours."

Review of the flight manual's height velocity envelope revealed the pilot operated in an area where OGE hovers should have been avoided.

When asked how this accident could have been prevented, the pilot reported, "Don't hover out of ground effect."

The pilot reported a total of 446 hours in helicopters of which 25 hours were in make and model. The pilot reported there were no mechanical deficiencies with the helicopter.