ATHENS, GA, USA
N992CH
Hughes OH-6A
Three helicopters departed in the following order, UH-1, AH-1, and the OH-6A, en route for a static display at an airshow. When the three helicopters neared the destination airport, the pilot of the UH-1 contacted the tower about 6 to 7 miles out and received landing instructions for the group. About 1 mile south of the field on a downwind for runway 09-27, the tower instructed all three helicopters to turn left [north] for an approach to the grass infield south of runway 09-27 then to cross and land in the area north of runway 09-27 and adjacent to the aircraft parking area. Each aircraft turned to a northerly heading for the approach. The pilots reported that they maintained approximately 150-250 feet separation from the aircraft in front. The UH-1 followed by the AH-1 landed uneventfully ahead of the OH-6A. The pilot of the OH-6A slowed the helicopter to 30 knots and reduced the pitch. He stated that when he '...increased the collective to maintain a normal approach profile...the increased collective had no apparent effect. He increased the collective again to arrest the increasing rate of decent. Again, the increased collective had no effect.' As he passed through about 50 feet agl, he noted that the Engine/Rotor RPM had 'dropped below 100 percent.' He announced, 'I have a loss of power,' and rotated the throttle to flight idle and initiated collective pitch pulled at 5 feet prior to touchdown. The pilot/passenger in the left seat stated, '...as we approached for landing, the AH-1 abruptly slowed. We closed within 75-100 feet behind...the AH-1, and [the pilot] raised the aircraft nose to maintain separation...and off set to its' right [east] 75 to 100 feet...[the pilot] called out that the aircraft was settling and he had no power response. He increased collective pitch but the aircraft did not respond and settled vertically...I noticed no warning lights but, as the aircraft hit the ground, I saw the transmission oil pressure light come on. No other warning light came on.' The helicopter slid about 50 feet before it came to a rest upright, and the pilot announced over the intercom that 'he could not shut the engine down' so the pilot/passenger pulled the fuel shut off valve, turned off the switches, and turned the battery off. According to the FAA inspector's statement, '...based on the relatively low time and experience of the pilot and crew member who were in control of this aircraft at the time of the accident...the accident occurred as the result of the pilot's loss of control of the aircraft when he inadvertently flew it into the wake turbulence of the two larger helicopters which landed in front of him...the pilot was unable to maneuver the aircraft out of trouble and consequently, the aircraft settled under power to a very hard landing.' The engine was test run and no discrepancies were found. No discrepancies were found with the airframe or controls. The reported wind conditions at the airport at 1053 were from 270 degrees at 7 knots. This wind condition had set up a crosswind condition from west to east, or from the landing helicopter's left to right. The pilot's flight times on the NTSB 6120.1/2, showed he had a total flight time in all aircraft of 5,100 plus hours, 3,253 hour in helicopters, and a total of 13.9 hour in this make and model helicopter.
On April 16, 2000, about 1115 eastern daylight time, a Hughes OH-6A helicopter, N992CH, owned by Vanderwall Aircraft Inc., and operated by the Army Aviation Heritage Foundation, impacted with the ground while landing at the Athens/Ben Epps Airport (AHN), Athens, Georgia. Visual meteorological conditions prevailed at the time, and no flight plan was filed for the 14 CFR Part 91 positioning flight. The helicopter was substantially damaged. The commercial-rated pilot and commercial-rated pilot/passenger reported no injuries. The flight had departed Hampton, Georgia, about 1040. Four aircraft: a CV-2 (fixed wing), UH-1 (helicopter), AH-1 (helicopter), and the accident aircraft an OH-6A (helicopter), were to fly to Athens, to appear as a static display at an air show. All four pilots were to depart within 10 minutes of each other. The CV-2 departed by itself and the three helicopters departed in the following order, UH-1, AH-1, and the OH-6A. According to the narrative history of flight on the NTSB Form 6120.1/2, Pilot/Operator report, "...the four crews communicated with each other by radio while en route...the CV-2 arrived...first and its crew was waiting on the tarmac...the three rotary wing aircraft neared the...airport...[and] the pilot of the UH-1 contacted Athens tower about 6 to 7 miles out and received landing instructions for the group...about 1 mile south of the field on a downwind for runway 09-27, the tower instructed all three aircraft to turn left [north] for an approach to the grass infield south of runway 09-27 then to cross and land in the area north of runway 09-27 and adjacent to the aircraft parking area. Each aircraft turned...to a northerly heading for the approach. The pilot of two aircraft maintained approximately 150-250 feet separation from the aircraft in front. The UH-1 followed by the AH-1 landed uneventfully ahead of the Boeing-Hughes [OH-6A]...the pilot of the Boeing-Hughes slowed the aircraft to 30 knots and reduced the pitch of the aircraft. He increased the collective to maintain a normal approach profile, but the increased collective had no apparent effect. He increased the collective again to arrest the increasing rate of decent. Again, the increased collective had no effect. As he passed through about 50 feet agl, he quickly scanned the Engine/Rotor RPM and saw that it had dropped below 100 percent. He announced, 'I have a loss of power,' and rotated the throttle to Flight Idle...he established a level pitch attitude and initiated collective pitch pull at 5 feet prior to touchdown. The aircraft touched down in a level attitude with forward momentum. He immediately lowered the collective after touchdown and maintained directional control with anti-torque pedals." The written and supplemental statements of the pilot/passenger, in the left seat stated, "...we were following a UH-1 and an AH-1 for landing...as we approached for landing, the AH-1 abruptly slowed. We closed within 75-100 feet behind...the AH-1, and [the pilot] raised the aircraft nose to maintain separation." The pilot/passenger stated, "...at that point we were approximately 75 to 100 feet behind a TAH-1P Cobra helicopter and off set to its' right [east] 75 to 100 feet." He further stated, "...about 75 to 100 feet altitude while slowing the aircraft for landing, he [the pilot] called out that the aircraft was settling and he had no power response. He increased collective pitch but the aircraft did not respond and settled vertically...I noticed no warning lights but, as the aircraft hit the ground, I saw the transmission oil pressure light come on. No other warning light came on...the aircraft slid about 50 feet before it came to a rest upright...the pilot told me over the intercom that he could not shut the engine down so I pulled the fuel shut off valve, turned off the switches, and turned the battery off...." The FAA examined the wreckage after the crash and according to the inspector's statement, "...inspections did not reveal anything remarkable." The engine was test run at Rolls-Royce/Allison Corporation's facility, Indianapolis, Indiana, on May 19, 2000. The FAA inspector stated, "...the results from the engine run did not reveal any data that suggested that the engine ever performed any less [then] normal throughout it's full range of power...[and] that this office concurs with the findings of both the engine and airframe manufacture's that no mechanical faults contributed to...this accident." According to the FAA inspector's statement, "...based on the relatively low time and experience of the pilot and crew member who were in control of this aircraft at the time of the accident, it is the opinion of this office that the accident occurred as the result of the pilot's loss of control of the aircraft when he inadvertently flew it into the wake turbulence of the two larger helicopters which landed in front of him...the pilot was unable to maneuver the aircraft out of trouble and consequently, the aircraft settled under power to a very hard landing." The reported wind conditions at the airport at 1053 were from 270 degrees at 7 knots. This wind condition had set up a crosswind condition from west to east, or from the landing helicopter's left to right. The pilot's flight times on the NTSB 6120.1/2, showed he had a total flight time in all aircraft of 5,100 plus hours, 3,253 hour in helicopters, and a total of 13.9 hour in this make and model helicopter.
the pilot's failure to maintain control of the helicopter resulting in his misjudging the flare and a subsequent hard landing. Factors in this accident were, the pilot's inadequate planned approach in trail of two heavier helicopters, a crosswind landing which placed the accident aircraft downwind of the rotor wash of the two heavier helicopters, and the pilot's lack of total experience in this make and model helicopter.
Source: NTSB Aviation Accident Database
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