TAYLORSVILLE, KY, USA
N50AP
Hughes 369D
The flight instructor and commercial pilot were practicing autorotations. On the fourth maneuver, the flight instructor was demonstrating an autorotation that would terminate with a full touchdown. The flight instructor reported that he began the maneuver at 800 feet agl, and initiated the deceleration about 50 feet agl. About 10-15 feet agl, he leveled the helicopter and began the descent to touchdown. When collective was to be applied, the pilot felt a forward pressure on the cyclic, and a tendency for the helicopter to nose down. He reacted by centering the cyclic. When the collective reached 50 percent of travel, the pilot realized that the rate of descent was greater than normal. He applied more collective and advanced the throttle in an attempt minimize the rate of descent, but landed hard in a tail low attitude. The accident was videotaped by a witness. Review of the videotape revealed that the helicopter appeared to stop its descent about 20-25 feet agl and assume a tail low attitude. The helicopter descended, landed on the tailskid, then the aft portion of the main landing gear skids. When the tailskid contacted the ground, the tail boom fractured. The tail assembly was then struck by a main rotor blade, and the helicopter rocked forward on the main landing gear skids, and the left strut failed. Examination of the helicopter revealed there were no mechanical deficiencies.
On April 29, 2001, at 1900 eastern daylight time, a Hughes 369D helicopter, N50AP, was substantially damaged during a practice autorotation to a field in Taylorsville, Kentucky. The certificated flight instructor and commercial pilot sustained minor injuries. Visual meteorological conditions prevailed and no flight plan was filed for the instructional flight conducted under 14 CFR Part 91. The helicopter was operated by the Jefferson County Police Department (JCPD) whose headquarters were located in Louisville, Kentucky. The purpose of the flight was to prepare the commercial pilot for a flight instructor check-ride, which was scheduled the following day. In a written statement, the flight instructor said that he arrived at the JCPD Heliport at approximately 1830, and after a brief discussion with the unit commander, unit instructor, and the pilot, he began the evening's training mission. He further stated: "The aircraft was preflighted by [pilot]. [Pilot] and I conducted a brief pre-flight brief. [Pilot] made the initial take-off. After a brief flight southbound I assumed the duties of flying pilot in order to re-establish currency. I conducted some in-flight maneuvers, such as steep turns, then located a large field in order to practice approach landings. The field was surveyed, both high and low, for suitability. The first two approaches were normal and uneventful. The third approach was a standard autorotation with power recovery. It was normal and uneventful." "The fourth approach was again a standard autorotation however, this approach was planned to terminate with a full touchdown. The initial stages of the maneuver thru deceleration were normal. As the aircraft descended thru approximately 10 feet agl, I began the final phase of the maneuver by leveling the aircraft followed by increasing collective to land. As the aircraft neared the ground it seemed that there was insufficient rotor RPM to cushion the landing and that the aircraft pitched slightly forward. I corrected to attitude and used the remaining RPM to arrest the rate of descent." "The aircraft impacted with higher than normal rate of descent and slid forward approximately 6-8 feet. The emergency fuel shutoff was pulled and [pilot] and I exited the aircraft." A Federal Aviation Administration (FAA) inspector interviewed the flight instructor over the telephone. According to the inspector's record of conversation, the flight instructor stated that he began the autorotation at 800 feet agl, and the deceleration about 50 feet agl. About 10-15 feet agl, he leveled the helicopter and began the descent to touchdown. When collective was to be applied, he felt a forward pressure on the cyclic, and a tendency for the helicopter to nose down. He reacted by centering the cyclic. When the collective reached 50 percent of travel, he realized the rate of descent was greater than normal. He applied more collective and advanced the throttle in an attempt minimize the rate of descent, but landed hard in a tail low attitude. In a written statement, the commercial pilot said he met with the flight instructor, an FAA designated pilot examiner, for an instructional flight in preparation for an instructor's check-ride scheduled the following day. After he pre-flighted the helicopter, they departed to the southeast to practice maneuvers. Shortly after lift-off, the commercial pilot stated that the flight instructor took the controls and began instructing. The commercial pilot said: "In the area of Spencer County we identified a field that was appropriate for the type of maneuvers to be performed. We made an initial approach to look for obstacles and power lines, when we were satisfied that the area was secure we made an approach to the field and made a normal landing to check for firmness of the ground. We then lifted off and made another approach into the field, and a second landing. On the third approach we did an autorotation into the field, recovering with power to a hover. We then lifted-off for another approach, this one to be a full autorotation touchdown." "We approached the field from an altitude of about 800 feet above ground level, set up for a straight in approach. [Instructor] cut the power to ground idle and set up the autorotative approach. As we neared the ground, [instructor] flared the helicopter. At this point we were about 10-15 feet off the ground. [Instructor] then put the helicopter in a flat attitude in preparation for landing, we are now 8-10 feet off the ground. As we were preparing to settle to the ground the helicopter seemed to lose power and drop rapidly, striking hard in the field. The tail boom was torn off in the collision with the ground. The left main skid collapsed and the main rotors struck the ground. We were able to shut off the engine and when the rotors stopped we exited the aircraft. Neither occupant of the helicopter was injured." A witness, who videotaped the helicopter as it maneuvered over the area, was interviewed over the telephone by an FAA inspector. According to the inspector's record of conversation: "[The witness] saw [the helicopter] make two approaches to the field, and he thought they looked normal. Both approaches ended with the helicopter hovering. On the third approach, he thought it looked faster, or hotter, than the others. When the helicopter got near the ground, it leveled off, and then hit the ground. It seemed like it had dropped suddenly from a height of about seven to eight feet. When it hit the ground, parts started flying off." Review of the witness's videotape revealed that the helicopter appeared to stop its descent about 20-25 feet above the ground. Once level, the helicopter gradually assumed a tail low attitude and the rate of descent increased, with little forward movement. The main rotor blades appeared to cone, which increased until touchdown. The helicopter continued to descend to the ground in a tail low attitude, and landed on the tail skid, followed by the aft portion of the main landing gear skids. As the tail skid contacted the ground, the tail boom fractured at the point where the tail rotor gear box was attached. The tail assembly was then struck by a main rotor blade, and the helicopter rocked forward on the main landing gear skids, and the left forward strut failed. One of the bent rotor blades struck the cowling behind the swash plate and above the fuselage, and removed it from the helicopter. An FAA inspector performed an on-scene examination. According to the inspector, one main rotor blade departed the helicopter, and the other blades were bent and folded. After the landing, the helicopter slid about 10 feet, yawed left about 47 degrees, and came to rest in a nose low, left side low attitude. The flight instructor held an air transport pilot certificate with ratings for airplane single and multi-engine land, helicopter, glider, instrument airplane and helicopter. He also held a flight instructor certificate for airplane single and multi-engine land, helicopter, glider, and instrument airplane and helicopter. He reported a total of 10,710 flight hours, of which 1,800 total hours in helicopters, and 650 hours were in make and model. He was also an FAA designated pilot examiner. Additionally, the flight instructor reported that he had last conducted touchdown autorotations in a HU-369 helicopter on March 25, 2000. Winds at Bowman Field (LOU), Louisville, Kentucky, at 1853, were reported from 080 degrees at 5 knots.
the flight instructor's inadequate aircraft control during a practice autorotation which resulted in a hard landing.
Source: NTSB Aviation Accident Database
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