Aviation Accident Summaries

Aviation Accident Summary CHI99LA309

GRAIN VALLEY, MO, USA

Aircraft #1

N787TP

Pinick HORIZON 2

Analysis

The airplane on its maiden flight was seen just above runway 27 at the Grain Valley Airport, Grain Valley, Missouri, heading westbound. One witness said the airplane was flying nose high and wobbling as if it did not have enough speed. The airplane made a sharp left turn and disappeared behind the trees. Another witness said that the airplane was flying in a nose high attitude and did not seem to be gaining any speed. He watched the nose come down slightly as if the pilot was tying to gain speed, but then go back up again. As the airplane neared the west end of the runway, the witness said it turned left or south, and began descending with the nose high and the tail down, until it disappeared behind the trees. Both witnesses went to the accident site and found the airplane engulfed in flames. Examination of the wreckage revealed the adjuster screw on the propeller hub, used for setting the pitch of the blades, was extended 1 42/64 inches above the adjuster plate. The propeller manufacturer stated that the propeller is ground adjustable from 18 inches (feather) to 52 inches, with 35 inches being the neutral setting. The adjuster screw extension for the neutral setting is 1 7/16 inches. A screw measurement of 1 42/64 inches would equate to a propeller blade setting of 27 inches.

Factual Information

On August 25, 1999, at 1652 central daylight time, a Pinick Horizon 2, N787TP, owned and piloted by a private pilot was destroyed when after takeoff from runway 27 (4,507 feet by 44 feet, dry asphalt) at the Grain Valley Airport, Grain Valley, Missouri, the airplane departed controlled flight and impacted the terrain. A post-crash fire ensued. Visual meteorological conditions prevailed at the time of the accident. The personal flight was being conducted under 14 CFR Part 91. No flight plan was on file. The pilot was fatally injured. The local flight was originating at the time of the accident. Witnesses on the ground saw the airplane in the air, just above runway 27, heading westbound. One witness said the airplane was flying nose high and wobbling as if it did not have enough speed. The witness said the airplane made a sharp left turn and disappeared behind the trees. Another witness said that the airplane was flying in a nose high attitude and did not seem to be gaining any speed. He said he watched the nose come down slightly as if the pilot was tying to gain speed, but then it [the nose of the airplane] went right back up. As the airplane neared the west end of the runway, the witness said it turned left or south, and began descending with the nose high and the tail down, until it disappeared behind the trees. Both witnesses went to the accident site and found the airplane engulfed in flames. The airplane was constructed by the pilot from plans, between April, 1994 and June, 1999. The airplane was issued a Special Airworthiness Certificate for experimental category by the Federal Aviation Administration (FAA), on August 19, 1999. The owner of the hangar in which the pilot kept his airplane, said that the airplane had never been flown. An FAA inspector examined the airplane wreckage at the accident site. The accident site was located in a field, 1/4-mile southwest of the Grain Valley Airport. The accident site consisted of a ground scar surrounded by burned grass. The majority of the airplane was located at the ground scar. Several pieces of the airplane fanned out south of the wreckage, 40 feet from the ground scar. The airplane, except for the upper portion of the vertical stabilizer and rudder, was charred and consumed by fire. The engine rested inverted and was charred. Flight control continuity was confirmed. Examination of the propeller hub revealed the turn screw adjustor for adjusting the pitch of the propeller blades was extended above the adjustor plate, approximately 1 42/64 inches. The propeller was a 70-inch, 3-bladed, ground-adjustable model, manufactured by Ivoprop Corporation, of Bellflower, California. According to information provided by the company, the propeller pitch could be adjusted "from 3 to 17 degrees on the tip, or in inches of helix, advancement from 18 inches to 52 inches." A representative of Ivoprop Corporation said that when the adjustor screw is extended 1 7/16 inches above the plate, the propeller blades are at the neutral pitch position. The screw will turn 5 1/2 turns either side of the neutral position to run the blades from 18 inches of pitch (feather) to 52 inches of pitch. Turning the screw so that it is advancing into the plate adjusts the blades toward a flat pitch. Withdrawing the screw adjusts the blades toward feather. The neutral position equates to 35 inches of pitch. This is the blade pitch angle that is recommended for most flights. "If a pilot wanted fast performance in cruise flight, the pilot would set the propeller blades closer to the 52-inch setting. The trade-off, however, is that the airplane will not climb as fast. If the pilot wanted a better climb rate, the pilot would favor a setting less than neutral." In a statement to the FAA, the propeller manufacturer said that a screw measurement of 1 42/64 inches would equate to a propeller blade setting of 27 inches.

Probable Cause and Findings

The pilot's failure to maintain adequate airspeed which resulted in an inadvertent stall. Contributing to the accident was the pilot's lack of experience in this type of airplane.

 

Source: NTSB Aviation Accident Database

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