Accident Details
Probable Cause and Findings
the pilot/builder's improper design change which resulted in a loss of control following an intentional stall. A factor was an erroneous weight-and-balance calculation.
Aircraft Information
Registered Owner (Current)
Analysis
On October 4, 1996, approximately 1730 mountain daylight time, a Young Cozy MK IV, N96PJ, was substantially damaged when it collided with terrain at Pueblo, Colorado. The airline transport-rated pilot was seriously injured. Visual meteorological conditions prevailed, and no flight plan was filed for the personal flight being conducted under Title 14 CFR Part 91. The flight originated at Pueblo, Colorado, on October 4, 1996, at 1704.
According to the pilot, he was practicing slow flight and stalls at 10,000 feet msl (5,000 feet agl). The only thing he could recall was that the "main wing stalled" and that the canard is supposed to stall first. The nose pitched up and he was unable to break the stall.
An examination of the wreckage at the pilot's Pueblo, Colorado, residence by an FAA airworthiness inspector, the airplane's designer, and an NTSB student intern on November 14, 1996, revealed the following: (1) Data supplied by the pilot on the elevator position he had to maintain in cruise flight indicates he used too low an angle of incidence on the canard wing. This would allow the airplane to attain too high an angle of attack. (2) Three of the 6 required vortilons (used to restrict spanwise air flow and prevent the main wing from stalling at high angles of attack) had been removed from the main wing. (3) Incorrect calculation of the airplane's empty weight center of gravity, resulting in the center of gravity being 0.1 inches beyond the aft limit. (4) Fuel flowing towards the aft portion of the fuel tanks during a climb to altitude and followed by an accelerated stall resulted in the center of gravity moving 1.1 inches beyond the aft limit.
The designer concluded that the aircraft had not been built according to the plans, but rather was "converted" to an "Aerocanard...an unauthorized, unapproved, rip-off design."
The aircraft was certificated in the experimental category.
The pilot had about 400 hours of flight time various Cozy aircraft; however, he had accrued only about 17 hours of flight time in the Cozy MK IV.
Data Source
Data provided by the National Transportation Safety Board (NTSB). For more information on this event, visit the NTSB Records Search website. NTSB# FTW97LA009