Primary finding
Probable cause
The pilot's failure to maintain flying airspeed which resulted in an aerodynamic stall.
Investigator assessment
Analysis narrative
The pilot stated that while on a straight-in final approach to land at about 200 feet above ground level, he pushed the propeller control forward and reduced the throttle control. The airplane then pitched nose down and he applied aft elevator control input with no effect. The airplane impacted the ground in about a 40-degree nose low attitude and nosed over. The propeller and propeller governor were examined and bench tested respectively with no evidence of pre-impact failure or malfunction.
Source record
Factual narrative
On July 13, 1995, about 0815 central daylight time, a Schweizer Aircraft Corp., G-164B, N76LS, crashed while landing at a private airstrip near Goodman, Mississippi. Visual meteorological conditions prevailed at the time and no flight plan was filed for the 14 CFR Part 137 aerial application flight. The airplane was substantially damaged and the commercial-rated pilot, the sole occupant, was not injured. The flight originated about 0730 from the accident airstrip. The pilot stated that while on a straight-in final approach to land at 200 feet above ground level, he pushed the propeller control in the cockpit forward and reduced the throttle control. The airplane then pitched nose down and he pulled aft on the control stick with no effect. The airplane impacted the ground in about a 40-degree nose down attitude then nosed over. The propeller and propeller governor were removed for further examination. The propeller governor was placed on a test bench and found to operate normally. Examination of the propeller revealed that the low pitch stop was correctly set at 10 degrees and the high pitch stop was set about 13 degrees less than specified (35 degrees). The propeller blade angle of the least and greater damaged blades was determined to be about 25 degrees and 40 degrees respectively. The two each pitch stop and two each fixed cam locating dowels were found to be failed and only one of the failed fixed cam dowels was located. Examination of the fracture surfaces of the failed dowels revealed evidence of overload failure. -