SEA96LA005

The pilot of the RV-3 initiated a steeply banked right turn, after following another aircraft in a rapid climbing maneuver. During this turn, which was described by witnesses on the ground as extremely tight, the right wing was seen to separate from the fuselage. Examination of the wreckage revealed that the front wing spar had failed just outboard of its attach fitting, and the rear spar and rear spar doubler plate experienced a overstress separation through the attach bolt hole. The recording accelerometer found in the wreckage was indicating .2 G's more than the 9 G ultimate load limit published by the designer of the RV-3 aircraft plans.

On October 8, 1995, approximately 1640 Pacific daylight time, an experimental Chard RV-3A, N27RV, experienced an inflight separation of the right wing. The commercial pilot, who was the sole occupant, received fatal injuries, and the aircraft was destroyed. The personal pleasure flight, which departed Sunset Airpark about 40 minutes earlier, was being operated in visual meteorological conditions at the time of the accident. No flight plan had been filed, and there was no report of an ELT activation.

According to witnesses, the RV-3 followed an RV-8 in a steep climbing maneuver, and then initiated a level steeply banked turn. During this turn, which was described by witnesses on the ground as an extremely tight right turn, the right wing of the RV-3 was seen to depart the fuselage. The fuselage and remaining wing descended to the ground, impacting in an inverted position.

According to Van's Aircraft Change Notice CN-1, Van's Aircraft performed stress analysis calculations prior to releasing the RV- 3 plans, and the calculations determined that the major wing components should withstand loads of 9 G's before failure. In addition, Van's Aircraft performed a static load test on an RV-3 structure, which was built according to plans, and the main wing spar failed at 9 g's. The recording accelerometer found in the wreckage of N27RV was indicating a positive 9.2 G's.

Examination of the wreckage revealed that the forward wing spar had failed just outboard of the attach fitting, and the rear spar, and rear spar root doubler plate, had fractured through the spar-to-fuselage attach bolt hole.

The rear spar root and rear spar root doubler were sent to the NTSB Materials Laboratory for a metallurgical examination. The examination of both pieces revealed features and deformation patterns consistent with overstress separation. No evidence of fatigue failure was found.