Accident Flight
The flight was intended to gather data on the production configuration of the stall warning system and an improvement to the landing gear warning system, which involved changing from throttle position microswitches to manifold pressure switches on both engines. After takeoff, the landing gear warning horn and unsafe gear annunciation activated while the gear was retracted. The flight continued to 8,000 feet for planned stall tests. Following the tests, the crew found that the gear warning indication would not cease with the gear retracted unless throttles were reduced to about 14 inches manifold pressure.
Landing
The flight returned to the departure airport with the warning horn sounding and the unsafe gear light illuminated. On base leg, the pilot lowered the landing gear selector handle and confirmed three green down-and-locked lights. On a two-mile final, he confirmed twice that the gear was down and locked. Touchdown occurred on the main landing gear followed by the nose gear. When the pilot reduced back pressure, the aircraft pitched nose down as if the nose gear had collapsed. The airplane slid on the runway in a level attitude. After stopping, the pilot and passenger noted only the left main gear down-and-locked light was illuminated, and the gear selector was down. Fuel leakage was observed from the right fuel tank.
The pilot-rated occupant in the right front seat confirmed that gear extension was performed on base leg, three green lights appeared, and the indication was confirmed twice on approach. The landing was smooth on the mains then nose gear. The nose gear collapsed, and the airplane veered right. He believed the right main gear collapsed, and the airplane slid to the right, striking a taxiway sign with the right wing. The airplane spun about 150 degrees to the right and came to rest upright on grass.
Post-Accident Examination
Four days after the accident, an FAA inspector examined the airplane. With external power applied and the gear selector down, the gear warning horn sounded and no left main down-and-locked light was noted. This was attributed to a sheared main landing gear actuator attach point. Bypassing the left main gear down microswitch caused the left down-and-locked light to illuminate and the horn to stop. An attempt to raise the gear with the normal hydraulic pump produced no movement; powering the pump directly retracted the gear. No reason was determined for the failure to retract with aircraft electrical power. The nose and right main gears were extended by direct power to the pump, but attempts to forcefully unlock them were unsuccessful. The only discrepancy found was that the nose gear over-center locking device had "some play." A production airplane showed no such play. The accident airplane had accumulated about 827 hours and 372 flights. It was used for flight testing and had operated on at least six flights on grass and asphalt runways in the previous months, with no excessive strains noted on instrumented landing gear. Post-accident rigging checks by The New Piper Aircraft, Inc. revealed no abnormalities. Documents indicate that the nose gear and torque links were removed and inspected for wear limits on September 18, 2002, then reinstalled with a gear swing check on September 25, 2002. The airplane had accumulated 2 hours 54 minutes and 2 cycles since then before the accident flight.