Piper PA30 N8924Y accident near Rock Hill, South Carolina

Probable cause

The pilot’s exceedance of the airplane's critical angle of attack while troubleshooting a landing gear indication, which resulted in an aerodynamic stall at low altitude.

NTSB analysis

The pilot had recently purchased the airplane and departed on a multileg flight to pick up the airplane and its logbook and return to the pilot’s home airport. Automatic dependent surveillance-broadcast (ADS-B) data showed that about 2 hours into the last leg of the flight, the pilot descended and began to maneuver several miles from the intended airport. At that time, the pilot initiated several phone calls to a mechanic to report that the landing gear circuit breaker kept popping. The mechanic provided guidance on the manual gear extension process. About 45 minutes later, during the final call to the mechanic, the pilot stated that he needed to add “some power,” and then the call dropped. At that time ADS-B data showed the airplane at an altitude of 1,025 ft mean sea level (msl) and a groundspeed of 63 knots.

Examination of the engines and airframe revealed no evidence of any preimpact mechanical malfunctions that would have precluded normal operation. All landing gear were in the downand-locked positions at the time of the accident. Laboratory testing of the green landing gear “down locked” light bulb revealed that the bulb filament had fractured and that no hot filament stretching was present, indicating that the bulb was either burned out before impact or not illuminated at the time of impact. The timing of the filament fracture could not be determined.

Given the burned-out light bulb and the position of the landing gear at the time of the accident, it is likely that the landing gear indication (the popped circuit breaker) was erroneous and that the gear was down and locked while the pilot was attempting to manually lower the landing gear. Given that ADS-B data showed that the airplane was at 1,025 ft msl and 63 knots groundspeed at the time that the pilot indicated that he needed to add power, it is likely that, with his focus on the manual gear extension process and phone calls, the pilot failed to monitor his airspeed. The airplane likely slowed below its stall speed, resulting in an exceedance of the airplane's critical angle of attack, which led to an aerodynamic stall from which the pilot could not recover because of the airplane’s low altitude.

Text from the NTSB. Open the NTSB docket for ERA22FA047 for the full record.