Piper PA-30 N1WE accident near Culpeper, Virginia

Probable cause

The pilot's failure to use the manufacturer's checklist to troubleshoot the perceived malfunction and thereby ensure the position of the landing gear before landing. The reason the landing gear were not down and locked could not be determined, as no mechanical failures or anomalies were reported before the accident or observed during postaccident testing.

NTSB analysis

While approaching the destination airport, the pilot did not observe the green landing gear down-and-locked light illuminate when she moved the landing gear handle to the "down" position. She manipulated the handle several times and still did not observe the green light. The pilot stated that after she tried to manually extend the landing gear, the nose landing gear appeared to be extended in the viewing mirror, and she heard a "whistling" sound consistent with gear extension; however, the green down-and-locked light in the cockpit was not illuminated. The pilot continued to the airport to land. She reported that she heard the gear warning horn during the landing flare, but that it was "too late" to abort the landing, and the landing gear collapsed upon touchdown.

After the accident, the landing gear was cycled and operated normally, although the gear down-and-locked light did not appear to be illuminated. However, the airplane’s navigation lights were observed to be in the “on” position. By design, the gear down-and-locked light illuminated more dimly with the navigation lights on (nighttime use) than with the navigation lights off (daytime use). When the emergency landing gear extension procedure was performed after the airplane’s navigation lights were turned off, the gear extended and locked down, and the corresponding gear down-and-locked light was visibly illuminated. The emergency checklist that the pilot used during the accident flight did not instruct the pilot to confirm the position of the navigation lights, and the pilot stated that she did not consult the pilot's operating handbook (POH) during the flight. If the pilot had reviewed the emergency gear extension checklist in the POH or if the checklist she used had included a check of the navigation lights, the pilot may have been better able to determine the position of the landing gear before touchdown.

Text from the NTSB. Open the NTSB docket for ERA12LA188 for the full record.