Aircraft: Piper Twin Comanche Injuries: None. Location: Culpeper, Va. Aircraft damage: Substantial.
What reportedly happened: While on approach to the destination airport, the pilot moved the landing gear handle to the “down” position and noted that the green landing gear down-and-locked light didn’t illuminate. He recycled the landing gear several times but still the lights did not illuminate.
He attempted to manually extend the landing gear, noting that the nose landing gear appeared to be extended in the viewing mirror, and the noise was consistent with gear extension, however, the green down-and-locked light in the cockpit was not illuminated. He continued to the airport to land.
He reported hearing 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 than with the navigation lights off.
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. The pilot did not consult the pilot’s operating handbook during the flight.
Investigators determined that if the pilot had reviewed the emergency gear extension checklist in the POH or if the checklist 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.
Probable cause: The pilot’s failure to use the manufacturer’s checklist to troubleshoot the perceived malfunction and 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 post-accident testing.
NTSB Identification: ERA12LA188
This February 2012 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.