Mammoth Lake, CA, USA
N6744P
Piper PA-24-250
The commercial certificated pilot was conducting a cross-country flight under Title 14, CFR Part 91. The pilot said when he arrived at his destination airport, he did not get a green down and locked light for the landing gear, and elected to go-around. He said he cycled the landing gear up and down twice, saw the green down and locked light both times, and proceeded to land. He reported that upon touchdown, the right main landing gear collapsed, and the airplane exited the right side of the runway and struck a snowbank. The pilot stated that there were no known preaccident mechanical anomalies with the airplane. Postaccident inspection of the airplane by an independent aviation mechanic hired to repair the airplane, disclosed that the main landing gear maintenance did not appear to be in compliance with an applicable FAA airworthiness directive (AD), AD 77-13-21, Amendment 39-3093, effective December 16, 1977. That AD defines the actions/inspections necessary to maintain the landing gear in an airworthy condition, and to preclude a malfunction or collapse. A review of the airplane's maintenance logbooks indicated only partial compliance with the AD. The aviation mechanic repairing the airplane said that numerous landing gear components were worn well beyond the limits set forth in the AD and associated service letter.
On March 30, 2006, about 0900 pacific standard time, a Piper PA-24-250 airplane, N6744P, sustained substantial damage during landing when the right main landing gear collapsed. The airplane was being operated by the pilot as a visual flight rules (VFR) cross-country personal flight under Title 14, CFR Part 91, when the accident occurred. The solo private pilot was not injured. Visual meteorological conditions prevailed, and no flight plan was filed. The airplane departed Gillespie Field, San Diego, California, about 0600. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on March 30, the pilot said when he approached the airport for landing, he did not get a green down and locked light for the landing gear, and proceeded to go-around. He said he cycled the landing gear up and down, and saw a green down and locked light. He again cycled the landing gear, and again saw the green down and locked light. The pilot said he elected to land, and upon touchdown, the right main landing gear collapsed. He said the airplane exited the right side of the runway and struck a snow bank, collapsing the nose gear. He indicated that prior to the accident there were no known mechanical anomalies with the airplane. He said the right wing received structural damage, in addition to damaging the landing gear and propeller. Federal Aviation Administration (FAA) Airworthiness Directive (AD) AD 77-13-21, Amendment 39-3093, effective December 16, 1977, specifies the actions necessary to maintain the accident airplane's landing gear extension/retraction system in a serviceable and airworthy condition. The AD specifies the inspection of landing gear components, and the replacement of unserviceable components, in order to help prevent landing gear collapse. Paragraph (a) specifies the inspection and replacement of landing gear components that exceed specified wear limits as referenced in Piper Service Letter No. 782B. Paragraph (b) specifies the condition inspection, and replacement interval for the landing gear bungees. The criteria for paragraphs (a) and (b) differ, and require separate logbook entries, or at least separate notations to show full compliance with the AD. An inspection of the accident airplane's maintenance logbook by the IIC noted continued replacement of the landing gear bungees at the specified interval in accordance with paragraph (b). However, there were no entries regarding the inspections of the landing gear components required in accordance with paragraph (a). An independent aviation mechanic hired to affect the repairs, said numerous components were worn well beyond the limits set forth in the Piper Service Letter.
The collapse of the right main landing gear during landing, which resulted in a loss of directional control and an on-ground encounter with a snowbank. A factor associated with the accident was other maintenance personnel's inadequate inspection of the landing gear system.
Source: NTSB Aviation Accident Database
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