Aviation Accident Summaries

Aviation Accident Summary SEA96LA162

COTTAGE GROVE, OR, USA

Aircraft #1

N235WC

Conkey/Wapelhorst LANCAIR 235

Analysis

During the takeoff roll on runway 33, the left main landing gear collapsed as the aircraft was accelerating through about 55 to 60 knots. The pilot/co-owner of the aircraft reported that he was unable to identify any mechanical malfunction which have would allowed the left main gear to collapse. He also reported that the gear down lights were illuminated during the takeoff checklist. The reason for the release of the left main gear from the down and locked position could not be determined. However, a 5 to 10 knot quartering right crosswind existed at the time of the takeoff. Once the aircraft settled onto the left wing, the pilot was unable to maintain directional control, and the aircraft slid into another aircraft that was parked off the runway.

Factual Information

On July 20, 1996, approximately 1600 Pacific daylight time, a Conkey/Wapelhorst homebuilt Lancair 235, N235WC, registered to and being flown by a private pilot, was substantially damaged when the left main landing gear collapsed during the takeoff roll at the Cottage Grove airport, Cottage Grove, Oregon. The pilot and passenger were uninjured. Visual meteorological conditions prevailed and no flight plan had been filed. The flight, which was to have been local, was to be operated under 14CFR91. The pilot reported that he commenced the takeoff roll on runway 33, with an estimated wind of 05-10 knots from 010 degrees. As the aircraft accelerated through 55-60 knots the aircraft's left wing suddenly dropped. The pilot aborted the takeoff and the aircraft slid approximately 200 feet before leaving the west side of the runway and eventually impacting a parked Stinson 30 feet west of the runway. The pilot reported that he "could not determine any failures that (would have) caused the left wheel to collapse inboard." The Lancair main landing gear fold inboard into wheel wells in the lower fuselage. They are normally held in the down and locked position by hydraulic pressure. The pilot reported observing that all three gear down lights were illuminated during the takeoff checklist.

Probable Cause and Findings

release of the main landing gear locking mechanism for undetermined reason(s).

 

Source: NTSB Aviation Accident Database

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