NTSB Factual Report

On February 11, 2001, approximately 1720 Pacific standard time, an Aero Commander AC-690, N690AC, experienced a collapse of the nose gear during the landing roll at Mahlon Sweet Airport, Eugene, Oregon. The private pilot and his passenger were not injured, but the aircraft, which is owned by Gisler Management Inc., and operated by the pilot, sustained substantial damage. The 14 CFR Part 91 personal flight, which departed Redmond, Oregon, about 25 minutes earlier, was operating in instrument meteorological conditions at the time of the accident. The aircraft had been on an IFR fight plan while en route. There was no report of an ELT activation.

According to the pilot, while taxiing for departure at Redmond, he experienced some difficulty maintaining directional control with the nose wheel steering. He thought this was happening as a result of taxiing in "very icy conditions" with a gusty quartering tailwind. After takeoff from the icy runway, he attempted to retract the gear, but the "Gear Unsafe" light did not extinguish. He then recycled the gear four separate times, using full-left and full-right rudder inputs, but the "Gear Unsafe" light did not go out. Then, because of the severe weather conditions at Redmond, the pilot elected to continue on to his intended destination of Eugene.

Upon reaching the ILS final approach fix for runway 16 at Eugene, the pilot attempted to lower the landing gear. Although the green "Gear Down" lights came on for both of the main gear, the red "Gear Unsafe" light remained illuminated, and there was no green light for the nose gear. The pilot recycled the landing gear a number of times, both with and without rudder pedal application, but he was unable to get the green "Gear Down" light to illuminate for the nose gear. After a visual check of the nose gear by the pilot, and a confirmation by the pilot of an aircraft waiting for departure, the pilot of the subject aircraft determined that the nose gear was not fully extended. Since he had already recycled the gear a number of times, both at Redmond and Eugene, he elected to continue the landing. Although the touchdown was successful, as the nose gear was lowered to the runway surface, it collapsed back into the wheel well, allowing the nose of the aircraft to settle onto the runway surface. The pilot maintained directional control with light directional braking, and the aircraft slid about 5,000 feet down the runway.

During a post-accident inspection of the nose gear, it was necessary to use a pry bar in order to free the gear from the gear well. Once free, it rotated to the fully-extended and locked position, and the corresponding green light illuminated in the cockpit. Although the gear was then extended, the nose wheel, which had rotated to its limit, could not be centered until the bolts holding the bushing collars at the base of the nose gear strut oleo housing were loosened. The inspection process did not determine whether the gear had jammed at its limit during the taxi and takeoff at Redmond, or whether it had done so as it collapsed into the wheel well at Eugene. There were no identifiable anomalies detected in the nose gear retraction/extension system, and it could not be positively determined why the gear did not fully retract or extend.

NTSB Probable Cause

an undetermined malfunction of the nose gear system which resulted in the failure of the nose gear to fully extend and lock prior to landing.