SEA03LA192

After landing and proceeding on the centerline, the pilot began to make a right turn following the taxi marker onto a taxiway. When the aircraft was off the runway, a brief and unusual nose wobble was detected. The nose of the aircraft then dropped to the runway and the propellers struck the pavement, causing the aircraft to come to an immediate stop. After separating from the aircraft, the nose wheel was observed approximately 3 to 5 feet from where it came to rest. It was observed that the wheel was smoking from the heat at the center bearing axle shaft, and there was a considerable amount of debris scattered near the front and rear of the aircraft. There was also debris from the nose wheel bearing housing found as far as 500 feet behind the aircraft. The nose landing gear structural attach points were substantially damaged. An FAA inspector reported the nose wheel bearing had failed and separated from the nose fork. The inspector also reported that the bearing and roller retainer on one side of the axle had disintegrated and was missing, while the bearing on the opposite side was void of any lubrication.

On September 20, 2003, approximately 1730 mountain daylight time, a Cessna 421B twin-engine airplane, N41053, sustained substantial damage while taxiing from a landing at the Driggs-Reed Memorial Airport, Driggs, Idaho. The aircraft was registered to Air Big Rock Inc., of Hinsdale, Illinois, and operated by a private individual. The commercial pilot and one passenger were not injured. Visual meteorological conditions prevailed for the 14 CFR Part 91 personal flight, and an instrument flight rules flight plan was filed. The flight departed Casper, Wyoming, at 1610.

According to the Pilot/Operator Aircraft Accident Report (NTSB form 6120.1/2), the pilot reported the landing was in a light wind to the southwest. After landing and proceeding on the centerline, the pilot stated that he "began braking to a walking pace" and began to make a right turn following the taxi marker onto a taxiway. The pilot reported that when the aircraft was off the runway, he felt a brief and unusual "nose wobble." The pilot further stated that the nose of the aircraft then dropped to the runway causing the propellers to strike [the pavement], and immediately stopping "with what seemed like no more than two feet of forward motion." The pilot also reported that upon departing the aircraft, the nose wheel was observed roughly 3 to 5 feet in front of the aircraft. The pilot stated that the wheel was smoking from the heat at the center bearing axle shaft, and there was considerable amount of debris scattered near the aircraft nose and behind the aircraft. The pilot related, "...debris from the nose wheel bearing housing was found as far as 500 feet behind the aircraft as we looked for any foreign matter that may have been on the runway. All of the debris was along the centerline, and the debris was too hot to be immediately handled."

On September 23, 2003, an FAA inspector, who visited the accident site, reported the nose wheel bearing had failed and separated from the nose fork. The inspector reported that the bearing and roller retainer on one side of the axle had disintegrated and was missing, while the bearing on the opposite side was void of any lubrication. The lower section of the nose fork had broken on each side of the wheel attach point, allowing the wheel to depart the aircraft. The inspector reported damage to the aircraft included the nose gear drag link truss assembly being ripped through the skin on both sides of its mounting areas inside the wheel well. Additional damage to the aircraft included the aircraft's nose, which was wrinkled, and both propellers which struck the runway pavement.