On December 14, 1994, about 1630 mountain standard time, a Cessna 421C, N746CA, sustained substantial damage following the collapse of the nose and left main landing gear at the Chinle, Arizona, airstrip. The aircraft was owned and operated by Critical Air Medicine, Inc., of San Diego, California, and was on a 14 CFR Part 91 positioning flight to pick up a discretionary medical evacuation patient. Visual meteorological conditions prevailed and no flight plan was filed. The aircraft sustained substantial damage. The certificated airline transport pilot and the four medical crew members were not injured. The flight originated at Tuba City, Arizona, on the day of the accident at 1530. The accident was reported to the National Transportation Safety Board by a Federal Aviation Administration (FAA) airworthiness inspector from the San Diego Flight Standards District Office on January 3, 1995, after he discovered the damaged airplane in a hangar at the company base. The company did not complete a Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2), despite three separate requests. The pilot and a company mechanic onboard the aircraft at the time of the accident submitted explanatory letters to the FAA inspectors. According to both the pilot and mechanic, the approach and touchdown on the dirt airstrip were normal. The mechanic said he observed three down and locked gear indicator lights prior to touchdown. After touchdown on the main landing gear, the nose of the aircraft settled down past the normal nose gear contact point. The mechanic said that at that point, the aircraft nose went to the right and the aircraft began to slide sideways. The aircraft veered off the runway to the right and hit a barbed wire fence. Neither the pilot nor the mechanic reported any unusual "noises or sensations" from the nose gear during the landing. Both the pilot and mechanic stated that the landing gear tracks were straight on the runway until the nose gear "dug in and veered to the right." The FAA inspector who discovered the damage to the aircraft reported that the nose gear failed to the left with evidence of a side load. The upper right trunion fractured from the nose gear casting. According to the inspector, the fracture face appeared to be instantaneous overload, with no evidence of pre-existing cracks or flaws.