On October 17, 1994, at 1742 hours mountain standard time, a Cessna 402, N402SW, landed gear up and veered off runway 3 at the Grand Canyon Airport, Grand Canyon, Arizona. The airplane was being operated as a sightseeing flight under 14 CFR Part 135 when the incident occurred. The airplane sustained minor damage. The certificated commercial pilot and eight passengers were not injured. One passenger received minor injuries. The flight originated in Las Vegas, Nevada, at 1500 hours. Visual meteorological conditions prevailed and a company visual flight rules flight plan was filed. According to Federal Aviation Administration (FAA) inspectors, a bellcrank in the left main landing gear system fractured, jamming the landing gear in the up position. After getting a gear not safe indication, the pilot orbited the airport about 90 minutes to burn fuel before landing. During the landing roll, the airplane veered left and came to rest about 50 feet east of runway 3 at midfield. The last maintenance inspection of the landing gear system was a 200-hour inspection accomplished on September 20, 1994, about 71.1 flight hours before the accident. At the time of the inspection, there were no discrepancies noted with the bellcrank. An examination of the landing gear by the pilot during his preflight walk-around check of the airplane is a checklist item contained in the aircraft manual. Review of Service Difficulty Reports (SDRs) for Cessna 402A airplanes revealed two previous left main landing gear malfunctions as a result of broken bellcranks. The submitters of the two SDRs both recommended increasing the inspection criteria of the bellcrank. As a result of this incident, Federal Aviation Administration inspectors revised the operator's maintenance program by requiring the landing gear system be inspected every 50 hours of aircraft operation.