On April 15, 2003, at 2041 mountain daylight time, a Swearingen SA226TC, N229AM, operated by Superior Aviation, Inc., of Kingsford, Michigan, as flight HKA 1813, was substantially damaged during a wheels-up landing on runway 35L at Denver International Airport, Denver, Colorado. The airline transport certificated captain and commercial certificated first officer were not injured. Visual meteorological conditions prevailed, and an IFR flight plan had been filed for the nonscheduled domestic cargo flight being conducted under Title 14 CFR Part 135. The flight originated at Gunnison, Colorado, approximately 2000. The following is based on the accident report and a written statement submitted by the captain. The flight had been radar vectored behind and was following a heavy jet for an approach to runway 35L. As a result, it was mutually agreed that the approach would be conducted at a slightly higher altitude than normal to avoid any possible wake turbulence. The first officer, who was flying the airplane, called for the landing gear to be lowered. When the captain placed the gear handle in the DOWN position, he noted red IN-TRANSIT lights and remarked to his first officer, "It's happening again. The nose is not coming down." He recycled the landing gear, but got the same result. He consulted the emergency checklist and extended the landing gear manually. He felt confident that the landing gear was down and locked because he "heard the normal 'clunk feel' and airspeed started to decay." In addition, when power was reduced to FLIGHT IDLE, the GEAR UNSAFE warning horn did not sound. He wrote, "In the past, when there was no green indication in this aircraft with the use of the emergency extension system, the gear remained down and locked." He felt the wheels contact the runway, but the airplane continued to sink and then he heard the propellers striking the pavement. The first officer's statement corroborated that of the captain's. He added, "Sometimes, the squat switch in the wheel well for the position lights freeze and are showing red when they should be green or out." Following the emergency checklist, the landing gear was manually extended and he noted 2,000 pounds of hydraulic pressure. This made him feel confident that the landing gear was down and locked. According to an FAA aviation safety inspector who examined the airplane, the nose landing gear was partially extended, but the main landing gear was not. Propeller blade fragments penetrated the fuselage and breached the pressure vessel.