On August 17, 1998, approximately 2105 mountain daylight time, a Piper PA-31-350, N66906, sustained minor damage during an emergency landing at Denver International Airport, Denver, Colorado. The commercial pilot and copilot were not injured. The flight was being operated by Alliance Aviation, Inc., under Title 14 CFR Part 135, and an IFR flight plan had been filed. Visual meteorological conditions prevailed for the cargo flight which originated at Perry Stokes Airport, Trinidad, Colorado, at 1805, with an intended destination of Colorado Springs Municipal Airport, Colorado Springs, Colorado. According to the pilot-in-command, after departing Perry Stokes Aiprort, he and his co-pilot noticed a malfunction with the landing gear transition light. They attempted to recycle the landing gear, but the transition light remained illuminated. They notified the Colorado Springs tower and performed a fly by. The tower was able to visually verify that the left landing gear was down, and the right and nose landing gear remained in the up position. The crew circled the area for approximately one hour and thirty-five minutes, but all attempts to lower the gear by means of aerial maneuvers and emergency gear extension were unsuccessful. The crew made the decision to divert to Denver International Airport where expanded emergency ground services would be available. The crew declared an emergency, and a gear-up landing was performed. The aircraft came to rest approximately 2,500 from the threshold of runway 17L, 50 feet to the right of the centerline. The aircraft sustained minor damage to the right engine propeller blades. Post accident examination of the aircraft by an FAA inspector revealed that the landing gear sustained a hydraulic failure which was due to a ruptured hydraulic hose located in the right wheel well. The hydraulic braided steel hose had several braids broken and the rubber hose had been punctured and/or ruptured under pressure.