On October 27, 1998, at 1328 hours mountain standard time, a Beech C90, N37PT, veered off the runway and collided with an electrical utility box during takeoff at the Sedona, Arizona, airport. The aircraft sustained substantial damage; however, neither the flight instructor nor his student was injured. The aircraft was being operated by Hayden Leasing LC under 14 CFR Part 91 of Federal Aviation Regulations as an instructional flight when the accident occurred. The flight was originating from the Sedona airport as a cross-country flight to Scottsdale, Arizona. Visual meteorological conditions prevailed at the time and no flight plan was filed. The instructor reported that he was taking off on runway 21 at Sedona when the aircraft began drifting to the right as he accelerated through 80 knots. He checked the power and found it stabilized at 1,230 pounds of torque. He applied full left rudder and 3/4 left aileron to counteract the turn but was unable to stop the drift. He rotated at 90 knots and immediately heard the sound of the gear warning horn. After becoming airborne, he was advised by another aircraft that his right gear was not visible. Instead of retracting the gear, he made a low pass over the field for further visual confirmation. He was advised by an FBO operator on the field that his right gear assembly was missing. The pilot informed the FBO operator that he was going to continue to Scottsdale, but a few minutes later decided that it was possible that the loss of the gear assembly might have also initiated a fuel leak. At this point, he declared an emergency with Albuquerque center and made and emergency landing at Ernest A. Love Field, Prescott, Arizona. During the landing roll the pilot shutdown the right engine and feathered the propeller. At 55 knots he gradually lowered the right wing toward the runway. As the wing contacted the runway, the aircraft began a right arc off the runway, coming to rest between the runway and taxiway. An inspection of the runway at the Sedona airport revealed tire tracks diverging from the right side of the runway at 1,050 feet from the approach end. The track continued until it terminated at a cement electrical service box 322 feet from the point where the tracks left the runway. Impact marks were found on the cement box and the right main gear assembly was found on the ground about 152 feet beyond the box. The fractured portion of the upper torque link was submitted to the Safety Board's Materials Lab for examination. The examination revealed the fracture surface exhibited characteristics consistent with an overstress separation. The instructor and the ground witnesses said weather was not a factor in this accident.