On December 17, 2004, about 1030 Pacific standard time, an Aircraft Manufacturer and Development Co. Alarus CH-2000, N285AM, was damaged when the door departed the airframe and struck the pilot's shoulder, while maneuvering near Jean, Nevada. American Aviation was operating the airplane under the provisions of 14 CFR Part 91. The certified flight instructor (CFI) was not injured and the private pilot sustained serious injuries; the airplane sustained minor damage. Visual meteorological conditions prevailed, and a flight plan had not been filed. The local check-out flight originated from Jean Airport about 1000. In a written statement, the private pilot reported that after departing the airport, he maneuvered the airplane into a climb until reaching 5,000 feet mean sea level (msl), where he configured the airplane in a level attitude. With the intention of performing a series of maneuvers for practice flight, he initiated a 30-degree turn to the left. While in the bank, the airplane's left canopy door suddenly became ajar, and he experienced difficulty flying the airplane. He attempted to regain control of the airplane, and about 2 to 3 seconds later, the door canopy separated completely from the airframe. After detaching, it struck the pilot's left shoulder, and then impacted the side of the fuselage. The pilot further stated that the separation of the left canopy door resulted in a rapid loss of airspeed and his ability to maintain control of the airplane, requiring an emergency decent and landing. He landed the airplane at Jean without further incident. After egressing the cockpit, both pilots noted that the canopy latching mechanism was still in the locked position, affixed to the airframe. After several doctor's visits, the pilot was determined to have suffered tendon damage to his left shoulder. A Federal Aviation Administration (FAA) inspector examined the airplane and interviewed the pilots after the accident occurred. He reported that the private pilot was undergoing a demonstration flight with the CFI, and remained pilot-in-command of the airplane throughout the flight. With the airplane cruising about 75 knots indicated airspeed, the pilot initiated a 30-degree bank, and upon entering the turn, the left canopy door separated from the airframe. While departing the airplane, the door struck the private pilot's left shoulder, ripped the nylon retaining strap from the composite fiber cockpit frame, and proceeded to slide along the left side of the fuselage, scratching the surface; no damage was found to the flight control surfaces. The canopy's lock/latch mechanism remained latched down in the "closed" position within the doorframe; the door was not located. During a telephone conversation with a National Transporation Safety Board investigator, a representative from Aircraft Manufacturer & Development Co. stated that after examining the hinges and pictures of the doorframe, they determined that the upper aft hinge of the canopy door failed first, followed by the forward hinge and a bolt attaching the bottom latch to the frame. The representative reported that the hinge had apparently undergone stress from the door remaining open during windy conditions or while the propeller was under power. The airplane's flight manual indicates in several locations that the door is to remained closed during such conditions. The representative added that the airplane is controllable with a door absent. The airplane is designed with both a left and right side door, both of which open upward, akin to a clamshell configuration. The canopy door is attached to the airframe via two congruent hinges oriented on the top of the airplane, and parallel the longitudinal axis. The pilot secures the door in the closed position via a handle, which manipulates the latch, locking the door to the doorframe.