On November 29, 2008, about 1236 Pacific standard time, an Adkins Ridge Runner II amateur-built experimental airplane, N825PB, impacted terrain following a loss of control during initial climb after takeoff from runway 32 at Portland-Mulino Airport, Mulino, Oregon. The private pilot, the sole occupant, received serious injuries. The airplane, which was owned and operated by the pilot, sustained substantial damage. Visual meteorological conditions prevailed, and no flight plan was filed for the local personal flight operated under 14 Code of Federal Regulations Part 91. The flight was originating when the accident occurred.

A witness, who was the pilot's uncle and held an Airframe & Powerplant (A&P) mechanic's certificate, reported that the pilot had recently purchased the airplane in Idaho and moved it to Oregon by ground transport. The pilot applied for, and received, operating limitations from the Federal Aviation Administration (FAA) for flight testing of the airplane. On the day of the accident, the pilot first performed taxi tests and then began taking off, climbing to about 10 feet above the ground, reducing power and landing back on the runway. The pilot completed a few of these runs and then taxied back onto the runway for another run, but did not reduce power after getting airborne.

The witness reported that the airplane climbed to about 75 to 100 feet above the ground and flew pass the end of the runway. It was flying "very slow." Then the pilot banked the airplane "for a right hand turn to return to the runway." When the bank angle reached about 30 degrees, the wing "suddenly dropped" and "as the wing dropped, the nose of the aircraft dropped also." Within 1 to 2 seconds the airplane hit the ground.

The pilot reported that he taxied onto the runway "for taxi test and possible take off." He advanced the throttle and noted that the tachometer "only went to 4,000 rpm." The airplane lifted off the runway and climbed to about 150 feet above the ground. It would not "climb higher or speed up." The airspeed was reading about 45 to 50 knots. The pilot "started looking for a place to land" and seeing obstacles ahead and to the left, he executed a "shallow right turn back towards the airfield." The airplane stalled "without notice" and there was not "any time or space to recover."

Review of photos of the airplane at the accident site taken by local authorities revealed that the airplane came to rest in a nose down position in a flat grassy field. The engine was displaced rearward, and the forward portion of the fuselage was crushed and compressed aft. Both wings displayed skin wrinkles.

The pilot reported that he had accumulated 240.7 hours total flight time of which 0 hours were in the accident make and model airplane.

Following the accident, the mechanic examined the wreckage and found that the propeller was in "high pitch preventing the engine from turning up to more than 4,000 rpm, limiting the horsepower." The mechanic also reported that the accuracy of the airspeed indicator had not been checked, and "it may have been in error."