What happened
On August 16, 2018, at approximately 1100 mountain daylight time, a Cessna R172E, registration N146AC, was involved in a forced landing following takeoff from the USAF Academy Airfield (AFF) in Colorado Springs, Colorado. The aircraft, operated by the United States Air Force for instructional purposes, was performing a local flight in visual meteorological conditions.
During the takeoff roll on the 4,480-foot asphalt runway, the student pilot rotated the aircraft at approximately 60 mph. While the engine appeared to be operating normally with a fuel flow of 14 gallons per hour and 2,800–2,900 rpm, the aircraft reached only 100 feet above ground level before it stopped climbing. As the airspeed decreased, the flight instructor took control, set the flaps to 10°, and lowered the nose to maintain a speed of 55–60 mph in an attempt to use ground effect to regain airspeed. To avoid a tree line, the instructor turned the aircraft to the right and executed a forced landing in a field. The aircraft landed on its main wheels, but the nose gear struck rough terrain, causing the airplane to nose over. There were no injuries to the flight instructor or the student pilot, though the aircraft sustained substantial damage to the wings and fuselage.
The investigation
Investigators examined the engine, which was a 210 horsepower Continental IO-360-DB. During initial testing at a manufacturer's facility, the engine reached full rpm and rated horsepower, but subsequent runs showed it only reaching 2,600 rpm. The investigation identified that two fuel nozzles were partially clogged; once cleaned, the engine returned to normal operation, reaching approximately 2,830 rpm.
A bench test of the propeller governor showed no evidence of failure or malfunction prior to the accident, and the component met all specifications.
Findings
Post-accident examination of the airframe, engine, and propeller governor provided no evidence of mechanical malfunctions or failures that would have prevented normal operation. Consequently, the specific reason the aircraft failed to maintain a climb could not be determined.