Accident Overview
On July 27, 2012, about 0846 eastern daylight time, a Mooney M20TN, N411JL, experienced a severe nose pitch-up while climbing through flight level (FL) 180 to FL230. The private pilot, the sole occupant, initiated an emergency descent. During the attempted landing at the Lenawee County Airport (ADG), Adrian, Michigan, the airplane landed short of Runway 23. The nose gear collapsed and the main landing gear separated, resulting in substantial damage to the airplane. The pilot was not injured.
Flight History
The flight departed Wittman Regional Airport, Oshkosh, Wisconsin, about 0732 on an instrument flight rules (IFR) flight plan with Manassas Regional Airport (HEF), Manassas, Virginia, as the intended destination. Visual meteorological conditions prevailed at the time of the accident. The pilot reported departing under visual flight rules (VFR) and hand-flying for about 20 minutes before engaging the autopilot. While passing Muskegon, Michigan, he activated his IFR flight plan and received an air traffic control (ATC) clearance to climb to 17,000 feet mean sea level (msl). The pilot reported that during the climb, his backup oxygen system was not working. He descended to 15,000 feet msl to change to the airplane's built-in oxygen system. After confirming it worked, he resumed the climb.
At 0843:12, ATC instructed the pilot to climb to FL 230, which he acknowledged. The pilot reported that during the climb, the airplane experienced a "violent pitch up." The pitch up occurred when the airplane was climbing approximately through FL180. The pilot stated it was a rapid pitch up with no warning, requiring extreme forward yoke pressure (estimated 100 to 150 pounds with both hands) to prevent a possible stall.
At 0846:43, the pilot informed ATC of an issue. The pilot later declared an emergency, stating he could not control the airplane. Another aircraft on frequency suggested the pilot sounded hypoxic, but the pilot stated he had his oxygen mask on and was not hypoxic, attributing his sporadic radio calls to the stressful situation.
The pilot reported keeping both hands on the yoke to avoid stalling and spinning. He did not use the manual trim wheel or attempt to disengage the autopilot via the power switch or circuit breakers. He attempted to use the manual electric trim switch on the yoke, but it had no effect. He made no rudder application to avoid an incipient spin. The pilot encountered multiple violent pitch oscillations. During one oscillation, the pilot seat broke, allowing him to use his knees to apply forward pressure to the yoke.
The pilot eventually descended to 3,000 feet and regained some control. He decided to land at ADG. Using his knees for forward yoke pressure, he attempted an approach to Runway 23 but landed hard in the grass short of the runway.
Pilot Information
The 68-year-old private pilot held a private pilot certificate with single-engine land, glider, and instrument airplane ratings. He held a third-class medical certificate issued January 3, 2011, with a limitation of wearing corrective lenses. He had 917 total flight hours, with 346 hours in the accident airplane.
Aircraft Information
The airplane was a single-engine Mooney M20TN, serial number 31-0096, manufactured in 2008, powered by a 280-horsepower Lycoming TSIO-550-G1 engine. The last annual inspection was completed December 2, 2011, with 410.5 hours total time at that inspection; total time at the accident was 594 hours. The airplane was equipped with a Garmin G1000 Integrated Avionics System and a Garmin GFC 700 Automatic Flight Control System (AFCS), a 2-axis autopilot and flight director. The AFM Supplement for the GFC 700 included emergency procedures for an autopilot out-of-trim condition, which involved depressing and holding the A/P DISC/TRIM INTER switch, maintaining aircraft control, re-trimming using the trim wheel, and turning off the A/P POWER switch. The supplement also warned against attempting to overpower the autopilot or manually fly with the autopilot engaged.
Meteorological Conditions
At 0853, the surface weather observation at ADG was: wind light and variable, sky clear, visibility 10 miles, temperature 24°C, dew point 19°C, and altimeter 29.85 inches of mercury.
Wreckage and Impact
The airplane impacted terrain about 450 feet short of Runway 23. The main landing gear and doors sheared off, the nose gear collapsed into the wheel well, and propeller blades were bent as the airplane skidded through grass, across the asphalt threshold, and stopped after another 450 feet. The empennage and fuselage were twisted at the attach points, the left wing was bent outboard, and all flight control surfaces were damaged. The landing gear handle was down, flaps were up, and no burnt odors were noticed. Items found in the cockpit included a backup oxygen bottle and mask, two oxygen masks with boom mikes, a CO2 detector, blood oxygen monitor, two headsets, and a flight bag.
Flight control examination revealed: the tail stabilator was in the full down position; pitch trim was 2 notches from full nose up; pitch trim continuity was verified but travel limited due to tail damage; electric pitch trim operative but travel limited; elevator control continuity verified; yaw control continuity verified; rudder electric trim operative; roll control continuity verified; speed brakes deployed and retracted normally.
Examination Findings
Multiple examinations of the flight controls and autopilot system were conducted. On August 21, 2012, with NTSB oversight, the autopilot preflight test completed successfully, electric pitch trim moved correctly, the AP disconnect/Trim Interrupt switch functioned, and autopilot operated normally in heading and pitch modes. No evidence of electrical fire or short was found. A September 24, 2012 examination by an avionics service facility with FAA oversight found no defects in autopilot tests; all modes functioned normally, and no relevant fault codes were found. Static wicks tested within limits.
On January 31, 2013, the pitch servo had a breakaway torque of 50 in/lb (spec: 42+/-6 in/lb), the pitch trim servo had 70 in/lb (spec: 70+/-9 in/lb), and the roll servo could not be tested due to a loose nut but had passed self-tests.
An NTSB radar performance study showed the initial upset was not discernible, but calculated airspeed fluctuated over 100 knots afterward. The airplane descended from 15,000 feet to 3,800 feet in about 6 minutes with a 1,866 fpm descent rate, consistent with a spiraling descent. Groundspeed was as slow as 50 knots, and the flight stabilized around 0906 with increasing airspeed.