2021 Mooney M20M Accident Near Victoria, Minnesota (N9156Z)

Accident Overview and Flight History On August 7, 2021, at approximately 1740 central daylight time, a Mooney M20M airplane, registration N9156Z, was destroyed in an accident near Victoria, Minnesota. The private pilot and two passengers, one of whom was a student pilot, sustained fatal injuries. The aircraft was operating as a personal flight under Title 14 Code of Federal Regulations Part 91. ADS-B data indicated the aircraft departed Chandler Field Airport (AXN) in Alexandria, Minnesota, at 1654 on an instrument flight rules (IFR) flight plan. It climbed to 5,000 feet mean sea level (msl) en route to Flying Cloud Airport (FCM) in Minneapolis, Minnesota. The pilot later descended to 3,000 feet msl and was cleared for the instrument landing system (ILS) approach to runway 10R at FCM. At 1738:39, the pilot contacted the FCM tower, stating, “Mooney 56 Zulu…ah…with you.” The pilot did not respond to repeated clearances. About 10 miles from the runway, the aircraft tracked left of the ILS course and descended below 2,700 feet msl. At 1739:22, the pilot acknowledged the landing clearance with “ah 56 Zulu.” The aircraft then turned right back toward the approach course and continued descending, triggering a low-altitude alert. The pilot acknowledged the alert, but no further transmissions were received. The aircraft subsequently made an abrupt left turn and rapid descent, losing radar contact before impacting the ground and catching fire. Witnesses reported a loud popping noise and observed the aircraft in a rapid descent with at least one wing folded up. A doorbell security video showed the aircraft upright and in a nose-high attitude at impact, with both wings and the right stabilizer deflected upward. A King Air pilot who heard the communications noted the pilot sounded “stressed” and “confused.” ## Personnel and Aircraft Information The pilot transitioned from a paper to an electronic logbook in February 2021. No instrument approach procedures were logged in the electronic logbook, and the last instrument approach in the paper logbook was in November 2020. The pilot’s most recent flight review used visual procedures only. A flight instructor described the pilot as “very safety conscious” and “detail oriented” but was unaware of a safety pilot flying with the pilot in the six months before the accident. A friend of the pilot, with about 3,000 hours of experience, stated the pilot flew frequently with him and used a yoke-mounted Garmin 650 as an electronic flight bag. The friend was confident the pilot would have attempted to engage the autopilot during the instrument approach and certain the student pilot passenger would not have flown in instrument conditions. The friend described Mooney pitch control as “challenging” and noted the pilot discussed using pitch trim and “pedal turns” (half-standard-rate turns primarily with rudder control) for instrument flight. ADS-B data from a January 2021 flight showed a series of shallow turns for about 50 minutes, which the friend believed were “pedal turns” practice. The friend often acted as a safety pilot for instrument approach practice, but they had not flown together in 2021 due to the COVID pandemic. The pilot’s personal weather minimum was an 800-foot ceiling, and he usually flew GPS approaches rather than ILS approaches. The friend was unaware of another safety pilot or flight simulator use by the pilot in the years preceding the accident. The Airplane Flight Manual listed the maximum positive load factor with flaps up as 3.8 Gs and the maneuvering speed (VA) as between 111 and 126 knots calibrated airspeed. In 2017, the pilot reported to his insurance company that he lost directional control during landing, striking runway edge lights and damaging the right horizontal stabilizer. The damage was repaired in 2018, and the friend attributed the excursion to “a distraction during the landing rollout.” ## Meteorological and Airport Information Pilots of a King Air that landed immediately before the accident reported entering clouds at about 4,500 feet msl and breaking out on final approach at about 1,000 feet above ground level. The monitoring pilot confirmed similar altitudes and reported no turbulence in the clouds. The Airplane Flight Manual limitations and the 2017 runway excursion details are repeated in the source under the Airport Information section. ## Wreckage and Impact Information The aircraft impacted the ground on a northerly heading. The left horizontal stabilizer and left elevator were found about 720 and 800 feet southwest of the accident site, respectively. A 6-inch section of the main wing spar upper cap splice plate was found about 300 feet southwest. Postaccident examination revealed the flap actuator jackscrew threads were consistent with the flaps in the retracted position. The speedbrakes extended and retracted freely with no deformations. Both vacuum pumps were disassembled, with all components accounted for; the vanes and drive couplers were intact, and the attitude gyro and turn/slip rotors showed indications of rotation at impact. The propeller separated from the crankshaft due to impact damage, and all three blades exhibited chordwise and leading-edge scaring. The left horizontal stabilizer separated about 10 inches outboard of the airplane centerline. The left elevator separated from the horizontal stabilizer and fractured into two pieces. The left elevator hinges were intact on the horizontal stabilizer, and the hinge blocks were pulled from the elevator. The damage and deformation of the left horizontal stabilizer and elevator were consistent with separation in an upward direction. The left elevator control rod attach bolt remained installed in the left elevator but was deformed inboard about 45°. The bolt threads had some smearing, and the nut and cotter pin were not located in the recovered wreckage. No evidence indicated fretting on the elevator around the bolt location. Both wings fractured near the outboard ends of their respective main landing gear wheel wells. The lower spar cap on both wings showed no deformation adjacent to the main spar fracture locations, whereas the upper spar caps exhibited S-bending. All examined fractures had a dull, grainy appearance consistent with overstress separation, with no evidence of corrosion or pre-existing fractures. No preaccident mechanical failures or malfunctions with the airplane or engine were observed that would have precluded normal operation. ## Additional Information: Spatial Disorientation and Instrument Experience The FAA’s Airplane Flying Handbook (FAA-H-8083-3B) describes hazards of flying when the ground or horizon are obscured, noting that the vestibular sense can confuse the pilot. Due to inertia, the inner ear cannot detect slight attitude changes or accurately sense uniform-rate attitude changes over time. False sensations can lead to spatial disorientation, where the pilot believes the attitude has changed when it has not. FAA regulations require pilots to conduct and log a minimum of six instrument approach procedures every six months to maintain IFR currency. The FAA’s Information for Operators 15012 (September 8, 2015) allows the following methods: actual instrument flight conditions in an aircraft; simulated instrument conditions using a view-limiting device with a safety pilot; simulated instrument conditions in an FAA-approved flight simulator/full flight simulator, flight training device, or aviation training device; or a combination of these methods. ## Medical and Pathological Information The Midwest Medical Examiner’s Office in Ramsey, Minnesota, performed an autopsy on the pilot, whose cause of death was multiple blunt force injuries. Toxicology testing by the FAA Forensic Sciences Laboratory detected diphenhydramine in the pilot’s liver and heart tissue. Ethanol was not detected in the brain tissue, and testing was inconclusive for ethanol in the liver tissue. Blood specimens were not available. Diphenhydramine is a sedating over-the-counter antihistamine (commonly marketed as Benadryl) used for colds, allergies, and insomnia. It carries a warning that it may impair mental and physical ability to perform hazardous tasks, including driving or operating heavy machinery. FAA guidance indicates a 60-hour postdose observation time before flying after using this medication, which is not for daily use. An FAA study found that pilots who had used an antihistamine such as diphenhydramine were involved in more fatal accidents in instrument meteorological conditions than pilots who had used nonsedating antihistamines. ## Tests and Research The NTSB conducted a performance study based on ADS-B data. After 1739:00, the aircraft made increasingly tight turns at speeds above VA. While on the runway heading during final approach, the airspeed slowed to about 80 knots. At about 1738:45, the airspeed increased to about 140 knots, the flight track diverged left of the approach course, and the aircraft descended about 300 feet. The aircraft then turned right, and the descent continued, with erratic altitude and airspeed fluctuations during the turns. At about 1739:25, the aircraft began its final left turn. About 13 seconds later, the left-turn radius tightened markedly. The aircraft descended at more than 7,000 feet per minute, and its airspeed increased to more than 180 knots. As the left turn tightened and airspeed increased, the bank angle and load factor increased. By 1739:43, the estimated 4.8-G load factor exceeded the manufacturer’s maximum positive load factor. About one second later, the increased speed and tighter turn resulted in a load factor of more than 8 Gs. From 1739:43 to 1739:45, the groundspeed increased about 40 knots, and the left turn rate accelerated with a 046° heading change. During this two-second timeframe, the aircraft descended below the altitude of the overcast cloud deck.