Bartow, FL, USA
N1149T
Mooney M20J
The accident pilot and his wife were assigned the No. 4 position in a formation flight. Flight data indicate that, throughout the flight, the accident airplane’s path, altitude, and speed closely followed those of the lead airplane. Approaching the landing airport, the flight-lead instructed the other pilots in the formation to “Go extended trail,” and all complied and were in-trail behind the flight lead to enter the traffic pattern. Subsequently, the accident airplane’s flightpath became irregular when, about 1,500 ft past the lead airplane’s turn, the accident airplane began a turn from downwind to base leg during which the bank angle varied from 5° to 20°. It leveled off on the base leg, then turned sharply right toward the runway, passing through the runway heading before turning left and steeply descending. Witnesses at the airport reported seeing the accident airplane “closing in” on airplane No. 3 before making a sharp right turn. The airplane impacted the ground about .6 nautical mile from the runway threshold. Examination of the airplane revealed that the landing gear was in the UP position and the flaps were extended to 10°, which is not consistent with normal landing configuration upon the completion of the landing checklist, which should be performed on the downwind leg of the traffic pattern. No preimpact anomalies or malfunctions were identified during the examination that would have prevented normal operation. Airplane manufacturer lift data indicated that for a no-flaps configuration, lift dropped off just before 15° angle of attack. The airplane’s calculated angle of attack increased to more than 14° immediately before the airplane descended rapidly to the ground. Although the airplane’s flap setting was likely 10°, the final seconds of the airplane’s flightpath were consistent with an aerodynamic stall and an entry phase of a spin at an altitude too low to recover. Review of six detailed flight notebooks maintained by the pilot’s wife showed a multi-year history of in-flight notations of the times for every radio call, configuration change, entry in the traffic pattern, and turns within the traffic pattern. Given the failure of the pilot’s wife to note the time of entry into the downwind leg of the traffic pattern and the irregularity of the flightpath that commenced on the downwind leg of the traffic pattern, it is likely that there was a distraction in the cockpit around this time; however, the reason for the distraction could not be determined. The distraction likely led to his failure to lower his landing gear and flight control inputs that allowed the airplane to exceed its critical angle of attack, leading to an aerodynamic stall at low altitude. Review of the pilot’s medical history and medications revealed that the upset was unlikely to have been an effect of any of his medical conditions or his use of fluoxetine.
HISTORY OF FLIGHTOn February 13, 2020, at 1126 eastern standard time, a Mooney M20J, N1149T, was substantially damaged when it was involved in an accident near Bartow Executive Airport (BOW), Bartow, Florida. The pilot and a passenger were fatally injured. The airplane operated under the provisions of Title 14 Code of Federal Regulations Part 91 as a personal formation flight. According to the flight-lead of the four-airplane formation flight, the accident pilot and his wife joined the flight at the last minute and were assigned the No. 4 position that included an RV-9, RV-6A, RV8, and the accident airplane. Review of data from an onboard Stratus device and automatic dependent surveillance-broadcast (ADS-B) data for the lead airplane in the formation flight revealed that the formation flight departed Spruce Creek Airport (7FL6), Daytona Beach, Florida, about 1045. The accident airplane climbed to 1,300 ft then 1,700 ft msl (mean sea level) while maintaining an airspeed between 120 knots and 140 knots during the formation flight to BOW. Throughout the flight, the accident airplane’s path, altitude, and speed closely followed those of the lead airplane. The formation began descending at 1117. Approaching BOW, the BOW air traffic tower controller instructed the formation flight to enter the right downwind leg of the traffic pattern for runway 23. The formation flew about 3 miles northwest of BOW and the flight-lead instructed the other pilots in the formation to “Go extended trail.” According to the flight lead, all complied and were in-trail behind the flight lead to enter the BOW traffic pattern. The last notation in a detailed flight log recovered in the wreckage and kept by the passenger read, “Extended trail 1122.” About this time, the accident airplane’s speed diverged from that of the lead airplane when the accident airplane slowed 30 knots. The accident airplane pilot then turned from a track of 210° to 70° following the three airplanes into the traffic pattern “in trail.” The flight lead stated that he made a short base turn, and it was expected that each airplane would make a later turn onto the base leg than the previous airplane, thereby increasing the spacing between the airplanes. Data from the Stratus device revealed that the accident airplane slowed and descended on the downwind leg. At 1125:18, and about 1,500 ft past the lead airplane’s turn, the accident airplane pilot maneuvered the airplane onto the base leg of the traffic pattern, with the airplane’s bank angle varying between 5° and 20° (see figure 1). From 1125:45 to 1126, the accident airplane leveled off on the base leg at an airspeed of about 70 knots and an altitude of 500 ft mean sea level (msl). Just after 1126, the airplane turned right toward the runway and began to pitch down. The airplane continued its right turn, passing through the runway heading before turning left and steeply descending at 1126:15. The data ended at 1126:19 when the airplane was about 230 ft msl, 110 ft above ground level, and 0.6 nm short of the threshold for runway 23. Figure 1: Lead and accident airplanes' final approach paths A witness working the ground control position at the BOW tower at the time of the accident reported that she looked up from her station and saw airplane No. 1 on short final. Airplanes Nos. 2, 3, and 4 (the accident airplane) were “very close” and also on short final. From her perspective, airplane Nos. 2, 3, and 4 appeared to be in a triangle formation; however, the accident airplane was inverted and descended straight down to the ground. A witness on the ramp at BOW was watching the airplanes on final approach and observed what he thought was a “flight of 3.” When he first observed the airplanes, they were lined up on final approach in trail of each other: airplane No. 1 was ready to touch down, airplane No. 2 was “a few hundred yards” in trail, and airplane No. 3 was over the airport property boundary. He watched airplane No. 1 “land long” then airplane No. 2 “land short.” He then observed the accident airplane approaching airplane No. 3, which was on final approach, from the right at a 30-45° angle. The accident airplane’s right wing “dipped severely attempting to avoid” airplane No. 3, followed by a steep left bank and then a vertical descent to the ground. He stated that the accident airplane was “closing in on airplane No. 3” and made a “sharp right turn to avoid a midair” collision. A second witness at the airport reported a similar account. A dashcam video from a vehicle traveling toward the final approach path of runway 23 captured airplane No. 3 established on final approach and the accident airplane in trail, in a right bank then left bank before it entered a nose down attitude and descended toward the ground. The pilot’s niece stated that her aunt and uncle enjoyed participating in formation flights. She stated that her aunt and uncle were meticulous in their maintenance and planning, and that her aunt kept detailed logs of every flight in a notebook. Review of six of these logs revealed minute by minute entries for every flight that included takeoff time, altitudes, all radio calls with frequencies, every turn within the traffic pattern, unexpected noises, landing times, fuel purchases, and more. One such notebook labelled “Tango Book #7, Nov. 2019” was recovered from the wreckage, and the entries related to the accident flight included: RWY 24 10:45 123.7 10:46 121.2 KBOW T 11:09 Lt 11:10 ~~~~~~~~~~~~~~~~~ 121.2 KBOW T 11:20 Extended Trail 11:22 There were no further log entries, and, unlike log entries from previous flights, there were no entries for the accident flight’s downwind or base legs of the traffic pattern. AIRCRAFT INFORMATIONThe airplane was equipped with an engine monitor that recorded engine speed, horsepower, fuel consumption, outside temperatures and engine temperatures. A review of the extracted data revealed that the accident airplane was fueled 11 days prior to the accident flight and contained about 16 gallons of fuel at the time of the accident. Review of the recorded engine data revealed normal engine parameters during the flight. According to the FAA’s Airplane Flying Handbook (FAA-H-8083-3C), Chapter 8: Airport Traffic Patterns, “When flying on the downwind leg, the pilot should complete all before-landing checks and extend the landing gear if the airplane is equipped with retractable landing gear.” The airplane was equipped with an electric flap actuator that would change the flap position for as long as the pilot held down the switch and could put the flaps in any position between 0° and 33°. The accident airplane’s Pilot’s Operating Handbook included the following Before Landing Checklist: Seat, Seat Belts and Shoulder Harnesses – ADJUST AND SECURE Internal/External Lights – AS DESIRED Landing Gear –EXTEND BELOW 133 KIAS Mixture Control – FULL RICH Fuel Selector – RIGHT OR LEFT (Fullest tank) Propeller Control – HIGH RPM Wing Flaps – FULL DOWN (33°) BELOW 115 KTS AIRPORT INFORMATIONThe airplane was equipped with an engine monitor that recorded engine speed, horsepower, fuel consumption, outside temperatures and engine temperatures. A review of the extracted data revealed that the accident airplane was fueled 11 days prior to the accident flight and contained about 16 gallons of fuel at the time of the accident. Review of the recorded engine data revealed normal engine parameters during the flight. According to the FAA’s Airplane Flying Handbook (FAA-H-8083-3C), Chapter 8: Airport Traffic Patterns, “When flying on the downwind leg, the pilot should complete all before-landing checks and extend the landing gear if the airplane is equipped with retractable landing gear.” The airplane was equipped with an electric flap actuator that would change the flap position for as long as the pilot held down the switch and could put the flaps in any position between 0° and 33°. The accident airplane’s Pilot’s Operating Handbook included the following Before Landing Checklist: Seat, Seat Belts and Shoulder Harnesses – ADJUST AND SECURE Internal/External Lights – AS DESIRED Landing Gear –EXTEND BELOW 133 KIAS Mixture Control – FULL RICH Fuel Selector – RIGHT OR LEFT (Fullest tank) Propeller Control – HIGH RPM Wing Flaps – FULL DOWN (33°) BELOW 115 KTS WRECKAGE AND IMPACT INFORMATIONAccident Site Examination Examination of the accident site and wreckage revealed that the airplane struck a large tree before impacting terrain at a private residence about .6 nm from runway 23 at BOW. A ground scar associated with the left wing was oriented on a magnetic heading of about 090°, and the fuselage came to rest upright oriented on a magnetic heading of about 046°. Fire rescue personnel and the BOW airport manager arrived at the accident site and reported a faint fuel odor near the engine, which dissipated within minutes. Airframe and Engine Examination All major airplane components were located on site. No preimpact anomalies or malfunctions were identified during the airplane examination that would have prevented normal operation. Flight control continuity was established from the control surfaces to the cockpit area. Both wings were impact-crushed aft, and there was no evidence of fire on any portion of the airplane. The left fuel tank was impact breached. The landing gear was determined to be in the UP position and the flaps were extended to 10°. Examination of the propeller blades revealed one blade was separated from the hub and exhibited leading edge gouges, chordwise scoring and twisting along the longitudinal axis. The other blade exhibited leading and trailing edge gouges and chord-wise scoring. The engine and its accessories were examined. The engine was rotated using a tool inserted in the vacuum pump drive pad. Continuity of the crankshaft to the rear gears and to the valve train was confirmed. Compression and suction were observed from all four cylinders. The left and right magnetos were removed, and sparks were observed on all towers when each magneto was rotated by hand. Examination of the engine’s cylinders with a lighted borescope revealed no anomalies. ADDITIONAL INFORMATIONPerformance Study A performance study was completed based on data from an onboard Stratus device. Groundspeed and calibrated airspeed were calculated using the recorded flight path data and reported weather. A simplified airplane model consisting of lift curve data provided by Mooney International Corporation and airplane geometry was used to calculate airplane pitch, roll, and angle of attack (AoA). Figure 2 shows the calculated AoA of the airplane using the no flaps lift data and the flaps 15° lift data. Also shown is an estimated angle of attack for 10° of flaps assuming a linear relationship between the other flap lift curves. As the airplane slowed and maneuvered on descent, the angle of attack increased. The airplane’s maximum angle of attack occurred at 1126:10 after which it abruptly dropped. The airplane’s descent accelerated from about 500 fpm between 1126 and 1126:12 to more than 1,500 fpm after 1126:12. Figure 3: Accident flight altitude, msl, and calculated angle of attack (AoA) MEDICAL AND PATHOLOGICAL INFORMATIONThe Office of the District Medical Examiner, Winter Haven, Florida, performed the pilot’s autopsy. According to the autopsy report, the pilot’s cause of death was blunt impact, and the manner of death was accident. The autopsy identified pulmonary emphysema and a fatty liver. Toxicology testing performed by the FAA’s Forensic Sciences Laboratory identified fluoxetine and its metabolite norfluoxetine in the pilot’s liver and urine. Fluoxetine is an antidepressant often marketed with the name Prozac. It carries this warning, “As with any central-nervous-system-active drug, fluoxetine has the potential to impair judgment, thinking, or motor skills. Patients should be cautioned about operating hazardous machinery, including automobiles, until they are reasonably certain that the drug treatment does not affect them adversely.” Personal medical records were obtained from the pilot’s regular physician. According to these records, the pilot had a history of depression and was intermittently treated with fluoxetine. At the last visit, 4 months before the accident, the physician noted he was not currently taking the medication and was feeling in good spirits. In addition, he had a diagnosis of high cholesterol, for which he as taking atorvastatin.
The pilot’s exceedance of the airplane's critical angle of attack and subsequent aerodynamic stall and spin at low altitude due to a possible distraction in the cockpit for which the reason was undetermined.
Source: NTSB Aviation Accident Database
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