HISTORY OF FLIGHTOn March 25, 2024, about 1154 eastern daylight time, a Mooney M20K airplane, N4387W, was substantially damaged when it was involved in an accident in St. Augustine, Florida. The commercial pilot and passenger were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The flight departed about 1150 from Northeast Florida Regional Airport (SGJ), St. Augustine, Florida, bound for Miami Homestead General Aviation Airport (X51), Homestead, Florida. According to air traffic control audio communications provided by the FAA, the pilot was in contact with an air traffic controller in the control tower at SGJ and had been cleared for takeoff on runway 13. Less than a minute after being cleared for takeoff, the pilot reported that a door had “popped open” and that they would need to return to the airport. The air traffic controller then instructed him to enter either a right or left downwind and cleared him to land on runway 13, and the pilot acknowledged. The air traffic controller asked if they needed any assistance, and the pilot responded that he just wanted to land and close the door. No further communications occurred between the pilot and the air traffic controller. When the air traffic controller could not reestablish contact with the pilot, he stopped all departures and asked the pilots of aircraft in the vicinity to search for N4387W. The wreckage was then found by an occupant of one of the aircraft conducting the search. According to ADS-B data, during the return to the airport, the airplane was on the left downwind leg of the traffic pattern at 1152:01, reaching a peak ground speed of 109 kts at an altitude of 750 ft above mean sea level (msl). By 1152:22, while still on the left downwind leg, the airplane had climbed to 825 ft msl, with its ground speed decreasing to 95 kts. At 1152:40, the airplane began to descend, reaching 725 ft msl and slowing further to 84 kts. After turning onto the left base leg at 1152:55, the airplane descended to 525 ft msl, and its ground speed increased to 94 kts. Continuing on the left base leg, at 1153:07, the airplane descended to 475 ft msl and slowed to 83 kts. Finally, at 1153:20, still on the left base leg, the airplane descended to 375 ft msl, with its ground speed decreasing to 73 kts. This was the last ADS-B return from the airplane. The accident site was located 78 ft away (measured along the ground) from the last ADS-B return. Video images of the airplane captured by a security camera around the time of the last ADS-B return showed that the airplane descended in a steep, nose-down attitude while rolling to the right. PERSONNEL INFORMATIONAccording to the pilot’s logbook, the pilot’s last flight was the day before the accident and was for less than 1 hour and the pilot recorded only one landing. According to 14 CFR 61.57 a pilot could not act as pilot in command of an aircraft carrying passengers unless the pilot had performed 3 takeoffs and landings in the previous 90 days. The flight prior to that, was May 6, 2023, where the pilot recorded in his logbook “crash on takeoff Rwy 25.” An NTSB investigation was performed, according to the report, the pilot entered an aerodynamic stall after a partial loss of engine power. For additional information refer to NTSB Aviation Investigation Final Report for ERA23LA225. AIRCRAFT INFORMATIONAccording to the Mooney M20K POH, the standard procedure for spin recovery is to apply full rudder opposite the direction of spin, move the control wheel forward of neutral, move the ailerons to neutral, and to retard the throttle to idle. The POH also stated that, when descending to traffic pattern altitude, pilots should maintain a safe margin above stall speed. The POH further stated that stalls at low altitude are extremely critical and that up to 2,000 ft of altitude may be lost in a one-turn spin and recovery. The POH also stated that, if the cabin door is not properly closed “it may come unlatched in flight.” The POH stated that this may occur during or just after takeoff. The POH stated that, if the main cabin door does open, the airplane flight characteristics will not be affected and that the pilot should return to the airport in a normal manner. The POH further stated that, if it is deemed impractical to return to land, the door can be closed in flight after reaching a safe altitude by the following procedures: Airspeed 96 kts indicated airspeed, open the pilot’s window, enter a right sideslip (right bank with left rudder), and pull the door shut and latch. AIRPORT INFORMATIONAccording to the Mooney M20K POH, the standard procedure for spin recovery is to apply full rudder opposite the direction of spin, move the control wheel forward of neutral, move the ailerons to neutral, and to retard the throttle to idle. The POH also stated that, when descending to traffic pattern altitude, pilots should maintain a safe margin above stall speed. The POH further stated that stalls at low altitude are extremely critical and that up to 2,000 ft of altitude may be lost in a one-turn spin and recovery. The POH also stated that, if the cabin door is not properly closed “it may come unlatched in flight.” The POH stated that this may occur during or just after takeoff. The POH stated that, if the main cabin door does open, the airplane flight characteristics will not be affected and that the pilot should return to the airport in a normal manner. The POH further stated that, if it is deemed impractical to return to land, the door can be closed in flight after reaching a safe altitude by the following procedures: Airspeed 96 kts indicated airspeed, open the pilot’s window, enter a right sideslip (right bank with left rudder), and pull the door shut and latch. WRECKAGE AND IMPACT INFORMATIONThe airplane impacted in a wooded area 1.24 nautical miles northwest of the approach end of runway 13. The airplane first impacted a tree and then terrain in a steep, nose-down attitude. There was no indication of fire. The airframe sustained substantial damage to the fuselage and to both wings. About 4 ft of the outboard left wing had separated from the rest of the wing and was located at the accident site. The right wing displayed aft crushing damage. The empennage had partially separated from the rest of the fuselage. Flight control continuity was established between the rudder, elevator, and both ailerons from their respective flight controls to the cockpit. Multiple push/pull rods were found fractured, and all the breaks were consistent with impact damage. The throttle, propeller, and mixture controls were all found in the full forward position, and the magneto switch was found in the “BOTH” position. The emergency locator transmitter (ELT) remained attached to the airframe and to its antenna. The ELT switch was found in the “OFF” position. The airplane was equipped with four fuel tanks (two in each wing). All four fuel tanks were found breached and devoid of fuel. All four fuel caps remained secured to their respective filler ports. The fuel caps were removed and examined; the fuel caps displayed normal operating signatures. The fuel strainer bowl was disassembled and visually examined. The fuel strainer screen contained debris in the screen; however, the screen was not obstructed. The fuel selector valve was not observed. The main cabin door, which was located on the right side of the fuselage, was equipped with two latching mechanisms: one on top (upper) and one at the aft center. The main cabin door remained attached to the fuselage by the forward hinge, and its hold-open arm had separated from the door. (The main cabin door was found open when investigators arrived on scene, but its position before first responder activities was not documented.) The main cabin door’s upper latch and pin were found in the retracted position, and examination revealed that the upper door latch assembly components were undamaged and could be operated normally. The main cabin door’s aft center pin actuating rod was found bent, and the latch handle assembly was fractured, consistent with impact damage to the door. The aft center latch striker plate remained attached to the fuselage and was undamaged, and the aft center door latch pin was capable of normal movement when operated manually. The baggage door was found in the open position and remained attached to the fuselage by its door hinge and hold-open arm. The door latch was found in the latched position, and the door lock was in the locked position. Both baggage door latch pins were in the extended position. Both baggage door latch striker plates remained attached to the fuselage, and both displayed gouging in the direction of the baggage door opening position. The baggage door was placed in the closed position, and a crease consistent with impact deformation in the fuselage skin that also continued into the baggage door was observed. The engine remained partially attached to the airframe through one engine mount, cables, wires, and hoses. The engine and all its components displayed impact damage. The propeller flange had separated from the rest of the crankshaft, and multiple 45° cracks were noted along the remaining portion of the crankshaft; the fracture surface was about 45°. Most of the crankshaft and camshaft were visible through the broken oil sump. The visible portions of the crankshaft, camshaft, connecting rods, and lifters displayed normal operating and lubrication signatures. The cylinders were inspected using a lighted borescope. The pistons, exhaust valves, intake valves, and cylinder walls displayed normal operating and combustion signatures. All the rocker arms, valve springs, and valve stems displayed normal operating and lubrication signatures. The oil filter was cut open, and no metallic debris was observed inside the filter pleats. The fuel pump was removed, and the driveshaft coupling was found to be intact. The fuel pump was disassembled, and the internal components displayed normal operating signatures. The throttle and fuel metering assembly were disassembled, and the internal components displayed normal operating signatures. The fuel manifold valve was disassembled and examined. The manifold valve screen contained fibrous debris but was not blocked. The remaining components displayed normal operating signatures. There was a small amount of fuel consistent with 100LL aviation gasoline in the fuel manifold valve. Testing of a fuel sample using water-finding paste detected no water. All fuel nozzles were removed and found to be clear of obstructions. Both magnetos were removed from the engine, and the driveshafts were noted to be capable of rotation. Both magnetos produced a spark on all their posts in the correct firing order. The top spark plugs were removed for examination, and the bottom spark plugs were examined using a lighted borescope. All the spark plug electrodes displayed normal wear and operating signatures. The turbocharger remained attached to the exhaust and intake system. A significant amount of impacted dirt was found in the turbocharger compressor section. Most of the compressor blades were broken, and the compressor nut was loose. The turbine displayed normal operating signatures and was capable of normal rotation. The wastegate displayed impact damage signatures, and the wastegate actuator had broken free. The wastegate valve was found in the closed position, and the wastegate actuating arm displayed impact damage. The turbocharger controller displayed impact damage signatures, and the oil lines were secured to the controller. The three-blade, constant-speed propeller remained attached to the crankshaft propeller flange; however, the propeller flange had separated from the rest of the crankshaft. All three of the propeller blades remained secured in the hub, and the blades displayed impact damage. One propeller blade displayed aft bending and twisting deformation, and the cambered side displayed polishing and chordwise scratches. Another propeller blade displayed minor aft-bending deformation and polishing of the leading edge and the cambered side. The last propeller blade exhibited aft-bending deformation and chordwise scratches. The propeller governor remained attached to the engine and displayed impact damage. The governor was removed, and the oil screen gasket was noted to be clear of debris. FLIGHT RECORDERSThe airplane was equipped with an engine monitor that was capable of recording and storing data for various engine parameters, including the exhaust gas temperatures (EGT), cylinder head temperatures (CHT), turbo inlet temperature (TIT), oil temperature, and system voltage. The engine monitor recorded the accident flight. About 30 minutes into the data recording, the EGTs, CHTs, and TIT increased to levels consistent with the engine being set to full power. About 1 minute later, the EGTs, CHTs, and TIT dropped slightly but remained at levels consistent with an operating engine. The indications then remained steady for about 2 minutes before they dropped again, followed by a sharp increase in indications to levels consistent with the engine being set to full power. The data recording ended with the indications at levels consistent with the engine still operating at a high power setting. MEDICAL AND PATHOLOGICAL INFORMATIONAn autopsy of the pilot’s remains was conducted by Office of the Medical Examiner, Florida District 23, St. Augustine, Florida. According to the pilot’s autopsy report, his cause of death was blunt force trauma, and his manner of death was accident. Toxicology testing performed by the FAA Forensic Sciences Laboratory on the pilot’s remains did not identify any substances that are generally considered impairing.