What happened
On March 25, 2024, a Mooney M20K, registration N4387W, departed Northeast Florida Regional Airport (SGJ) in St. Augustine, Florida, bound for Homestead, Florida. Shortly after takeoff, the pilot notified air traffic control that a cabin door had "popped open" and stated the intention to return to the airport. The controller cleared the aircraft for a landing on runway 13.
While performing the return flight, ADS-B data and security camera footage showed the aircraft on the left base leg of the traffic pattern. During this phase, the airplane entered a steep, nose-down descent while rolling to the right. The aircraft impacted a tree and the terrain in a wooded area approximately 1.24 nautical miles northwest of the runway 13 approach end. The pilot and passenger sustained 2 fatal injuries.
The investigation
Investigators examined the wreckage and found the airframe sustained substantial damage to the fuselage and both wings. The engine and its components, including the fuel system, magnetos, and turbocharger, showed no mechanical failures that would have prevented normal operation. An engine monitor recorded that at the time the data recording ended, engine parameters were consistent with a high power setting.
Examination of the aircraft doors revealed that while the baggage door was closed and latched, the main cabin door's upper and aft center latch components showed no damage, indicating the door was likely not properly closed and latched prior to takeoff. The investigation also noted that the pilot's recent flight history included a previous accident involving an aerodynamic stall.
Findings
Analysis of the flight data and wreckage led to the following conclusions:
- The aircraft entered an aerodynamic stall/spin while in the traffic pattern.
- The pilot's attention was diverted by the in-flight opening of the main cabin door.
- The aircraft was at a low altitude during the stall/spin, making recovery unlikely even if proper procedures had been followed.
- The engine monitor data suggests the pilot applied full power in an attempt to recover, whereas the Pilot's Operating Handbook (POH) prescribes reducing the throttle to idle for spin recovery.
- The main cabin door was not properly secured before takeoff.