“A Door Popped Open”: How N4387W Entered a Fatal Stall After Takeoff

The Mooney was cleared to return to Runway 13, but its airspeed fell rapidly during the low-altitude pattern.

On March 25, 2024, Mooney M20K N4387W departed St. Augustine, Florida, on a personal flight to Homestead. Less than a minute after takeoff, the pilot reported that a door had “popped open” and said he needed to return. The tower immediately cleared him to land. The aircraft entered the traffic pattern, but its speed fell as it descended through the base leg. Within roughly two minutes of the door report, the Mooney entered a steep nose-down descent and struck terrain.

Accident Facts

The Door Problem

The pilot was cleared for takeoff on Runway 13 at about 11:50. Less than a minute later he reported the door opening and requested a return. The controller instructed him to enter either downwind and cleared him to land on Runway 13. When asked whether assistance was needed, the pilot said he simply wanted to land and close the door.

The Airplane Was Already Returning

At 11:52:01, ADS-B showed the Mooney on left downwind at 750 ft and 109 knots. Twenty-one seconds later it was at 825 ft while groundspeed had fallen to 95 knots. At 11:52:40 it began descending through 725 ft at 84 knots. The aircraft was already losing its airspeed margin while still on the downwind leg.

The Base Turn

At 11:52:55, the aircraft turned onto left base at 525 ft and 94 knots. Twelve seconds later it was at 475 ft and 83 knots. By 11:53:20, still on base, it had descended to 375 ft and slowed to 73 knots. That was the last ADS-B return. Security-camera footage showed the aircraft entering a steep, nose-down attitude while rolling right.

The Door Was Not a Flight-Control Emergency

The NTSB examined both the rear baggage door and main cabin door. The rear baggage door showed evidence consistent with being closed and latched at impact. The main cabin door did not show the same latch evidence and was likely not properly closed before takeoff. The POH specifically stated that an open main cabin door would not affect flight characteristics and recommended returning normally or climbing to a safe altitude before attempting to close it in flight.

The Engine Was Working

The engine data monitor continued recording until the final portion of the accident sequence. Its parameters were consistent with normal engine operation and a high power setting. Investigators concluded it was likely that the pilot applied full power during the stall/spin in an attempt to recover. The engine itself was not identified as a cause of the accident.

Why Recovery Was Unlikely

The Mooney POH states that a one-turn spin and recovery can require up to 2,000 ft of altitude. N4387W entered the stall/spin below normal traffic-pattern altitude. Even a correct recovery sequence therefore would have had little chance of succeeding before the aircraft reached the ground.

Pilot Recency

The pilot was 68 and held a commercial certificate with an airplane single-engine-land rating and instrument rating. His logbook showed his previous flight had been the day before, but it lasted less than an hour and included only one landing. The NTSB also recorded that his previous flight before that was in May 2023 and had ended in a separate takeoff accident involving a stall after partial engine power loss.

What the Records Show

The NTSB determined that the pilot failed to maintain adequate airspeed in the traffic pattern, resulting in an aerodynamic stall/spin. The in-flight opening of the main cabin door, caused by incorrect closure before takeoff, distracted the pilot and contributed to the accident.

Conclusion

N4387W had a runway available and a landing clearance within seconds of reporting the open door. The accident developed because the return pattern was flown with decreasing airspeed and very little altitude. The NTSB’s conclusion is precise: the door created the distraction, but inadequate airspeed in the traffic pattern produced the fatal stall/spin.

Sources & Reconstruction Note

• https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/193984/pdf