Accident Details
Probable Cause and Findings
The student pilot’s exceedance of the critical angle of attack during a go-around, resulting in an aerodynamic stall and impact with terrain following a non-stabilized approach to land.
Aircraft Information
Registered Owner (Current)
Analysis
HISTORY OF FLIGHTOn November 5, 2022, about 1200 Pacific daylight time, a Cirrus SR20, N700YZ, was substantially damaged when it was involved in an accident near San Diego, California. The student pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight.
The student pilot was on a solo flight conducting pattern work at Montgomery-Gibbs Executive Airport (MYF), San Diego, California.
Witnesses located at the airport reported that they observed the airplane overfly the runway at a low altitude and high rate of speed. While over the runway, the airplane made several pitch up and down oscillations. When the airplane reached the departure end of the runway, it pitched up and entered into what looked like a high-speed departure stall and descended in a nose-down, right-wing low attitude toward the ground.
A review of MYF's air traffic control recordings revealed that there were two other airplanes taking off from RWY 28R ahead of the accident airplane landing. After the second airplane departed, about 14 seconds later, the tower controller instructed the accident airplane, who was on a one-mile final, to sidestep to the left and go around for spacing. There was no response from the pilot and the tower controller repeated the go-around instructions; again, there was no response. During this time, a radio transmission was heard on frequency about a trim problem; the transmission was believed to be from the accident pilot. The tower controller transmitted that someone had a stuck mic on the tower frequency.
Recorded automatic dependent surveillance-broadcast (ADS-B) data provided by the Federal Aviation Administration (FAA) showed the accident airplane conducting traffic pattern work to both runways 28L and 28R at MYF. The pilot flew 2 turns in the pattern to RWY 28L (left traffic), followed by 2 turns in the pattern to RWY 28R, the second of which was the accident leg, as seen in Figure 1. The data showed that at 1155:58 the airplane continued to descend in a right turn until ADS-B contact was lost, about 350 ft southeast of the accident site.
Figure 1. View of accident airplane ADS-B flight track data.
The flight school operator provided a video that showed the accident airplane on final approach to land and flare over the runway. The airplane continued over the runway, with a series of pitch up and down oscillations. When the airplane was near the departure end of the runway, it entered into a climbing right turn and is lost from the video camera’s view. PERSONNEL INFORMATIONThe student pilot accumulated about 64 total hours of flight experience in the accident airplane make and model, which included dual instruction with a flight instructor. AIRCRAFT INFORMATIONThe airplane was equipped with the Garmin Electronic Stability and Protection (ESP) system. According to the manufacturer, the system is designed to provide automatic control inputs to discourage airplane operation outside the normal flight envelope. The system works to maintain the desired pitch, roll, and airspeed operating envelope by automatically engaging one or more servos when the airplane is near a defined pitch, roll, and/or airspeed operating limit, and the ESP system engages when there is an exceedance in one or more of the conditions beyond the normal flight parameters. This is perceived by the pilot as a resistance to flight control movement in the undesired direction when the airplane approaches a steep attitude or high airspeed. Roll limit indicators are displayed on the roll scale at 45° right and left, indicating where ESP will engage. As roll attitude exceeds 45°, the ESP system will engage, and the on-side Roll Limit Indicator will move to 30° and will disengage as roll attitude decreases.
The airplane was equipped with a recoverable data module (RDM) that recorded flight, engine, and autopilot parameters in one-second intervals. A review of the data showed that about 1153:00 the airplane was on the right downwind leg of the traffic pattern for runway 28R, with a GPS altitude of 1,422 ft, about 1,000 ft above ground level (agl). About 1153:27, the flap switch was at the 50% position, and the airplane entered a right descending turn consistent with a downwind to base turn. At 1153:52, the flap switch indicated the 100% position, and the airplane continued a right descending turn consistent with a base to final turn. From 1154:39 throughout the remaining recorded data, pitch changes were observed alternating from 20° pitch up to -30° pitch down. The recorded data showed that, at 1154:55, the flap switch changed from the 100% position to the 50% position, with a recorded indicated airspeed of 106 knots. The flap switch indicated the 50% position for the remainder of the flight. The airplane continued to descend to a GPS altitude of 434 ft, and the indicated airspeed increased over the next 53 seconds, reaching a maximum of 140 knots. The recorded data showed that at 1155:55, with a recorded indicated air speed of 125 knots, 20° pitch up attitude, and 13° bank, the airplane entered a steep right roll, the ESP system activated in roll mode as the airplane exceeded a 20° pitch down attitude and 70° bank, the stall warning indicated, and the recording ended at 1156:00, as seen in Figure 2.
Figure 2. View of RDM flight track data. AIRPORT INFORMATIONThe airplane was equipped with the Garmin Electronic Stability and Protection (ESP) system. According to the manufacturer, the system is designed to provide automatic control inputs to discourage airplane operation outside the normal flight envelope. The system works to maintain the desired pitch, roll, and airspeed operating envelope by automatically engaging one or more servos when the airplane is near a defined pitch, roll, and/or airspeed operating limit, and the ESP system engages when there is an exceedance in one or more of the conditions beyond the normal flight parameters. This is perceived by the pilot as a resistance to flight control movement in the undesired direction when the airplane approaches a steep attitude or high airspeed. Roll limit indicators are displayed on the roll scale at 45° right and left, indicating where ESP will engage. As roll attitude exceeds 45°, the ESP system will engage, and the on-side Roll Limit Indicator will move to 30° and will disengage as roll attitude decreases.
The airplane was equipped with a recoverable data module (RDM) that recorded flight, engine, and autopilot parameters in one-second intervals. A review of the data showed that about 1153:00 the airplane was on the right downwind leg of the traffic pattern for runway 28R, with a GPS altitude of 1,422 ft, about 1,000 ft above ground level (agl). About 1153:27, the flap switch was at the 50% position, and the airplane entered a right descending turn consistent with a downwind to base turn. At 1153:52, the flap switch indicated the 100% position, and the airplane continued a right descending turn consistent with a base to final turn. From 1154:39 throughout the remaining recorded data, pitch changes were observed alternating from 20° pitch up to -30° pitch down. The recorded data showed that, at 1154:55, the flap switch changed from the 100% position to the 50% position, with a recorded indicated airspeed of 106 knots. The flap switch indicated the 50% position for the remainder of the flight. The airplane continued to descend to a GPS altitude of 434 ft, and the indicated airspeed increased over the next 53 seconds, reaching a maximum of 140 knots. The recorded data showed that at 1155:55, with a recorded indicated air speed of 125 knots, 20° pitch up attitude, and 13° bank, the airplane entered a steep right roll, the ESP system activated in roll mode as the airplane exceeded a 20° pitch down attitude and 70° bank, the stall warning indicated, and the recording ended at 1156:00, as seen in Figure 2.
Figure 2. View of RDM flight track data. WRECKAGE AND IMPACT INFORMATIONExamination of the accident site revealed that the airplane impacted flat open terrain about 730 ft northwest of the departure end of runway 28R. The airplane came to rest upright on a heading of about 10° magnetic, at an altitude of 417 ft mean sea level. The first identified point of contact with terrain was a ground scar/impression on a heading of 195° magnetic and about 125 ft south of the main wreckage. The ground scar/impression was about 11 ft long, 12 inches wide, and 2 inches deep. The debris field was about 125 ft in length and 75 ft wide. Numerous pieces of composite wing, plexiglass, and propeller were observed throughout the debris path.
Flight control continuity was established from the cockpit to all primary flight controls. Numerous separations were noted within the flight control system with signatures consistent with overload separation or due to the recovery process.
Postaccident examination of the recovered airframe and engine did not reveal evidence of any mechanical anomalies that would have precluded normal operation. ADDITIONAL INFORMATIONThe FAA publication H-8083-3C, Airplane Flying Handbook, Use of Flaps, “The increased camber from flap deflection increases lift, primarily on the rear portion of the wing. This produces a nose-down pitching moment which may cause the airplane to pitch down. Flap deployment may also affect wing downwash on the horizontal tail and alter the tail-down force. Consequently, pitch behavior from flap extension depends on the design of the particular airplane.”
The FAA publication H-8083-25A, Pilot's Handbook of Aeronautical Knowledge, stated that an aerodynamic stall results from a rapid decrease in lift caused by the separation of airflow from the wing's surface brought on by exceeding the critical angle of attack (AOA). AOA is defined as the acute angle between the chord line of the airfoil and the direction of the relative wind. An aerodynamic stall can occur when the airplane flies too slowl...
Data Source
Data provided by the National Transportation Safety Board (NTSB). For more information on this event, visit the NTSB Records Search website. NTSB# WPR23FA027