N587CDCirrus Design SR22 · 2005

On April 24, 2021, about 1312 central daylight time, a Cirrus SR-22 airplane, N587CD, was destroyed when it was involved in an accident near Port Aransas, Texas. The pilot was fatally injured, and the two passengers sustained serious injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.

The local flight departed from Mustang Beach Airport (RAS), Port Aransas, as a Young Eagles flight sponsored by the Experimental Aircraft Association (EAA). The Young Eagles event consisted of about eight volunteer pilots who offered children and parents a discovery flight to introduce the children to aviation.

The Young Eagles volunteer pilots were provided with a suggested flightpath for runway 30 departures. The procedure called for a right turn at 500 ft after takeoff and to visually fly along the Corpus Christi ship channel until reaching the municipal harbor. The procedure then called for a left turn toward a lighthouse then a right turn to fly along the beach southbound. The procedure finally called for two right turns to enter back into a right downwind traffic patter to runway 30.

On the morning of the accident, the pilot flew the airplane to RAS and arrived about 1042. At 1153, the pilot departed runway 30 for his first Young Eagles flight. According to witness and air traffic information, the accident pilot made three approaches to runway 12 before landing on runway 12 at 1221 (see figure 1). At 1215, the wind was reported from 140° at 6 knots.

Figure 1. Ground track of first Young Eagles flight

During the second flight of the day, the pilot took a child and the child’s father for their discovery flight. The child sat in the aft right seat, and the father was seated in the front right seat.

The accident flight departed runway 30 about 1305; however, the airplane’s flight track did not follow the suggested route for the event for reasons that could not be determined (see figure 2).

Figure 2. Ground track of accident flight

Witnesses stated that the airplane was “low and slow” on the approach to runway 30, and the airplane almost touched down short of the runway. Before landing, the pilot appeared to initiate a go-around; the engine power increased, the airplane’s nose pitched up sharply, the left wing dropped, the engine power decreased, and the airplane impacted the ground inverted in a nose low angle in front of a row of hangers adjacent to the runway. After ground impact, the Cirrus Airframe Parachute System deployed, and the airplane was destroyed during the impact sequence.

A cell phone video recorded by the front-seat passenger captured the accident flight and impact sequence. About 8 seconds before the impact, the video showed the flap selector switch in the UP (0%) position. About 5 seconds before the impact, the video and audio captured an increase in engine rpm, followed by a left roll, an immediate decrease in engine rpm, and terrain impact in a left-wing low attitude.

According to the pilot’s logbook, the pilot began his flight training on July 7, 2018, and received his private pilot certificate on March 8, 2019. Most of his flight training was conducted in a Cessna C-172 airplane; his last month of training and practical exam (12.8 hours total) were completed in a Piper PA-28. Upon completion of his private certification, the pilot had a total of 99.8 hours of flight time. He started to fly the accident airplane 3 days after he received his private pilot certificate and had a total of 72.5 hours in the accident airplane as of March 6, 2021.

The pilot received flight training in the accident airplane between November 16, 2019, and December 15, 2019, logging 17.3 hours of dual instruction and 19 hours of ground instruction.

The airplane was equipped with an electro-pneumatic stall warning system to provide audible warning of an approach to aerodynamic stall. The system is designed to sound the warning at approximately 5 knots above stall with full flaps and power off in wings level flight and at slightly greater margins in turning and accelerated flight.

According to page 4-21 in the Pilot’s Operating Handbook and Federal Aviation Administration (FAA)-approved Airplane Flight Manual, dated October 10, 2003, both power-on and power-off approaches to landing are conducted with full flaps. The handbook also provided the following caution, in part:

Landings should be made with full flaps. Landings with less than full flaps are recommended only if the flaps fail to deploy or to extend the aircraft’s glide distance due to engine malfunction. Landings with flaps at 50% or 0%; power should be used to achieve a normal glidepath and low descent rate. Flare should be minimized.

For a balked landing (go-around) climb, the handbook stated that the pilot was to “disengage the autopilot (if installed), apply full power, then reduce the flap setting to 50%. If obstacles must be cleared during the go-around, climb at 75-80 knots indicated airspeed with 50% flaps. After clearing any obstacles, retract the flaps and accelerate to the normal flaps-up climb speed.”

The airplane was equipped with an electro-pneumatic stall warning system to provide audible warning of an approach to aerodynamic stall. The system is designed to sound the warning at approximately 5 knots above stall with full flaps and power off in wings level flight and at slightly greater margins in turning and accelerated flight.

According to page 4-21 in the Pilot’s Operating Handbook and Federal Aviation Administration (FAA)-approved Airplane Flight Manual, dated October 10, 2003, both power-on and power-off approaches to landing are conducted with full flaps. The handbook also provided the following caution, in part:

Landings should be made with full flaps. Landings with less than full flaps are recommended only if the flaps fail to deploy or to extend the aircraft’s glide distance due to engine malfunction. Landings with flaps at 50% or 0%; power should be used to achieve a normal glidepath and low descent rate. Flare should be minimized.

For a balked landing (go-around) climb, the handbook stated that the pilot was to “disengage the autopilot (if installed), apply full power, then reduce the flap setting to 50%. If obstacles must be cleared during the go-around, climb at 75-80 knots indicated airspeed with 50% flaps. After clearing any obstacles, retract the flaps and accelerate to the normal flaps-up climb speed.”

The initial impact point was located about 80 ft left of the runway centerline, and the main wreckage came to rest about 90 ft west of the initial impact. Fragmented fiberglass fuselage components and the nose wheel were located between the initial impact and main wreckage.

The main wreckage comprised the engine, cockpit/cabin, both wings, and the empennage. The upper cockpit and cabin structure was destroyed by impact and rescue efforts. The CAPS parachute canopy and suspension lines were deployed and came to rest on the ground adjacent to the main wreckage. The CAPS activation T-handle was found stowed in its receptacle. The outboard left- and right-wing leading edges were crushed aft and wing skin was partially delaminated.

Flight control continuity was established from all flight control surfaces to their respective cockpit controls. The wing flap actuator position was consistent with the flaps in the retracted position. No evidence of any preimpact mechanical malfunctions or failures were noted with airplane that would have precluded normal operation.

The Avidyne primary flight display (PFD) and multifunction display (MFD) units were recovered and sent to the National Transportation Safety Board Vehicle Recorders laboratory for data extraction. The PFD sustained impact damage; however, the two internal nonvolatile memory chips were undamaged. The PFD recording contained records of 68 power cycles, to include the accident flight that was about 14 minutes in duration. The MFD compact flash card was recovered and in good condition. The data were downloaded, and the card contained 124 data files from December 14, 2019, through April 24, 2019, to include the accident flight that was about 14 minutes in duration.

The data downloaded from the PFD showed that just prior to the accident, the airplane’s nose pitched to about 22o, as the airplane rolled to the left and then descended rapidly with a pitch of 30o nose down. The airspeed at the time the data ended was 71 knots. The left roll continued until the data ended.

Stalls

According to page 4-10 in the FAA Airplane Flying Handbook (FAA-H-8083-3B, dated 2016), at the same gross weight, airplane configuration, and power setting, a given airplane will consistently stall at the same indicated airspeed if no acceleration is involved. The airplane will, however, stall at a higher indicated airspeed when excessive maneuvering loads are imposed by steep turns, pull-ups, or other abrupt changes in its flightpath. Stalls entered from such flight situations are called “accelerated maneuver stall,” a term which had no reference to the airspeeds involved. Stalls which result from abrupt maneuvers tended to be more rapid, or severe, than unaccelerated stalls, and because they occur at higher-than-normal airspeeds, and/or may occur at lower than anticipated pitch attitudes, they may be unexpected by an inexperienced pilot. Failure to take immediate steps toward recovery when an accelerated stall occurred may result in a complete loss of flight control, notably power-on spins.

An accelerated stall may be encountered any time excessive back-elevator pressure is applied and/or angle of attack is increased too rapidly.

P-Factor, Torque, and Slipstream Effects

The FAA Pilot’s Handbook of Aeronautical Knowledge also states that an airplane is subject to multiple left-turning tendencies in flight, which include:

- P-Factor - A tendency for an aircraft to yaw to the left due to the descending propeller blade on the right producing more thrust than the ascending blade on the left (clockwise rotation of the propeller as seen from the cockpit). This occurs when the aircraft’s longitudinal axis is in a climbing attitude in relation to the relative wind.

- Torque - In an airplane, the tendency of the aircraft to turn (roll) in the opposite direction

of rotation of the engine and propeller.

- Spiraling slipstream - The slipstream of a propeller-driven airplane rotates around the airplane. This slipstream strikes the left side of the vertical fin, causing the aircraft to yaw slightly. Rudder offset is sometimes used by aircraft designers to counteract this tendency.

- Corkscrew Effect - The high-speed rotation of an aircraft propeller gives a corkscrew or spiraling rotation to the slipstream. At high propeller speeds and low forward speed (as in the takeoffs and approaches to power-on stalls), this spiraling rotation is very compact and exerts a strong sideward force on the aircraft’s vertical tail surface.

- Gyroscopic precession. An inherent quality of rotating bodies, which causes an applied force to be manifested 90° in the direction of rotation from the point where the force is applied.

With an AOA just under the AOA which may cause an aerodynamic buffet or stall warning, the flight controls are less effective. The elevator control is less responsive and larger control movements are necessary to retain control of the airplane. In propeller-driven airplanes, torque, slipstream effect, and P-factor may produce a strong left yaw, which requires right rudder input to maintain coordinated flight. The closer the airplane is to the 1G stall, the greater the amount of right rudder pressure is required.

The Office of the Medical Examiner, Corpus Christi, Texas, performed an autopsy on the pilot. The autopsy listed the cause of death as “multiple blunt force injuries.”

Toxicology testing performed at the FAA Forensic Sciences Laboratory found 20 (mg/dL, mg/hg) of ethanol in the pilot’s blood; no ethanol was detected in the pilot’s urine; 6 (mg/dL) of glucose in the urine; and no drugs of abuse were detected in the blood. Contamination of the specimen by gastrointestinal tract contents can lead to fermentation, which could cause a spurious body cavity blood alcohol result. The absence of alcohol in urine does not rule in or rule out alcohol consumption. Ideally, samples from other organs would be available for comparison. Under these circumstances, it is more likely than not that these results were due to postmortem artifact.