Saturday, February 9, 2019

Aerodynamic Stall / Spin: North American SNJ-5 (AT-6D) Texan, N12377, fatal accident occurred April 25, 2018 at Kingsville Naval Air Station (KNQI), Kleberg County, Texas

Steve DeWolf

Steven Kelley DeWolf died doing what he loved, flying his North American SNJ-5 (AT-6D) Texan. Born in France to American bomber pilot Colonel James G. DeWolf and his journalist wife, Frances Ray DeWolf, he was the only star in their universe. The family lived many places around the world, loving the military life and all the travel it involved. They became a very tight-knit group of three. Upon returning to the states, the DeWolfs moved to Dayton, Ohio where Steve's father was stationed. Steve completed high school there in 1971 and following graduation accepted an appointment to the U.S. Naval Academy. He studied at the Academy until his eyesight ended his dream of becoming a Navy pilot. He transferred to the University of Texas after his sophomore year and graduated Phi Beta Kappa in 1975 with highest honors. That fall he entered the University of Texas School of Law, receiving his J.D. with honors in 1978. Steve practiced law in Houston before once again returning to school, this time at Queens' College, University of Cambridge, England. In 1983 he received an LL.M. with honors. Steve did nothing halfway. He practiced law in Southern California until 1988 before returning to his beloved, adopted home state of Texas. In the early 1990s, he received his pilot's license and bought a 1943 Stearman open cockpit biplane. He loved to fly and participated in many airshows. The Stearman had a special place in his heart as it was the type of plane his dad had trained in during WWII. He later bought a more advanced trainer, an SNJ/T-6 Texan, much to his wife's chagrin.  
Charles Pomeroy Skoda

LCDR (ret.) Skoda was an F/A-18 Instructor Pilot and member of the Blue Diamonds squadron out of NAS Lemoore. He served 11 years active duty and 9 years active-reserve. After his active duty service, Charles went on to become a pilot for American Airlines out of Dallas, TX. Following the draw-down of post 9/11, Charles entered the business world and was Director of Leadership for Afterburner, Inc. (2002-2005); Senior Manager of Sales, Marketing and Development for Capitol One Auto Finance (2006-2008); Sr. Vice President of Strategic Operations at Noranda Aluminum Holding Corporation (2009-2014); and Sr. Vice President of Corporate Operations for Brock Group (2015-2016). In 2016, he returned to American Airlines and was an Airbus First Officer based in Miami. 

The National Transportation Safety Board traveled to the scene of this accident.

Additional Participating Entity:

Federal Aviation Administration / Flight Standards District Office; San Antonio, Texas

Aviation Accident Final Report - National Transportation Safety Board:

Investigation Docket - National Transportation Safety Board:

Aviation Accident Data Summary - National Transportation Safety Board:

Location: Kingsville, TX
Accident Number: CEN18FA147
Date & Time: 04/25/2018, 1225 CDT
Registration: N12377
Aircraft Damage: Destroyed
Defining Event: Aerodynamic stall/spin
Injuries: 2 Fatal
Flight Conducted Under: Part 91: General Aviation - Personal 


The private pilot, who was the owner of the vintage military trainer airplane, and a pilot-rated passenger were conducting a right turn just after takeoff, while still over the runway surface. Witnesses reported that the airplane's bank angle exceeded 90° and the highest altitude achieved was 200-300 ft. above ground level. The airplane then descended nose low and impacted a the ground less than 1 minute after takeoff. Radar data indicated that the airplane's average airspeed during the final portion of the flight was 87 mph and the bank angle reached about 56°, which would have resulted in a load factor of about 1.8g. Airplane performance data indicated that the accelerated stall speed at this load factor was about 95 mph, thus it is likely that, during the turn, the airplane exceeded its critical angle of attack and entered an accelerated stall at an altitude too low for the pilot to recover. Postaccident examination of the airplane did not reveal any anomalies that could be attributed to a preimpact mechanical deficiency.

The airplane was equipped with tandem seating and dual flight controls; the owner was seated in the front seat and the passenger was seated in the rear seat. The removable rear cockpit control stick was found outside of the airplane, and it could not be determined if the stick was installed at the time of the accident. No conclusive determination could be made as to which occupant was manipulating the controls during the accident sequence.

The private pilot was using decongestant and allergy medications. Toxicological testing identified diphenhydramine, a sedating antihistamine, at levels that were likely impairing; however, the extent to which this contributed to the accident could not be determined.

Probable Cause and Findings

The National Transportation Safety Board determines the probable cause(s) of this accident to be:
The pilot's failure to maintain airspeed during a steep turn after takeoff, resulting in an exceedance of the airplane's critical angle of attack and a subsequent accelerated stall at an altitude too low for recovery. 


Airspeed - Not attained/maintained (Cause)
Angle of attack - Capability exceeded (Cause)
Altitude - Not attained/maintained

Personnel issues
Aircraft control - Pilot (Cause)

Factual Information

History of Flight

Aerodynamic stall/spin (Defining event)

Uncontrolled descent

Collision with terr/obj (non-CFIT)

On April 25, 2018, about 1225 central daylight time, a North American SNJ 5 airplane, N12377, was destroyed when it impacted terrain shortly after takeoff from Kingsville Naval Air Station (NQI), Kingsville, Texas. The private pilot and pilot-rated passenger were fatally injured. The airplane was registered to and was being operated by the pilot under the provisions of Title 14 Code of Federal Regulations Part 91. Day visual meteorological conditions prevailed in the area, and no flight plan was filed for the personal flight, which was originating at the time of the accident with an intended destination of San Marcos Regional Airport (HYI), San Marcos, Texas.

Air traffic control tower personnel reported that the airplane took off on runway 13R and had requested a right teardrop turn for a departure toward the north. Several witnesses reported seeing the airplane in a steep right bank; some witnesses reporting that the bank angle exceeded 90° and the maximum altitude achieved was 200-300 ft above ground level. The airplane descended nose low and the right bank angle decreased before the airplane impacted the ground between runway 17R/35L and taxiway B just south of the intersection of taxiways B and E (Figure 1.).

Figure 1. Airport diagram showing the layout of Kingsville NAS

Review of radar data showed that the airplane began its takeoff roll from runway 13R at 1224:01. The accident flight was captured in 11 radar returns, with the final return at 1224:52. No altitude data was recorded. The airplane's ground track continued along the runway centerline from the takeoff position for about 2,000 ft before making a slight left turn followed by a right turn. The right turn continued to the end of the data and the final recorded position was about 100 ft east of the initial impact point.Based on the final 3 recorded radar returns, the turn radius was estimated to be about 450 ft and the calculated average groundspeed was 87 mph. Based on this information, the calculated bank angle was about 56° during the final portion of the flight. For a level, 56°-banking turn, the calculated flight load factor was 1.8g. Based on the velocity versus load factor (V-N) diagram for the accident airplane, a load factor of 1.8g equated to an accelerated stall speed about 95 mph. The airplane's ground track is depicted in Figure2.

Figure 2. Overhead view of the airplane's ground track

Pilot Information

Certificate: Private
Age: 64, Male
Airplane Rating(s): Single-engine Land
Seat Occupied: Front
Other Aircraft Rating(s): None
Restraint Used: 4-point
Instrument Rating(s): None
Second Pilot Present: Yes
Instructor Rating(s): None
Toxicology Performed: Yes
Medical Certification: Class 3 With Waivers/Limitations
Last FAA Medical Exam: 04/17/2018
Occupational Pilot: No
Last Flight Review or Equivalent:
Flight Time: 3000 hours (Total, all aircraft)

Pilot-Rated Passenger Information

Certificate: Airline Transport; Commercial
Age: 50, Male
Airplane Rating(s): Multi-engine Land; Single-engine Land
Seat Occupied: Rear
Other Aircraft Rating(s): None
Restraint Used: 4-point
Instrument Rating(s): Airplane
Second Pilot Present: Yes
Instructor Rating(s): None
Toxicology Performed: Yes
Medical Certification: Class 1 Without Waivers/Limitations
Last FAA Medical Exam: 07/18/2017
Occupational Pilot: Yes
Last Flight Review or Equivalent: 
Flight Time: 5000 hours (Total, all aircraft) 

The pilot, age 64, held a private pilot certificate with an airplane single-engine land rating. His most recent Federal Aviation Administration (FAA) third-class medical certificate was issued on April 17, 2018, with a limitation for corrective lenses. On the application for that medical certificate, the pilot reported 3,000 total hours of flight experience, with 40 hours in the previous 6 months. The pilot's flight logbook was not available for review.

The passenger, age 50, held an airline transport pilot certificate with airplane multiengine land and airplane single-engine land ratings. The single-engine rating was limited to commercial pilot privileges. Military records indicated that he had accumulated at least 2,400 hours of flight experience before his discharge from the military. No civilian flight records were reviewed; however, the pilot reported 5,000 total hours of flight experience on the application for his most recent FAA first-class medical certificate, dated July 20, 2017. The medical certificate listed no limitations.

Aircraft and Owner/Operator Information

Registration: N12377
Model/Series: SNJ 5
Aircraft Category: Airplane
Year of Manufacture:
Amateur Built: No
Airworthiness Certificate: Normal
Serial Number: 85086
Landing Gear Type: Retractable - Tailwheel
Seats: 2
Date/Type of Last Inspection: 11/20/2017, Annual
Certified Max Gross Wt.: 5300 lbs
Time Since Last Inspection:
Engines: 1 Reciprocating
Airframe Total Time: 7718 Hours as of last inspection
Engine Manufacturer: Pratt & Whitney
Engine Model/Series: R-1340-AN-1
Registered Owner: On file
Rated Power: 600 hp
Operator: On file
Operating Certificate(s) Held: None

The airplane, serial number 85086, was a single-engine monoplane used to train military pilots during World War II and into the 1970s. It was equipped with retractable conventional (tailwheel) landing gear and tandem seating for two occupants. The airplane was powered by a 600-horsepower Pratt & Whitney R-1340-AN-1 radial reciprocating engine, which drove a 2-blade, constant-speed Hamilton Standard 12D40-6101-12 propeller.

Maintenance records indicated that the most recent annual inspection was completed on November 20, 2017, at an airframe total time of 7,717.7 hours. According to the entry, the engine had accumulated 414.7 hours since its most recent overhaul.

Registration information indicated that the pilot had owned the airplane since 2007. 

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual Conditions
Condition of Light: Day
Observation Facility, Elevation: NQI, 50 ft msl
Distance from Accident Site: 0 Nautical Miles
Observation Time: 1232 CDT
Direction from Accident Site: 0°
Lowest Cloud Condition: Few / 3000 ft agl
Visibility:  10 Miles
Lowest Ceiling: None
Visibility (RVR):
Wind Speed/Gusts: 16 knots / 23 knots
Turbulence Type Forecast/Actual: /
Wind Direction: 120°
Turbulence Severity Forecast/Actual: /
Altimeter Setting: 30.01 inches Hg
Temperature/Dew Point: 31°C / 13°C
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: Kingsville, TX (NQI)
Type of Flight Plan Filed: None
Destination: Austin, TX (HYI)
Type of Clearance: VFR
Departure Time: 1224 CDT
Type of Airspace: Class D 

At 1232, the weather conditions recorded at NQI included wind from 120° at 16 knots gusting to 23 knots, 10 miles visibility, few clouds at 3,000 ft above ground level (agl), temperature 31°C, dew point 13°C, and an altimeter setting of 30.01 inches of mercury. 

Airport Information

Runway Surface Type: Concrete
Airport Elevation: 50 ft
Runway Surface Condition: Dry
Runway Used: 13R
IFR Approach: None
Runway Length/Width: 8000 ft / 200 ft
VFR Approach/Landing: None

Wreckage and Impact Information

Crew Injuries: 1 Fatal
Aircraft Damage: Destroyed
Passenger Injuries: 1 Fatal
Aircraft Fire: On-Ground
Ground Injuries: N/A
Aircraft Explosion: On-Ground
Total Injuries: 2 Fatal
Latitude, Longitude: 27.503889, -97.812222

The initial impact point was in a grass area about 1,200 ft right of the runway 13R centerline and about 3,500 ft from its approach end. Most of the wreckage came to rest on the ramp near taxiway E. The debris path was oriented in a westerly direction with the first impact mark about 20 ft from the east edge of the paved ramp area.

The engine separated from the fuselage and the supercharger section of the engine separated from the cylinder section. The propeller remained attached to the engine with one blade intact, displaying evidence of chordwise scratching on the cambered side and twisting of the outboard portion of the blade toward low pitch. The other blade was missing the outboard 2 ft, which came to rest near the ground scar. There was a propeller slash in the dirt and the broken section of the blade displayed leading edge gouging, chordwise scratching, and bending.

Both wings separated upon impact. The right wing came to rest at the east edge of taxiway B. The fuselage came to rest on its right side about 30 ft west of the right wing. The left wing came to rest about 100 ft further west.

The wing was composed of 3 sections; a center section and 2 outboard wing panels. The right wing and a portion of the center section came to rest upright between the initial impact point and the fuselage. The right portion of the wing center section was crushed and twisted and remained attached to the outboard right wing panel. The outboard portion of the wing panel displayed fire damage and upward bending of the portion outboard of the wing joint. The flap remained attached to the outboard portion of the wing. The inboard portion of the right aileron remained attached to the wing.

The left wing separated at the joint and came to rest upright. The aileron was separated, but the inboard portion was found between the fuselage and left wing. The flap remained attached. The left wing was predominately intact. There was aft, angular crushing damage to the wing tip from the tip to about 3 ft inboard. The leading edge inboard of this damage was intact and showed little deformation.

The fuselage was mostly intact. The steel tube fuselage structure at the firewall was bent aft with more significant bending of the right side of the firewall. The firewall crush angle was indicative of about a 30° right-wing-low impact. The left horizontal stabilizer, elevator, vertical stabilizer, and rudder remained attached. The right horizontal stabilizer and elevator remained attached and were bent upward about 90°.

Flight control continuity was established from the forward cockpit rudder pedals aft to the rudder. The left pushrod connecting the forward and aft cockpit rudder pedals were intact but bent about mid-length. The right rudder interconnect pushrod was broken in two; the forward and aft portions remained attached to their respective rudder pedals. Elevator control continuity was established for the complete cable circuit from the elevator forward to the forward control stick bellcrank, then forward around the firewall-mounted pulley and aft to the elevator. Pulling on the rudder and elevator cables resulted in corresponding movement of the respective surfaces. The aileron control bellcrank remained attached and intact on the torque tube with the aileron control cables still attached to the bellcrank. One cable was about 3 ft long, and the other was about 6 inches long to their respective separation points. Both separations were consistent with overload failure. Aileron control cable continuity within the wings was established through several breaks consistent with overload failure.

The forward cockpit control stick casting was fractured from the torque tube and the stick was fractured from its mount. The removable rear cockpit control stick was found lying on the ramp adjacent to the airplane. Examination could not confirm if the stick had been installed in its socket prior to impact.

The right landing gear remained attached to the wing. The left landing gear was broken loose and came to rest between the fuselage and the left wing.

Examination of the airplane did not reveal any evidence of preimpact mechanical failures or anomalies.

Medical And Pathological Information


On his medical certificate application, the pilot reported his use of tamsulosin to treat benign prostate hypertrophy and allopurinol for gout. These medications are generally not considered to be impairing. The pilot reported no other medical conditions or medications.

The Nueces County Medical Examiner, Corpus Christi, Texas, performed an autopsy of the pilot. The cause of death was blunt force trauma. The pilot had moderate to severe coronary artery disease with up to 60% narrowing of the right coronary and 70% narrowing of the left coronary artery. No other significant natural disease was identified.

National Medical Services Laboratory (NMS Labs) testing of cavity blood conducted as part of the autopsy was negative for alcohol and carbon monoxide. Testing detected diphenhydramine at 160 ng/ml; pseudoephedrine at 120 ng/ml, and its metabolite, norpseudoephedrine, at 12 ng/ml; and caffeine.

The FAA Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma, performed toxicology testing on specimens of the pilot. Diphenhydramine was detected in urine and at 156 ng/ml in cavity blood; pseudoephedrine was detected in blood and urine; and tamsulosin was detected in cavity blood and urine.

Pseudoephedrine, caffeine, and tamsulosin are generally not considered to be impairing. Diphenhydramine is a sedating antihistamine used to treat allergy symptoms and as a sleep aid. It is available over the counter under the trade names Benadryl and Unisom. The therapeutic range for diphenhydramine is 25.0 to 112.0 ng/ml. Blood concentrations following a single dose of 50 mg diphenhydramine in 10 healthy adults produced an average peak plasma concentration of 66 ng/ml at 2.3 hours. Further, in a driving simulator study, a single 50 mg dose of diphenhydramine impaired driving ability more than a blood alcohol concentration of 0.100%. Diphenhydramine carries the FDA warning, "may impair mental and/or physical ability required for the performance of potentially hazardous tasks (e.g., driving, operating heavy machinery)." Compared to other antihistamines, diphenhydramine causes marked sedation; this is the rationale for its use as a sleep aid. Altered mood and impaired cognitive and psychomotor performance may also be observed.

Diphenhydramine undergoes postmortem redistribution where, after death, the drug can leach from storage sites back into blood. Central postmortem blood levels may be about two to three times higher than peripheral levels.

Pilot-Rated Passenger

The pilot-rated passenger reported no medications and had no significant medical conditions during his most recent FAA medical examination.

The Nueces County Medical Examiner's autopsy documented the cause of death as multiple crush injuries. The passenger had moderate coronary artery disease with up to 50% narrowing of the right coronary, 40% narrowing of the left coronary, and 30% narrowing of the circumflex coronary arteries. No other significant natural disease was identified.

NMS Labs forensic toxicology testing of femoral blood conducted as part of the autopsy was negative for alcohol, carbon monoxide, and tested-for drugs.

FAA Bioaeronautical Sciences Research Laboratory toxicology testing detected no carbon monoxide in femoral blood, no ethanol in vitreous, and no tested-for-drugs in urine.

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