Thursday, May 14, 2020

Flight Control System Malfunction/Failure: Titan Tornado S, N318WH; accident occurred May 09, 2020 near Haskell Airport (2K9), Oklahoma

Aviation Accident Final Report - National Transportation Safety Board

The National Transportation Safety Board did not travel to the scene of this accident.

Additional Participating Entity:
Federal Aviation Administration / Flight Standards District Office; Oklahoma City, Oklahoma

Investigation Docket - National Transportation Safety Board:

Location: Haskell, Oklahoma 
Accident Number: CEN20LA173
Date & Time: May 9, 2020, 06:45 Local
Registration: N318WH
Aircraft: Titan TITAN TORNADO S 
Aircraft Damage: Substantial
Defining Event: Flight control sys malf/fail 
Injuries: 1 Serious
Flight Conducted Under: Part 91: General aviation - Flight test


The student pilot departed on a flight in a kit-built airplane to test the winglets he had recently installed on the airplane’s stabilator, which were intended to eliminate the airplane’s uncommanded yaw. The flight was the airplane's first winglet test flight away from the airport traffic pattern and at a higher altitude. The student stated that during the flight, he decreased the pitch attitude to level off at 2,000 ft above ground level and the airplane suddenly vibrated aggressively and it "felt like the tail was thumping." He decreased the engine power, but the thumping and vibrating continued, so the pilot pitched the airplane down for an off-field emergency landing. Before he was able to land, the airplane rolled inverted and descended into the trees, resulting in the separation of the right wing.

Postaccident examination revealed that the stabilator control horn had fractured due to overstress and separated from the push-pull tube. According to an airplane kit manufacturer engineer, winglets added to the stabilator produce flutter. Based on the evidence, it is likely that the winglets led the stabilator to flutter, which overstressed the stabilator control horn and resulted in the control horn’s failure.

Probable Cause and Findings

The National Transportation Safety Board determines the probable cause(s) of this accident to be:
The student pilot/builder’s addition of winglets to the stabilator, which resulted in flutter and overstress failure of the stabilator control horn.


Aircraft Horizontal stabilizer - Capability exceeded
Aircraft Horiz stab misc structure - Design
Personnel issues Modification/alteration - Student/instructed pilot
Aircraft (general) - Attain/maintain not possible
Personnel issues Aircraft control - Student/instructed pilot

Factual Information

On May 9, 2020, about 0645 central daylight time, an experimental Titan Tornado S airplane, N318WH, was substantially damaged when it was involved in an accident about 3 miles north of Haskell Airport (2K9), Haskell, Oklahoma. The pilot sustained serious injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 test flight.

The student pilot stated that the airplane had experienced uncommanded yaw on previously flights which he was trying to eliminate. After some research and a conversation with the airplane kit manufacturer, he installed vortex generators. The vortex generators did not eliminate the yaw, so he installed makeshift winglets on the stabilator, which were made from ½ inch plywood and aircraft speed
tape. He did not ask the airplane kit manufacturer about the use of winglets on the stabilator, nor was he required to.

The student pilot conducted a test flight with the makeshift winglets and the uncommanded yaw was eliminated. Since the winglets proved successful, he created new winglets out of composite material, then attached them to the stabilator with glue and rivets. He completed 3 to 4 test flights with the new winglets and remained in the traffic pattern for all of the test flights. The airplane maintenance logbooks did not contain any entry for the winglets because the pilot was still conducting test flights and was not ready to have a mechanic sign off on the installation.

The student pilot stated that on the morning of the accident, he intended to complete the first winglet test flight away from the airport and at a higher altitude than the other test flights. He departed from 2K9 and climbed about 600 feet per minute to 2,000 ft where he intended to level off. He stated that the airplane flew really well with no anomalies noted at that point. As he decreased the pitch attitude, the airplane suddenly vibrated aggressively and it "felt like the tail was thumping." He decreased the engine power to slow the airplane down and descend in altitude, but the thumping and vibrating continued. He pitched the airplane down for an off-field emergency landing. Before he was able to land, the airplane rolled inverted and descended into the trees.

The responding Federal Aviation Administration (FAA) inspector stated that the airplane was found in a densely wooded area with the right wing separated and significant impact damage to the entire airplane. The stabilator control horn was found fractured and disconnected from the push-pull tube.

A postaccident examination of the stabilator control horn revealed that it fractured due to overstress from gross mechanical deformation. The part also exhibited impact damage from the stabilator being actuated from control stop to control stop during the flight.

The airplane kit manufacturer engineer stated that winglets added to the stabilator would change the balance of the control surface and cause flutter. The stabilator is installed with a counterweight calibrated specifically for the stock stabilator. He had never seen anyone add winglets to the stabilator before and he hoped that a builder would contact him before adding winglets. He would tell a builder not to add winglets because it would alter the balance on the control surface.

History of Flight

Enroute-climb to cruise Flight control sys malf/fail (Defining event)
Emergency descent Loss of control in flight
Uncontrolled descent Collision with terr/obj (non-CFIT)

Pilot Information

Certificate: Student 
Age: 33, Male
Airplane Rating(s): Single-engine land
Seat Occupied: Front
Other Aircraft Rating(s): None
Restraint Used: Unknown
Instrument Rating(s): None
Second Pilot Present: No
Instructor Rating(s): None 
Toxicology Performed: No
Medical Certification: None None 
Last FAA Medical Exam: June 18, 2019
Occupational Pilot: No
Last Flight Review or Equivalent:
Flight Time: 162.3 hours (Total, all aircraft), 33 hours (Total, this make and model)

Aircraft and Owner/Operator Information

Aircraft Make: Titan
Registration: N318WH
Model/Series: TITAN TORNADO S Undesignated
Aircraft Category: Airplane
Year of Manufacture: 2015 
Amateur Built: Yes
Airworthiness Certificate: Experimental (Special) 
Serial Number: S12XXXC0HK0546
Landing Gear Type: Tricycle
Seats: 2
Date/Type of Last Inspection: April 26, 2020 100 hour 
Certified Max Gross Wt.: 1140 lbs
Time Since Last Inspection: 230 Hrs
Engines: 1 Reciprocating
Airframe Total Time:
Engine Manufacturer: Rotax
ELT: Installed, activated, did not aid in locating accident
Engine Model/Series: 912 ULS
Registered Owner:
Rated Power: 100 Horsepower
Operator: On file 
Operating Certificate(s) Held: None

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual (VMC)
Condition of Light: Dawn
Observation Facility, Elevation: KMKO,610 ft msl 
Distance from Accident Site: 19 Nautical Miles
Observation Time: 06:53 Local
Direction from Accident Site: 131°
Lowest Cloud Condition: Clear 
Visibility: 10 miles
Lowest Ceiling: None
Visibility (RVR):
Wind Speed/Gusts: / 
Turbulence Type Forecast/Actual:  /
Wind Direction: 
Turbulence Severity Forecast/Actual:  /
Altimeter Setting: 30.29 inches Hg
Temperature/Dew Point: 6°C / 4°C
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: Haskell, OK (2K9) 
Type of Flight Plan Filed: None
Destination: Haskell, OK (2K9) 
Type of Clearance: None
Departure Time: 06:30 Local
Type of Airspace: Class G

Airport Information

Airport: HASKELL 2K9
Runway Surface Type:
Airport Elevation: 588 ft msl
Runway Surface Condition: Unknown
Runway Used: 
IFR Approach: None
Runway Length/Width:
VFR Approach/Landing: Forced landing

Wreckage and Impact Information

Crew Injuries: 1 Serious
Aircraft Damage: Substantial
Passenger Injuries:
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 1 Serious
Latitude, Longitude: 35.864166,-95.655555(est)

Wagoner County Sheriff's Office
Deputies respond to plane crash South of Coweta, pilot flown to area hospital

On 05-09-2020 Wagoner County E-911 Dispatch received information of a plane crash South of Coweta in the area of East 205th and State Highway 72. Wagoner County Deputies Lt. E Crockett, E Patrick, B Sieg, D Clark, and Sgt. J Halfacre responded to investigate. Wagoner County Deputies were dispatched at 0825 hours and a deputy was on scene in minutes coordinating with Wagoner County Emergency Management and area first responders.

As additional first responders arrived, Deputy Sieg, Crockett, Patrick, and Clark all proceeded to the scene of the plane crash to assist the victim. Yocum Trucking allowed first responders to company golf carts and 4-wheelers to gain access to the crash site. Responders had to traverse muddy fields and heavy foliage to access the airplane crash site. Deputy Sieg relayed GPS coordinates continuously to Wagoner County E-911 Dispatch to direct first responders. Air Evac 83 responded to the scene to transport the victim due to his significant injuries. Wagoner County Emergency Management responded with ATV vehicles to allow access to the crash site.

The pilot sustained injuries in the crash and was transported by Air Evac 83 to a local area hospital for treatment. The Oklahoma Highway Patrol is investigating the crash in conjunction with the Federal Aviation Administration. The plane had taken off from the Haskell Airport before having unknown issues and crashing into a rural area of Wagoner County.

The Wagoner County Sheriff’s Office would like to thank Heath Underwood and his Wagoner County Emergency Management team, Stone Bluff Fire Department, Coweta Fire Department, Muskogee County EMS, Haskell Fire Department, Haskell Police Department, Air Evac 83 (Muskogee), Yocum Trucking, Muskogee County Sheriff's Office, and the Oklahoma Highway Patrol for their assistance.

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