Accident Brief: Two Died In Kolb TWINSTAR Accident

The NTSB report on a Kolb TWINSTAR accident in La Porte, Texas, that left two people dead.

Gemini Sparkle

Key Takeaways:

  • The accident was caused by the pilot's failure to maintain sufficient airspeed during a visual approach for landing, leading to an aerodynamic stall at an altitude too low for recovery.
  • The experimental amateur-built light-sport airplane, a low-inertia/high-drag type, was particularly susceptible to unintentional aerodynamic stalls due to its flight characteristics.
  • The pilot's experience level in experimental and light-sport airplanes, and whether transition training was received for the accident aircraft, could not be determined due to a missing logbook.
See a mistake? Contact us.

The private pilot, who had recently purchased the experimental amateur-built light-sport airplane, and a passenger were conducting a local flight in day visual meteorological conditions. Witnesses stated that the airplane departed and remained in the airport traffic pattern. While the airplane was on approach to the runway for landing, witnesses heard the engine power decrease then and immediately increase. The airplane appeared to enter an aerodynamic stall from a low altitude and impact terrain in a nose-low attitude. Postaccident examination of the airplane revealed no evidence of mechanical malfunctions or failures that would have precluded normal operations. Based on available information and examination of the wreckage, it is likely that the pilot did not maintain sufficient airspeed while maneuvering during the approach for landing. The airplane subsequently exceeded its critical angle of attack and entered an aerodynamic stall at an altitude too low for recovery.

The pilot’s logbook was not located during the investigation, and the pilot’s experience level in experimental and light-sport airplanes was not determined. Additionally, it could not be determined if the pilot had obtained transition training in the accident airplane, which was classified as a low-inertia/high-drag airplane. Low-inertia/high drag airplanes are particularly susceptible to unintentional aerodynamic stalls due to their margin between low cruise speed and stall speed and their tendency to experience significant airspeed decay with increased load factor (such as during a turn).

Toxicology revealed that the pilot was using pain and allergy medications at the time of the accident; however, whether the pilot had impairing levels of either of the medications around the time of the accident or whether the potentially-impairing medications degraded his ability to safely operate the airplane could not be determined.

Probable cause(s): The pilot’s failure to maintain airspeed during a visual approach for landing, which resulted in an exceedance of the airplane’s critical angle of attack and a subsequent aerodynamic stall at an altitude too low for recovery.

NOTE: The report republished here is from the NTSB and is printed verbatim and in their complete form. 

Are you an aviation enthusiast or pilot? Sign up for our newsletter, full of tips, reviews and more!

Isabel Goyer

A commercial pilot, Isabel Goyer has been flying for more than 40 years, with hundreds of different aircraft in her logbook and thousands of hours. An award-winning aviation writer, photographer and editor, Ms. Goyer led teams at Sport Pilot, Air Progress and Flying before coming to Plane & Pilot in 2015.
Subscribe to Our Newsletter

Get the latest Plane & Pilot Magazine stories delivered directly to your inbox

SUBSCRIBE