NTSB Asks FAA to Prohibit Further Flight of Light Sport Airplane Tied to In-flight Breakups

Recommendations apply to the Zodiac CH-601XL, a low-wing, fixed-gear, single- engine, two-seat general aviation airplane designed by Zenair Inc.


In addition to the urgent recommendation to the FAA on prohibiting further flight of the Zodiac CH 601XL, the Safety Board issued the following seven additional recommendations to the FAA:

  • 1) make a comprehensive evaluation of the wing and aileron system on the Zodiac CH 601XL to identify design and/or operational changes that will reduce the potential for flutter;
  • 2) notify owners of Zodiac CH-601XLs of any design and/or operational changes to the CH 601XL and require them to implement the changes;
  • 3) work with ASTM International to incorporate standards for light sport airplanes that would reduce the likelihood of encountering in-flight flutter;
  • 4) evaluate the stick force gradient at the aft center of gravity and especially at the higher Gs, and notify pilots of such effects;
  • 5) develop standards on stick force characteristics for light sport airplanes that minimize the possibility of pilot’s inadvertently over-controlling the airplane;
  • 6) ensure that the pilot’s airspeed indicator accurately reflects the Plane’s velocity and update pilot operating handbooks (POHs) accordingly; and
  • 7) work with ASTM International to ensure standards for light sport airplanes result in accurate airspeed indications and appropriate documentation in new airplane pilot operating handbooks.

The Board's investigations have identified several areas in which the design standards for light sport airplanes were deficient. ASTM International provides the standards that are developed by industry working groups. The NTSB has asked the ATSM to take the following actions:

  • 1) Add requirements to ensure the standards for light sport airplanes reduce the potential for aerodynamic flutter to develop;
  • 2) develop standards on stick force characteristics for light sport airplanes that minimize the possibility of pilot’s inadvertently over-controlling the airplane; and
  • 3) ensure standards for light sport airplanes result in accurate airspeed indications and appropriate documentation in new airplane pilot operating handbooks.

To view the safety recommendation letter to the FAA click here. To view the safety recommendation letter to ATSM International click here.

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