Noncompliance With Proper Construction Techniques Led To Stabilizer Failure

The Transportation Safety Board of Canada has issued a Safety Advisory to inspect Zenith CH series stabilizer attachment assemblies. While this safety advisory is not mandatory for aircraft certificated in the United States as experimental amateur built (E-AB), owners of all (high-wing and a low-wing) Zenith kit-built aircraft designated under the CH series are encouraged to review the safety advisory.

This advisory bulletin has been issued as a result of an accident that occurred in September 2016 to a Canadian registered Zenair Zodiac CH-601A that was built in 1994. The accident aircraft suffered a failure of the horizontal stabilizer attachment at an altitude of approximately 500 feet above the ground which resulted in the fatal injury to its only occupant.

According to the report, a structural inspection of the aircraft’s tail section revealed inconsistencies between the actual assembly and the applicable drawing set. Inconsistency with acceptable methods, techniques, and practices for inspection, repair or alteration, as outlined in FAA Advisory Circulars 43.13 1B and 2B were also identified.

Information contained in this safety advisory can be of particular interest to owners of these aircraft who are not the original builders. A review of the advisory will make it obvious to an original builder as to whether or not any of the specified inappropriate conditions could exist on the aircraft. However, a downline owner may want to involve a certified mechanic in the process of examining the Safety Advisory and determining its applicability to a specific aircraft.

Drawings for the stabilizer attach assembly are available from the Zenith Aircraft Company located in Mexico, MO.

(Image from TSB Safety Advisory)

FMI: Safety Advisory