AD 2021-14-12 Requires Inspecting The Horizontal Stabilizers, Including The Bondlines

The FAA is adopting a new airworthiness directive (AD) for all True Flight Holdings LLC Models AA-1, AA-1A, AA-1B, AA-1C, and AA-5 airplanes.

This AD was prompted by the report of an accident of an airplane exhibiting bondline corrosion and delamination of the horizontal stabilizers. This AD requires inspecting the horizontal stabilizers, including the bondlines, for cracks, buckles, corrosion, delamination, rust, and previous repair and repairing or replacing parts and applying corrosion inhibitor as necessary. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective July 27, 2021.

Supplementary Information: The FAA received a report of an accident involving a True Flight Holdings LLC Model AA-5 airplane that occurred on January 19, 2021. During flight, the outboard elevator attach bracket on the horizontal stabilizer detached causing loss of elevator control and significant damage to the airplane. An investigation identified corrosion and delamination of the airplane skin bondlines around the area of the horizontal stabilizer where the elevator attach bracket was attached. Multiple field reports have identified additional instances of corrosion and delamination of skin bondlines around the horizontal stabilizer and other primary structures.

All Models AA-1, AA-1A, AA-1B, AA-1C, and AA-5 Traveler airplanes have horizontal stabilizers that are similar in design and use the same attachment method for the elevators. The affected airplanes are constructed using a metal-to-metal bonding process. While the bond adhesive remains structurally sound throughout the aging process, factors such as corrosion and freezing moisture may compromise the structural integrity of some of the bond joints. This can lead to delamination of the skin from the primary structure.

Field reports indicate that bondline inspections are not being adequately performed during routine inspections. The FAA has determined that a more thorough inspection is necessary to reliably identify corrosion and delamination of bondlines in these critical areas, including the horizontal stabilizer.

This condition, if not addressed, could result in reduced structural integrity with consequent loss of control of the airplane. The FAA is issuing this AD to address the unsafe condition on these products.

FMI: www.regulations.gov