The FAA issued a new airworthiness directive Tuesday requiring inspections of pitch trim systems on certain Fairchild/Swearingen SA226 Metroliner and SA227 Merlin aircraft following reports of failures during flight. The directive, which takes effect Dec. 1, addresses concerns that moisture entering the trim actuators could cause them to malfunction and affect aircraft control. The FAA estimates that 198 U.S.-registered airplanes are affected.
“The unsafe condition, if not addressed, could result in pitch trim actuator failure and reduced control of the airplane,” the FAA stated in the final rule.
In an earlier proposed rule, the FAA disclosed that it had received six reports of in-flight pitch trim actuator failures attributed to corrosion. The agency traced the problem to openings in certain Simmonds-Precision actuators that allow moisture to enter the internal mechanism. The FAA did not provide details about the individual flights or how crews responded to the failures.
The new directive requires certain Metroliner and Merlin operators to inspect the affected components for damaged or missing sealant and conduct recurring operational checks. Depending on the condition of the actuator, repairs or replacement may be required before further flight.
The AD also calls for recurring inspections every 1,000 flight hours or 12 months, alongside operational checks every 250 to 300 flight hours or six months, depending on the specific actuator installed.
