FAA Proposes AD for Diamond DA50 C Over Flap Actuator Failures

The Federal Aviation Administration (FAA) is proposing an airworthiness directive for Diamond Aircraft Industries GmbH DA 50 C aircraft after reports of flap actuator failures that, in at least one case, affected aileron control.

The proposed AD would apply to all DA 50 C aircraft, regardless of category, and address a condition that could prevent pilots from extending the flaps and potentially limit aileron travel.

According to the FAA, investigations found that a failed flap actuator could interfere with the aileron control system. One reported occurrence resulted in reduced aileron control. The agency said the condition, if left uncorrected, could reduce the pilot’s ability to control the airplane.

The proposal follows European Union Aviation Safety Agency (EASA) AD 2026-0140, issued July 15, 2026, which addressed the same issue.

Under the proposed directive, operators would need to inspect the flap actuator for displacement of the black slide grommet and check that the rod end bearing is properly secured. The actuator would also need to be modified, followed by recurring inspections of the torque seal on the jam nuts at the rod end bearing attachment.

The FAA proposal calls for an initial inspection within 50 hours time-in-service or 12 months after the AD’s effective date, whichever comes first. The actuator modification would be due within 100 hours or 12 months. After modification, repetitive inspections would be required at intervals of no more than 200 hours or 12 months, whichever comes first.

If an inspection reveals a discrepancy, corrective action would be required before the airplane’s next flight. The proposal would also prohibit installing unmodified flap actuators on affected aircraft.

The FAA estimates the directive would affect 30 airplanes on the U.S. registry. It projects an initial inspection cost of $85 per aircraft and modification costs of up to $2,675 per aircraft, including parts.

The agency is treating the proposal as an interim action while the manufacturer continues investigating the issue. Additional rulemaking could follow depending on the investigation’s findings.

The FAA is accepting public comments on the proposal through Dec. 28, 2026.