FAA Adopts New AD for Diamond DA42

Order addresses uncommanded rudder deflection caused by a cracked nose landing gear hydraulic actuator rod end.

Meg Godlewski

Thursday, August 06, 2026 at 09:30 AM ET

Verified

Edited By:

Travis Tingle

Diamond DA42 [Credit: Robert Goyer]

Key Takeaways:

The FAA has issued an Airworthiness Directive (AD) for Diamond DA42 aircraft to address uncommanded rudder deflection caused by a cracked nose landing gear (NLG) hydraulic actuator rod end.
This critical issue can lead to NLG actuator failure, rudder control system interference, and reduced airplane control, prompting immediate action without prior public comment.
The AD mandates revisions to the airplane flight manual, repetitive inspections of NLG hydraulic actuator rod ends for defects, and replacement of any affected parts, with immediate flight restrictions and inspections as frequent as every 5 flight cycles for the 267 affected U.S. aircraft.

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The FAA is adopting a new airworthiness directive (AD) for the Diamond DA42 to address occurrences of uncommanded rudder deflection caused by a cracked nose landing gear (NLG) hydraulic actuator rod end.

According to the agency, this could lead to failure of the NLG actuator and interference with the rudder control system, forcing the rudder into left-hand deflection.

The FAA action follows an emergency AD issued in June by the European Union Aviation Safety Agency (EASA). EASA Emergency AD 2026-0125-E addresses occurrences of uncommanded rudder deflection that were reported due to a cracked NLG hydraulic actuator rod end.

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According to the FAA, this AD requires a revision of the existing airplane flight manual (AFM) for the aircraft to provide flight crews with “revised operating limitations, repetitively inspecting certain NLG hydraulic actuator rod ends for cracks, deformation, corrosion, damage, and free movement of the spherical bearing, and depending on the results of any inspection, replacing the affected NLG hydraulic actuator rod end with a serviceable part.”

The AD prohibits the installation of an affected NLG hydraulic actuator rod end unless certain conditions are met.

The FAA has determined that the risk to the flying public justifies forgoing notice and comment prior to adoption of this rule because the failure of the NLG actuator and interference with the rudder control system could result in reduced control of the airplane.

“Because this condition can occur without warning and vary from airplane to airplane, the FAA is requiring an immediate flight operating restriction for those airplanes that have 1,000 hours total time-in-service and a compliance time for inspections for some airplanes as low as 5 flight cycles (takeoffs and landings),” the AD states.

The FAA estimates the AD will affect 267 airplanes in the U.S. The cost of compliance with the AD is estimated to be $340 per airplane per cycle for inspection, which will take approximately four hours to complete, for a total of $90,780. Revising the AFM will cost approximately $22,695.