EASA AD BR-2025-04-01
Stabilizers - Horizontal Stabilizer Backlash - Inspection / Replacement
Summary
Brazilian Airworthiness Directive AD No. 2025-04-01 issued by the Agência Nacional de Aviação Civil (ANAC) mandates inspection and possible replacement of horizontal stabilizer components on Embraer EMB-505 aircraft. The directive addresses potential invalid horizontal stabilizer backlash test results that could compromise flight safety. It requires compliance with Embraer Service Bulletin 505-27-0034, revision 02, dated December 6, 2024.
What Changed
This new airworthiness directive introduces mandatory inspections of the horizontal stabilizer backlash and specifies replacement procedures for attachment parts and pitch trim actuators if backlash exceeds allowable limits. It establishes compliance intervals based on aircraft grouping and flight hours and provides detailed part numbers for replacements. The directive also grants credit for previous compliant actions performed under earlier service bulletin revisions.
Why It Matters
This directive is critical for maintaining flight safety by preventing excessive horizontal stabilizer backlash, which can cause aeroelastic vibrations and reduce aircraft controllability. Operators and maintenance organizations must ensure timely inspections and corrective actions to avoid unsafe conditions. Compliance ensures continued airworthiness and regulatory adherence for Embraer EMB-505 operators in Brazil.
What To Do
Operators of Embraer EMB-505 aircraft must perform a functional check of the horizontal stabilizer backlash within 12 months or 750 flight hours for Group 1 aircraft, and within 24 months or 1000 flight hours for Group 2 aircraft, whichever occurs first. If backlash exceeds 0.034 degrees, specific replacement actions for hinge points and pitch trim actuators must be carried out following the procedures in Embraer Service Bulletin 505-27-0034 revision 02. All compliance must be recorded in maintenance logs, and alternative methods of compliance require ANAC approval.