EASA AD 2026-0170: Engine – Propeller Gearbox – Inspection

What to do

Operators must inspect the propeller gearbox for missing oil spray nozzles and M7 x 16 hexagon screws within specified compliance times: before next flight for gearboxes with less than 25 hours operation, or within 5 flight hours but no later than 12 months for those with 25 or more hours. If missing parts are found, the gearbox must be replaced with a serviceable unit before further flight. Installation of only serviceable gearboxes or engines equipped with serviceable gearboxes is permitted from the effective date.

Summary

EASA Airworthiness Directive 2026-0170 is an airworthiness directive addressing the inspection of propeller gearboxes installed on certain light sport and general aviation aeroplanes equipped with BRP-Rotax 912 ULS2 engines. The affected aircraft include Evektor SportStar RTC, Tomark Viper SD-4 RTC, Breezer B600, and Czech Aircraft Group PS-28 Cruiser models. The directive mandates inspection for missing oil spray nozzles and securing screws in the propeller gearbox to prevent potential engine oil loss or uncommanded engine shutdown.

What changed

This new airworthiness directive introduces a one-time inspection requirement for the propeller gearbox on the specified aircraft and engines to detect missing components that could compromise engine operation. It also establishes compliance groups based on gearbox operating hours and allows replacement with serviceable gearboxes as a corrective action. The directive extends previous emergency AD requirements to additional engines without EASA type certificates but certified as part of the aeroplane.

Why it matters

This directive is critical for aviation professionals to ensure continued airworthiness and safe operation of affected aircraft by preventing potential in-flight engine failures caused by missing gearbox components. Operators and maintenance organizations must comply to avoid uncommanded engine shutdowns and possible loss of control. Compliance teams need to track affected serial numbers and ensure timely inspections and corrective actions to meet regulatory requirements.