EASA AD 26-097 — Flight Controls – Angle of Attack Probes – Functional Checks

Summary

EASA Airworthiness Directive Proposal PAD No. 26-097 addresses functional checks of the angle of attack (AoA) probes heating elements on ATR 42 and ATR 72 aeroplanes. It applies specifically to Thales AoA probes with Part Number C16363AA installed on various ATR 42 and ATR 72 models. The directive aims to ensure continued airworthiness by requiring repetitive functional checks to detect degradation of the heating element that could lead to ice accumulation and loss of stall protection.

What Changed

This new proposed Airworthiness Directive introduces mandatory repetitive functional checks of the AoA probe heating in-rush current on affected ATR 42 and ATR 72 aircraft. It establishes inspection intervals based on measured current values and requires replacement of probes if heating performance falls below a critical threshold. The directive also mandates reporting of inspection results to ATR and sets conditions for installation of affected parts.

Why It Matters

This proposal is critical for operators and maintenance organizations as it addresses a potential safety risk from degraded AoA probe heating that could cause ice buildup and stall protection failure. Compliance ensures early detection and correction of probe heating issues, maintaining flight safety and regulatory compliance. It also provides clear instructions and intervals for inspections, helping maintenance teams plan and execute required tasks effectively.

What To Do

Operators of ATR 42 and ATR 72 aircraft with affected Thales AoA probes must perform initial functional checks within 18 months of the AD effective date or aircraft reference date, depending on the group classification. Subsequent checks must be repeated at intervals defined by measured heating current values. If heating current is below 0.93 A, the probe must be replaced before next flight. Inspection results must be reported to ATR within 30 days of each check.