The U.S. Federal Aviation Administration (FAA) has introduced a new Airworthiness Directive (AD 2025-25-12) aimed at enhancing the safety of Airbus A350-900 and A350-1000 aircraft. This directive mandates operators to upgrade their flight-control software to mitigate the risk of control-surface malfunctions due to hydraulic fluid contamination in critical electronic modules.
Hydraulic Fluid Contamination Risks
Investigations have revealed that contamination of Flight Control Remote Module (FCRM) electronic cards with hydraulic fluid can lead to uncommanded movements of control surfaces. This hazard is particularly concerning as both the elevator and rudder units share design characteristics, making them susceptible to similar risks. To address this, regulators have mandated a fleet-wide update to prevent potential incidents.
Transition from Interim to Permanent Solutions
This directive replaces a previous interim AD that required the removal and replacement of contaminated FCRMs. Such measures followed the discovery of several modules exposed to hydraulic fluid during the manufacturing process, which raised concerns about the safety of the aircraft. A notable incident highlighted the urgency for action, as it involved the loss of control of an outboard aileron surface.
Software Upgrades as a Permanent Fix
The FAA’s permanent solution involves an upgrade to the Flight Control and Guidance System (FCGS) software, specifically to the PRIM software standard P14.1.3 and SEC standard S14.1.2. This update is designed to eliminate the unsafe failure mode associated with hydraulic fluid contamination and effectively ends the need for earlier hardware replacements.
Impact on Airlines
Delta Air Lines, the largest U.S. operator of the Airbus A350 and the fifth-largest globally, is significantly affected by this new directive. Currently, Delta operates 38 A350-900s and has orders for six additional A350-900s and 20 A350-1000s. The FAA has indicated that this directive will apply to 39 U.S.-registered A350 aircraft.
Urgency of Implementation
The FAA has issued this directive without prior public comment, emphasizing the critical nature of mitigating risks associated with potential control failures. The threat of a runaway elevator or rudder surface could lead to severe consequences, making swift action essential for maintaining safety in the skies.
Compliance with European Regulations
The directive also aligns with the European Union Aviation Safety Agency (EASA) AD 2025-0197R1, and it prohibits the installation of earlier software versions once the mandated modification is completed. Operators are required to comply unless they have already implemented the necessary updates.
Takeaways
- The FAA’s new AD requires all Airbus A350-900 and A350-1000 operators to upgrade flight-control software by January 13, 2026.
- The directive addresses safety risks associated with hydraulic fluid contamination in electronic control modules.
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Delta Air Lines, as the largest U.S. operator of the A350, is significantly impacted by this directive.
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Compliance is mandatory, with a focus on preventing uncommanded control surface movements.
In conclusion, the FAA’s decisive action to implement this directive underscores its commitment to aviation safety. By focusing on software upgrades, the agency aims to create a more secure operational environment for A350 operators, significantly reducing the risks associated with hydraulic contamination. This proactive approach enhances the reliability of aircraft systems and reinforces the aviation industry’s dedication to safeguarding public safety.
Source: www.airwaysmag.com