The European Union Aviation Safety Agency (EASA) has mandated a series of inspections and procedural updates for the Airbus A350 aircraft's auxiliary power units (APU) following recent failures attributed to corrosion. Airbus reported two incidents over the past two years where APU air intake flaps detached due to cracked hinges caused by corrosion pitting, as detailed in the new airworthiness directive (AD).
Investigations indicated that operating conditions, specifically flying under the permitted minimum equipment list (MMEL) with the APU flaps open and the unit inactive, increased stress and crack formation. To mitigate future risks, Honeywell has issued a service bulletin advising inspection protocols, while Airbus has recommended checks through its customer bulletin. The company also revised the aircraft's MMEL to reduce associated hazards.
The AD sets out that initial inspections should be conducted within four to twelve months, depending on specific operational circumstances, with subsequent checks every 24 months. It further mandates implementing the updated MMEL to enhance safety standards across the fleet.
Sean Broderick, Senior Air Transport & Safety Editor, noted that this directive aims to prevent recurrence of incidents linked to corrosion, emphasizing the importance of rigorous, routine maintenance. The measures reflect a proactive approach to ensure the continued safety and compliance of Airbus A350 operations, helping prevent potential in-service failures that could compromise safety and performance.
