EASA Orders Airbus A350 APU Flap Checks

The European Union Aviation Safety Agency (EASA) is mandating Airbus-recommended inspections of A350 auxiliary power units (APU) following two in-service incidents linked to a common problem.

Airbus reports two occurrences of APU air intake flap detachments in the last two years, the Dec. 2 EASA airworthiness directive (AD) explains. Probes of each found cracked hinges due to corrosion pitting.

Further investigation found the stress and cracking increased if the affected aircraft flew under permitted master minimum equipment list (MMEL) conditions with the APU air intake flap open and the unit off.

APU supplier Honeywell developed an inspection program and detailed the issue in an October service bulletin. Airbus, in its own customer bulletin, recommended operators the checks. The aircraft manufacturer also modified the A350 MMEL to mitigate the identified risk.

EASA’s AD, based on the Honeywell bulletin, orders initial APU air intake flap inspections within 4-12 months, depending on several factors. Follow-up checks are required every 24 months. The directive also mandates adopting the updated MMEL.