Airbus A220 Bleed Air Valve Swaps Mandated

Transport Canada (TC) has mandated an Airbus-recommended swap of A220 bleed-air valves to address high failure rates with the original parts that have led to multiple in-service incidents.

In an airworthiness directive issued April 15 and effective April 29, TC gives affected operators 9,390 hr. “total air time” to swap both engine bleed pressure regulating shutoff valves (PRSOVs). The time period translates to about five years of operation for the average A220, Aviation Week’s Tracked Aircraft Utilization (TAU) shows. The fleet averaged about 1,900 hr. per aircraft from 2022-2024, TAU shows.

TC’s directive says the issue affects the first 340 or so A220s produced—specifically, A220-100s up through manufacturer serial number (MSN) 50072 and A220-300s through MSN 55271. The permanent fix is to swap each Liebherr-supplied PRSOV with an updated part. Other regulators will likely adopt TC’s directive, turning it into a global mandate.

The directive also includes a new procedure to help mitigate risks of a faulty valve. The BLEED LEAK (Caution) procedure instructs pilots to reduce thrush or shut down an engine when the related message “is persistent,” the directive said. Adoption of the new steps applies to operators of a subset of the in-service fleet—A220-100 MSN 50001 through 50045 and A220-300 MSN 55001 through 55059, the directive said.

“There have been multiple in-service failures of PRSOV,” the AD said. “In case of failure, the inability to isolate a bleed air source combined with a bleed air leak on the same engine side could cause damage to surrounding structures and systems that can prevent continued safe flight and landing.” The directive does not elaborate on any in-service incidents.

Airbus issued a service bulletin in 2024 detailing the issue and its proposed fix for the affected fleet.

The A220 bleed air system has several functions, including cabin pressurization and feeding anti-ice systems. The AD’s actions include temporary operational restrictions to prevent a known PRSOV issue from triggering an incident. Within 60 days of its directive, affected operators must update master minimum equipment lists (MMELs) to prevent operation of an aircraft with an inoperative PRSOV in known icing conditions.

“Current [MMEL] items allow airplane dispatch with one inoperative PRSOV,” the AD explains. “In the event of dispatching the airplane with one or both engines bleed ON, the high failure rate of the PRSOV could lead to a total loss of bleed air systems, thus reducing safety margin and increasing pilots’ workload.”