Relief is in sight for airlines grappling with current-generation engine reliability issues, but some carriers may have to put up with delays getting parts or airworthy engines for several more years.

“We are not yet at the level we and our customers expect,” said Chris Calio, President and COO of Pratt & Whitney parent Raytheon Technologies, on a recent earnings call. “This has put stress on the operations of the fleet. We continue to develop upgrades from the current [PW1000G] configuration to improve durability. We are also expanding our [overhaul] capacity and working to reduce shop visit turnaround times to improve service availability.”

Aviation Week Network’s Fleet Discovery showed a global fleet of 2,976 Airbus A220- and A320neo-family aircraft in service as of April 25. Of these, 11% were listed as either stored or being flown infrequently—once per week or less. While engine-reliability issues are not to blame for all of the inactivity, it is playing a large role, particularly in the harsh-environment regions.

While both PW1000G and CFM Leap customers are seeing issues, the problems are far more widespread in the Pratt fleet. Most of CFM’s logjams are stemming from removals at carriers operating in harsh environments, such as the Middle East, and most affect Leap-1As in the A320neo family fleet, not the 737 MAX’s Leap-1Bs. The Pratt problems are more numerous and widespread.

Pratt has a 43% share of the A320neo-family fleet, with CFM Leap holding the balance. But 70% of the low-activity aircraft are powered by PW1000s, Fleet Discovery shows.

Among the hard-hit carriers are India’s largest airline IndiGo, with 40 of its 165 A320neos and 10 of its 79 A321neos not in regular service. The fleets are a mix of CFM and Pratt-powered aircraft, but Fleet Discovery shows only Pratt-powered aircraft out of service. Indian ULCC Go First Airlines has 29 of its 50 Pratt-powered A320neos on the ground.

Florida-based ULCC Spirit Airlines has been dealing with a moving target of unavailable Pratt-powered A320neos. Executives said recently that they are planning for disruptions for the next 7-10 months.

Among the exclusively Pratt-powered A220 fleet, nearly 20% of the 262 in-service aircraft were listed as not flying regularly, including 26 in storage.

“[We] are running as fast as we can to continue to insert upgrades into the fleet during shop visits,” Calio said, adding that Pratt is “only about 50% of the way through the fleet” with the latest so-called “block D” improvements that target combustors. 

Pratt is also phasing the next-generation PW1000G, the Advantage, into production, integrating lessons learned from the current PW1000G fleet.

“We’re operating in some very harsh environments,” said Raytheon Chairman and CEO Greg Hayes. “We probably didn’t spend enough time testing for those harsh environments, specifically places like India. And that’s where we’ve seen the lower life on the combustor [and] turbine blades, just because of the harsh conditions there.”

“We have the Advantage coming online,” Hayes continued. “It’s got a lot more testing. It’s got all the learnings from the existing fleet. This should be significantly more durable out there in terms of time on wing. It’s going to take us a couple of years before we can get all of those upgrades introduced.”

Pratt hopes to have its new production fully transitioned to the Advantage variant by 2026 at the latest. In the meantime, it will continue to add maintenance, repair, and overhaul (MRO) capacity and develop repairs to help keep the current fleet operating.

“We’ve had some part constraints and shortages and labor in our MRO network, which has which has impacted our ability to output MRO to the levels that we and our customers want, which is why we’re adding more capacity to that MRO network,” Calio said.

Both Pratt and CFM have been expanding engine repair networks in anticipation of a rise in shop visits as the PW1000G and Leap fleets mature. Delta Tech Ops has recently added capabilities to service certain variants from both families, while Pratt added Asia-Pacific capacity for PW1000G work via a tie-up with Mitsubishi Heavy Industries Aero Engines.