Spirit Airlines Inc. has grounded seven planes due to problems with its Pratt & Whitney engines and the carrier expects to take more aircraft out of service in the coming weeks.

The budget carrier said Thursday that another seven jets will be removed after Labor Day through the end of the year and potentially more after that as the engine-maker assesses the full scope of a recently identified issue. Pratt parent RTX Corp. last week disclosed a manufacturing flaw in the geared turbofan that will require removal and inspection of more than 1,000 engines worldwide.

Read More: RTX Slumps as Engines on Top-Selling Jet Show New Flaws

“This new issue is yet another frustrating and disappointing development,” Spirit Chief Executive Officer Ted Christie said on a conference call to discuss quarterly results. The carrier expects to learn later in September how many more of its engines might be affected.

The comments underscore the growing dissatisfaction by airline customers as Pratt tries to get a handle on another glitch with the engine, which is one of two options to power the top-selling Airbus SE A320neo family of jets. Spirit said it’s the largest operator of GTFs in the US with the highest number of engines produced during the period involved in the latest issue.

Carriers including JetBlue Airways Corp. have recently cited Pratt-related issues weighing on their operations. Deutsche Lufthansa AG, Europe’s biggest airline group, said that 13 of its planes will be idled in coming months due to the GTF problem, while Hungary’s Wizz Air Holdings Plc said it’s cutting into capacity growth.

RTX executives have apologized for the disruption to customers’ flight plans, with CEO Greg Hayes saying last week that the company will “make the airlines whole.” RTX declined to comment further Thursday.

Details and timing for reimbursements haven’t been determined, Christie said.

The latest groundings will reduce Spirit’s third-quarter revenue by 1.5%, on top of a nearly 6% cut from earlier engine-related problems, Chief Commercial Officer Matt Klein said.

The carrier expects to have at least 10 aircraft out of service for most of 2024 because of previously identified engine issues and a spike in scheduled engine checks caused by a shorter-than-expected life of some parts. The number excludes those that might be parked due to the latest manufacturing problem. Spirit recently reversed pilot attrition, meaning that the additional groundings will force it to carry more aviators than needed in the fourth quarter and into early 2024.

(Updates with company comment on revenue effect in sixth paragraph)