en.Wedoany.com Reported - The U.S. Federal Aviation Administration (FAA) has set the compliance deadline for nacelle upgrades on Pratt & Whitney-powered Boeing 777 operators to March 2033, extending the original deadline by five years.

In a decision issued on June 16, the FAA rejected Boeing's request to postpone airworthiness limitation compliance (or maintenance instruction updates) to March 2038. At the same time, the FAA proactively granted Boeing an additional two years, until March 4, 2029, to submit all design changes.

A 2022 exemption had given Boeing until March 2027 to complete proposed changes, with operators having an additional year for integration. Pratt & Whitney developed modifications based on three in-service engine failures in 2018, 2020, and 2021. Due to the complexity of the work, Boeing petitioned the FAA in May 2025 for a longer timeline than stipulated in the 2022 exemption.

Boeing's recent petition included project progress updates, which the FAA treated as proprietary information. Citing the "complexity" of the project, the agency determined that Boeing needed more time to complete its share of the work.

In its June 16 decision, the FAA stated that after reviewing proprietary data and project schedules, it concluded that Boeing was unlikely to submit all design changes demonstrating full compliance for FAA approval by March 4, 2027. Therefore, extending the deadline by two years to March 4, 2029, is in the public interest.

The Pratt & Whitney-powered 777 fleet was grounded in February 2021 after a third in-service incident. Pratt & Whitney, Boeing, and the FAA developed a return-to-service plan, including immediate modifications to the inlet and thrust reverser, along with an inspection program. Other changes, such as fan cowl and engine flange modifications, are subject to the 2033 deadline.

The new timeline compresses the window between Boeing's deadline to complete design changes and operators' deadline to implement them, but the practical impact may be minimal.

United Airlines operates the largest fleet of Pratt & Whitney-powered 777s, but the fleet is shrinking. According to Aviation Week Fleet Discovery data, there are currently 40 in service and 2 parked. At the time of the grounding in 2021, United had 52 PW4000-powered 777-200s.

The global fleet size (approximately 120 five years ago) is also decreasing. Fleet Discovery data shows 71 in service, 6 parked, and another 25 in storage but not officially retired.

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