• The continued reliance on ageing widebody aircraft is exposing structural weaknesses in out-of-production engine programmes, with the Pratt & Whitney PW4000 emerging as a major pressure point in 2025.
• While the engine family spans multiple variants and aircraft types, it is the 112-inch fan PW4000—used on early Boeing 777-200, -200ER and -300 aircraft—that is creating the most severe challenges for operators.

The narrowbody market is partially meeting the challenges of a constrained market with extended retirements. The
same is true of the widebody market, with even more pressures to extend retirement ages on the twin-aisle aircraft.
As a result, many of the older engines remain in demand beyond production cycles, resulting in aircraft being parked
for a lack of spare parts or limited MRO capacity. The most disruptive of the out-of-production engine challenges over
the past several months has been the PW4000.

The PW4000 is a flexible widebody engine, offering three major variants and take-off thrust ratings varying from
55,000 lbs. to 99,000 lbs. The engine is divided among the major variants by fan diameter size, with the original 94-
inch fan powering the A300, A310, 747-400, 767, and MD-11. The 100-inch fan was one of three engines selected to
power the A330-200 and A330-300. Pratt & Whitney followed with a 112-inch fan for the 777-200, -200ER, and -300
( Note the PW4000 was not an engine option for the 777-300ER or 777-200LR). It is this 112-inch fan that was
produced in the least quantities of the PW4000 family, and the variant that is creating deep challenges for operators
of the type today.

Since late summer of 2025, United Airlines has expressed challenges in finding available shop capacity and spare parts
for its fleet of PW4000-powered 777 aircraft. Many of these operated on the first 777s ever built, now exceeding 30
years in age. The challenges for United have been significant enough to reduce utilisation on PW4000-powered
aircraft, prioritising liftfrom other aircraft to backfill the expected capacity no longer available.

United controls the majority of 112-inch fan PW4000s, though other operators maintain sizeable fleets. Notably,
ANA, Korean Air, and Asiana operate 14, 8, and 8 aircraft, respectively, though United operates the majority of the
fleet. This is proving a unique challenge for United Airlines and Pratt & Whitney in that the fleet remains large enough
for United to rely on the aircraft for much-needed capacity, but too small for Pratt & Whitney or third-party suppliers
to invest in the future longevity ofthe program.

While the PW4000-powered 777s are expected to continue operating, the challenge of MRO capacity and spare parts
availability is expected to remain. This is likely to keep the values of engines and parts high, though extremely scarce.
Similarly, we expect utilisation on 777s with PW4000 engines to be reduced to account for the scarcity in parts and
shop capacity

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