Engine Problems Are Forcing United To Park Some Boeing 777s—And The Government Could Restrict Long Overwater Flights

United is storing Pratt & Whitney-powered Boeing 777s. A few engines could force a lot of schedule changes. And a few more incidents, there could be regulatory changes with United’s fleet that keep them from flying a number of important routes – the way they currently fly to Hawaii and Asia could be at risk.

So far United has been storing some Boeing 777s in the desert. They want the planes, but can’t consistently keep them flying. JonNYC points to one that was formally moved into storage at Victorville, California, last month – and more could follow – driven largely by engine parts availability.

trying to figure out a bit what's going on with UA's 777's. This one was not retired, it's officially being stored– and I expect more to follow.
Parts– certainly engines being part of that (maybe the biggest part)– are the issue and, depending on whom you listen too, a… https://t.co/fiGHv2ckAA

— JonNYC (@xJonNYC) December 18, 2025

There’s also a technical fear: that more engine events force United into tighter overwater operating limits on the planes, restricing how long the planes can fly overwater away from any diversion point.

someone explains:
"The engines have to meet a reliability standard. If there are enough failures at any airline, the standard isn’t met & the jets are no longer certified for ETOPS. They are maybe one or two incidents away from failing to meet the standard”

— JonNYC (@xJonNYC) January 13, 2026

someone adds:
"They(UA/FAA/PW) could reduce the ETOPS limit to either 180 minutes or 90 minutes. Worst case NON-ETOPS. Which would restrict them to a northern 9+ hour flight from JFK to LHR with flight scenario being you fly by JFK BOS YYR YFB NUK KEF SNN:GLA LHR .

At 120…

— JonNYC (@xJonNYC) January 13, 2026

Here’s what’s going on, why United is uniquely exposed, and what “losing overwater approval” would look like.

A Large Chunk Of United’s Widebody Fleet Is Affected

United has 96 Boeing 777s.

• 22 Boeing 777-300ERs
• 55 Boeing 777-200ERs
• 19 Boeing 777-200s

The Pratt-powered subfleet, legacy United planes from before the Continental merger, is 52 aircraft. United is the only U.S. airline operating 777s with these engines.

That means:

• ~ 54% of United’s 777 fleet (52 out of 96)
• ! 23% of United’s widebody fleet (52 out of 223, counting 777/787/767)

The average age of United’s 777-200 fleet is 27.5 years, and their 777-200ERs is 24.8 years. Older jets can be harder to support with spare parts, and that seems to be the case here.

The Pratt Engine Fan Blades Crack, And The Fix Is Slow

The engine here is the Pratt & Whitney PW4000-112, and it’s been at the center of several high-profile “fan blade out” events.

1. A large fan blade at the front of the engine can develop a fatigue crack over time.
2. If the crack grows undetected, the blade can break.
3. When a blade breaks at high speed, the engine experiences a violent event that can damage surrounding structures (and even start a fire).

The FAA’s 2021 emergency directive highlights the challenge of detecting cracks on the interior surfaces of hollow fan blades, requiring a specific imaging inspection method rather than a simple look-over.

Boeing and Pratt have been developing integrated engine/airframe design changes, with an FAA-set deadline requiring the fleet to incorporate changes by March 2028, while Boeing and United have pushed for more time. In the meantime that means repeated inspections, maintenance visits, amidst limited spare engines and shop time. So airframes sit around arond wait.

The Engines Have Been Involved In Major Incidents

In February 2018, United 1175 suffered a fan blade separation near Hawaii. The 777 on approach to Honolulu lost portions of the right engine inlet and fan cowl. Pilots shut the engine down and landed safely.

A blade with a crack was returned to service and eventually fractured, with training and feedback weaknesses playing a role according to the investigation that followed.

Meanwhile, United 328 suffered an engine fire and spread debris over a Denver neighborhood in February 2021. Shortly after takeoff, the 777 suffered a full-length fan blade separation on the right engine. That caused major nacelle damage.

A passenger on United 328 took this video of flames shooting out from the engine. Some people told me they said prayers and held their loved ones' hands as they looked out the window. Flight was on its way to Hawaii from Denver. Glad everyone onboard is safe #9News pic.twitter.com/c8TNYlugU2

— Marc Sallinger (@MarcSallinger) February 20, 2021

Within days of the 2021 Denver event, the FAA issued an emergency airworthiness directive requiring inspections of the Pratt engines before further flight. It became a multi-year program of repetitive inspections and tests, changes to engine inlets and related structures, and debris shields and other modifications. United had to keep more than 50 of these 777s out of service until repairs were made.

What Parked Pratt 777s Do To United’s Network

These Pratt 777s cover two very different kinds of flying in the United system:

1. High-density routes where United wants a lot of seats (leisure-heavy flying where the airline can fill a big aircraft).
2. Long-haul international routes where range and payload matter.

Take a handful of these jets out, and United has to do some combination of:

• Swap aircraft types (often to smaller widebodies like 787s or 767s)
• Reduce frequencies (same markets, fewer departures)
• Cut routes outright (especially thinner long-haul routes that don’t have easy substitutions)

Cranky Flier wrote about how these engine constraints forced United to adjust its routes, like not resuming service on Washington Dulles–Dakar and Newark–Stockholm.

Could United ‘Lose Overwater Approval’ For These Planes?

JonNYC relayed a claim that United could be “one or two incidents” away from failing the engine reliability standard that underpins permission for long overwater flying, with a possible outcome being reduced diversion-time limits (or, in the extreme, no long overwater authority).

There’s a reliability metric that matters, and a judgment call. The FAA tracks the rate of in-flight engine shutdowns as a key reliability measure. For two-engine aircraft:

• 0.05 per 1,000 engine-hours required for up to 120 minutes
• 0.03 per 1,000 engine-hours required for beyond 120 up to 180 minutes
• 0.02 per 1,000 engine-hours required for beyond 180 minutes

The FAA will not revoke an existing approval solely because of a high shutdown rate. They frame the response as:

• If the high shutdown rate is tied to a design issue, the operator shouldn’t automatically be punished for something not of their making.
• If the risk is attributed to systemic issues in the operator’s maintenance or operational practices, tailored action may be required, including reducing the airline’s permitted diversion limit.

A single shutdown can make the rate spike if the denominator (total engine-hours) isn’t large. So is it possible that diversion limits get reduced for this subfleet at United, as more issues occur. But it’s not automatic.

If it happened, United would lose the aircraft from long Hawaii routes, transpacific flights, and some long transatlantics. They’d have to reassign other aircraft types to those routes, and keep the affected airplanes on routes that stay close enough to diversion airports. And they’re not going to regularly fly awkward, fuel-heavy hug the coastline and Iceland routings to Europe.

It Would Be A Big Lift To Get Overwater Approval Back

Higher levels of long-overwater authority rests on sustained reliability results (including shutdown rates), an approved maintenance and operational program, and demonstrated performance over time.

A return to higher diversion-time authority would require a combination of corrective actions. Boeing and Pratt are still working through longer-term design improvements under FAA oversight. They’d have to demonstrate reliability on a rolling basis. And they’d have to satisfy the FAA that the risk has been brought back under control. But with spare engines and parts tight, they could get approval and still not have the planes available to fly.