How Flying Works
Why Is the Boeing 777X Still Not Flying Passengers?
Boeing’s 777X — the largest twin-engine jet ever built, and the intended replacement for the aging 777-300ER and, for several carriers, the Airbus A380 — was supposed to enter service in 2020. As of Boeing’s most recent update, the certification and first-delivery target now sits in 2027. That’s not a minor schedule slip; it’s roughly seven years, and it’s cost the program an estimated $15 billion in overruns. The reasons are real, specific, and mostly outside the airframe itself.
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The FAA queue, not just the aircraft
The single biggest factor isn’t a problem with the 777X design — it’s where the program sits in the FAA’s certification queue. The back-to-back 737 MAX accidents of 2018-19 permanently changed how closely the FAA scrutinizes Boeing’s certification work, and that heavier scrutiny has itself caused severe, ongoing delays to the MAX 7 and MAX 10 variants’ own certifications. FAA Administrator Bryan Bedford has stated that 777X certification work follows that MAX 7/MAX 10 work in sequence — meaning the 777X isn’t just waiting on its own process, it’s waiting behind someone else’s.
The engine problem that actually blocks the routes it’s built for
Separately, and specifically, the GE9X engine — the largest jet engine ever built, developed by GE Aerospace for the 777X — has had two real technical issues: first a thrust-link fatigue problem, and more recently a durability issue in the engine’s “mid-seal” component. That second issue matters more than its narrow technical description suggests, because it specifically affects ETOPS certification — the approval that lets a twin-engine aircraft fly extended routes far from a diversion airport. The 777X is a long-haul, twin-engine aircraft built explicitly for exactly those routes; without ETOPS approval, it can’t yet do the job it was designed for, regardless of how the rest of the airframe performs.
The real numbers
The 777X program, in real numbers
2020
Original service-entry target
First set before the program's first delay
2027
Current certification target
Per Boeing's October 2025 update
~$15B
Program overruns to date
Cost of delays and rework since program launch
6
Major airlines waiting
ANA, BA, Cathay Pacific, Lufthansa, Qatar, Singapore Airlines
What airlines are doing while they wait
Airlines that ordered the 777-9 as a long-haul flagship — All Nippon Airways, British Airways, Cathay Pacific, Lufthansa, Qatar Airways and Singapore Airlines among them — haven’t had the option to simply wait idly. Each has had to extend the operational life of older widebodies — 777-300ERs, Airbus A380s, Boeing 747-400s — well beyond their originally planned retirement, absorbing the maintenance and fuel-efficiency cost of flying older aircraft longer than intended. That knock-on cost, spread across every airline in the queue, is arguably the least visible part of the 777X story but one of its most expensive.
Sources & Further Reading
Common Questions
Frequently Asked Questions
When was the 777X originally supposed to enter service?
2020. As of Boeing's October 2025 update, certification and first delivery are now targeted for 2027 — making the program roughly seven years behind its original schedule.
Is the delay mainly about the aircraft itself, or something else?
Both, but the bigger single factor is regulatory sequencing. The FAA's own leadership has said 777X certification work follows the 737 MAX 7 and MAX 10 certifications in the queue — a direct, lasting consequence of the intensified scrutiny the agency applied to Boeing after the 2018-19 MAX accidents.
What specifically is wrong with the GE9X engine?
A durability issue with the engine's "mid-seal" component, following an earlier thrust-link fatigue problem. The mid-seal issue specifically affects the ETOPS approval the aircraft needs — the certification that allows a twin-engine jet to fly long routes far from a diversion airport, which is exactly the kind of route the 777X is built for.
Which airlines are most affected by the delay?
ANA, British Airways, Cathay Pacific, Lufthansa, Qatar Airways and Singapore Airlines all have the 777-9 slated as a long-haul fleet centerpiece, and have had to extend the service lives of older 777-300ERs, A380s and 747-400s to bridge the gap.