777-9 vs A350-1000 Competitive Position

Background

The Airbus A350-1000 and Boeing 777-9 represent the top end, i.e. highest capacity, of their manufacturers’ commercial product lines. The following discussion compares the relative merits of the two aircraft and is the starting point for a future post on potential derivatives.

The following table outlines some key programme attributes

	1st Flight	Entry Into Service	Orders (end Feb 2026)	In-Service (end Feb 2026)
A350-1000	06/2013	2015	367	110
777-9	01/2020	2027 (Planned)	521 Firm	0
777-8	Not Flown, yet	2029-2030 (Est.)	35 Firm	0

The two aircraft are at very different stages of their product life cycle. The A350-1000 has been in service for over a decade, while the 777-9 continues through its protracted certification process due to typical programme delays, the fallout from MCAS accidents (specifically the role of the certification process) and the COVID-19-related disruption. Note the smaller A350-900 variant has acculated over 1,000 sales.

However, the 777-9’s headline sales figures substantially exceed the A350-1000’s, despite its considerable Entry-Into-Service (EIS) delays. This apparent advantage is primarily due to the huge 235 airframe order by Emirates, with a further 90 ordered by Qatar.

These sales reflect the region’s continued demand for high-capacity aircraft, as the 777-9 will be the largest capacity in-production aircraft once certified.

Boeing have also sized the 777’s wing and engines for operation in that region where the engines are routinely exposed to abrasive sand during ground operations, which accelerates engine wear.  

Conversely, the lack of any A350-1000 orders by Emirates is sometimes noted and discussed in the trade media. Emirates have cited the aircraft’s Trent XWB-97 engine’s less-than-expected durability, i.e. the length of time it operates safely between routine maintenance.

This primarily results from the A350-1000 and its Trent XWB-97 engines approaching their full growth potential. Note: the engine has not received the typical subsequent thrust increases after entering service.

However proximity to these limits usually delivers the most efficient fuel economy as both airframe and engine include no additional weight and drag needed for further subsequent growth.

Rolls-Royce describe the Trent XBW-97 as their ‘fastest and hottest engine to date’ – note that ‘fastest’ refers to the turbomachinery’s rotational speeds (not cruise speed). Consequently, Rolls-Royce’s continual development programme currently prioritises improved durability rather than improving fuel-efficiency.

By contrast, the 777-9 airframe and engine almost certainly include growth potential or higher design weights and engine thrust. The addition of an 800,000lb MTOW at Entry-Into-Service (EIS), compared to the pre-EIS 775,000lb value, will not surprise the author. The same applies to an engine take-off thrust rating increasing beyond the current 105,000lb.

Such contingencies are a standard process and widely observed on previous programmes, whose primary task is derisking the programme commercially and technically. They immediately counter any payload/range shortfalls relative to the guranteed values at EIS. Any additional contingency enables payload/range extensions beyond the pre-EIS vales.

PAYLOAD/RANGE COMPARISON

The following image compares the payload/range characteristics of the two 777 variants with the latest A350-1000 ‘New Product Standard’ variant. The analysis uses the author’s RAWAvCon models and Operating Empty Weights selected to deliver design ranges relatively close to the values marketed by Airbus and Boeing.

Note: RAW Aviation Consulting’s RAWAvCon performance models should deliver fuel burn and range capability results within +/-1% of Airbus or Boeing data, provided identical mission assumptions, and aircraft definition are used. Discussions with various organisations suggest that it generally meets this intent, but a lack of access to OEM data makes it impossible to guarantee.

WARNING: OEWs are not certified values and can vary significantly between aircraft of the same type for many reasons. They ALSO vary between flights of the same airframe due to differences in crew weight (number) and catering provisions.

Primary Conclusion:

A350-1000 payload range broadly matches the larger 777-9’s marketing maximum payload capability and the 777-8’s range capability at a constant payload  

The 777-9 payload/range capability will almost certainly improve with time. Firstly, the previously discussed design contingency will ensure the EIS aircraft meets or, ideally, exceeds the payload/range shown.

Subsequent upgrade programmes will almost certainly further improve the payload/ range characteristic in the coming decade.

While the A350-1000 NPS airframe and aircraft are already close to their growth limits, the NPS offered a wider cabin, intended to add an extra 20-30 economy sets beyond the 366 shown. The NPS cabin was widened by thinning the fuselage sidewall frame depth, much like the 777-9 relative to the earlier 777 variants.

This change will primarily move the A350 seating number up towards the 777s', although the market will decide whether a 10-seat abreast economy cabin becomes standard. Any effect on the OEW will be small, possibly a minor increase that pulls the entire payload/range characteristic downwards.

The 777-9 range map illustrates the reasoning behind the selected design range using RAW Aviation Consulting’s RAWAvCon WindsAloft capability. This capability closely matches Boeing WindTemp results.

The 777-9 can just reach New York (JFK), Melbourne (MEL), with the nominal 426-seat payload and the various mission assumptions used. GIG (Rio de Janeiro), Sydney (SYD) lie just outside the range circle when considering the ‘worst direction’ range circle.

However, it’s highly probable that GIG and SYD routes are economically feasible under airline assumptions and with operational variability, i.e. airline seat counts, load factors, more favourable winds (85% winds are pessimistic), modern wind-optimised routings (less wind with a smaller ground track penalty), less pessimistic deterioration levels (at times), decreased fuel reserves (more fuel for the main mission).

Los Angeles (LAX) and other parts of the southern US are a greater challenge, but might be possible with more targeted analysis. Likely post-EIS performance and design weight upgrades should help further.

The A350-1000’s longer range should bring LAX and New Zealand into range from Dubai with its nominal seating, under the same assumed conditions.

FUEL EFFICIENCY

I have used RAWAvCon aircraft performance models to assess the relative fuel burn per seat or passenger for the A350-1000, 777-8 and 777-9.

Given the considerable variation in seat counts fitted into a constant cabin geometry in airline service, the analysis considers multiple seat counts for each type. Note: the calculation assumes that each aircraft’s OEW do not vary with seat count. The analysis uses the same values as the Payload/Range image.

For clarity, the OEW remains independent of seat count. In reality, the OEW should slowly increase with reducing seat count (more premium seats are heavier than the economy seats they replace).

The nominal seat counts are the airframe company values for a 2-class cabin.  

Primary Conclusion:

The most striking conclusion is that the 777-8 and -9 fuel efficiencies for nominal seat counts broadly match the A350-1000’s.

Presumably, 777’s newer GE9X engines provide a minor competitive advantage over the A350-1000’s Trent XWB-97. The GE9X’s much larger fan diameter offers a 5% lower Specific Fuel Consumption (SFC) ‘versus any twin-aisle engine’ (from GE website). However, the GE9X’s substantially heavier propulsion weight and installation wetted area, i.e. drag, work against the SFC advantage to define the net effect on fuel burn.

Note: RAWAvCon modelling suggests the propulsion system, including nacelle and pylon, adds about 6-6.5t/ship set, an approximate 30% increase for a 7% thrust increase (although the GE9X thrust almost certainly includes substantial growth capability beyond 105,000lb.

However, the A350-1000’s OEW is considerably lighter than the 777 (about 30t). This is partly due to the 777’s ~3m longer fuselage and greater growth potential. However, the A350’s likely gains from its greater use of composite airframe structure and possibly more modern system architecture (Boeing’s 777X website makes no mention of a significant systems upgrade), and its lower mass propulsion system.  

The 777’s position will worsen slightly if it follows the same path to all other recent large aircraft programmes, i.e. post-EIS fuel efficiency rises a percent or two due to modest weight and fuel efficiency misses relative to the target values.

However, the 777’s protracted certification programme may have provided Boeing and GE with an opportunity for a further design cycle, addressing any underperforming or heavy airframe and engine components.

Subsequent aerodynamic and performance improvement activities will probably recover any shortfall in the following years.

One final comment, concerning seat count.

Interestingly, Boeing raised the 777-9’s nominal seat count from 414 to 426 (+2.9%) in the same cabin in 2022. The following year, 2023, the 777-8 fuselage was lengthened to match the 777-8F’s and the nominal seat count increased to 395 – a 8% increment from the previous value of 366 seats (I think).

The motivation for these changes is not reported, but achieving fuel burn per seat parity with the A350-1000 is a possibility – adding seats is the easiest way to improve fuel burn per seat. Time will tell how the customers configure the 777-9 and 777-8 cabins.

Seat counts are a complicated subject on wide-body aircraft, making it almost impossible to define equivalent comfort standards between competing aircraft. Airframe companies use this ambiguity to generally push up their own aircraft’s seat counts while lowering their competitors’ – this generally improves their aircraft’s competitive position in terms of fuel burn and operating costs per seat.  

For reference, in-service A350-1000 2-class cabins typically fall into two groups, with either 320-335 or 370-390 seats. The difference is mainly due to the length of their business class cabins, with lower seat counts due to longer business class cabins.  

SUMMARY

The 777-9 should enter service in 2027 and provide Boeing with a aircraft capable of competing with the A350-1000 in terms of fuel efficiency.

The 777-9 larger cabin will offer some differentiation for those customers looking to use it to compliment their even larger A380-800's before replacing them when the A380's eventually retire.

How the the A350-1000 NPS additional cabin width is used by operators remains to be seen. The additional tenth seat in the economy cabin cross-section should improve the fuel burn per seat, at the expense of seat width. At 9-abreast, the A350's cabin offers a wider seat (more comfort) than the 777-9 with a 10-abreast economy cabin, but a slightly narrower seat (less comfort) with the additional seat.

The market will decide.

Various press reports have mentioned stretch variants for both, i.e. a 777-10 and A350-2000. A future blog post will look at these in more detail, as well as the A350-1000ULR's project sunrise. At this point, it feels an easier option for the 777-9.

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