# Why is the A330neo more efficient than the A350 on shorter routes?

A330neo enables profitability on shorter ranges where the longer-range A350 and Boeing 787 aren't optimized.

For what reasons it is true?

A330 and A350 have almost the same size, weight and passenger capacity (the undeveloped A350-800 should be also more similar), and also engines are very similar, the same family Trent 7000 vs Trent XWB.

I thought that with almost similar planes, the bigger difference for calculating range could be only the fuel capacity (surely bigger for A350), but efficiency (in terms of lower weight due to advanced materials, lower fuel burnt due to new engines technologies) could be an "always true" concept.

So, why for shorter routes A330neo is more efficient than A350? Could not be enough to have an 350 with lower fuel capacity (in case shorter length) and maybe reduced engine power (the opposite of higher power in A350-1000) thanks to reduced weight?

I found this similar question, but I think that mine is more focused to general concepts because I'm asking also "what makes an aircraft more optimized for longer/shorter routes.

• I don't think fuel capacity is an issue in determining which one is more efficient for a very simple reason: airlines almost never fill tanks to full capacity unless there's a good reason to do so, e.g. regulation calls for it due to the distance to be flown, fuel is cheaper at the current station than at others, and the savings outweigh the cost of carrying the extra fuel to the next segment, etc. – Juan Jimenez Jan 30 '19 at 16:10
• @JuanJimenez Fuel capacity does have an impact on weight. For example, the standard A333 has no center tank, so they save weight on sealing, plumbing, pumps, and the interting system. Some other long range aircraft involve the installation of cargo bay tanks and activation of the trim tank. There's follow-on effects for designing for the mass of the extra fuel, in particular with landing gears (see A330 vs A340), bigger engines and a fuel dump system. – user71659 Feb 20 '19 at 0:38
• @user71659 Problem with that argument is that the A350 can carry more passengers, so in the end the additional hardware is a wash. – Juan Jimenez Feb 20 '19 at 9:36

              A330-900neo    A350-900
Seating       287–440        325 / 173 (ULR)
MTOW          251 t          280 t
OEW           137 t          137 t
Unit cost     US$$296.4 M US$$317.4 M
Thrust/eng    324 kN         375 kN


The A330 having fewer seats means a bigger chance of high utilization on any given flight (or having high-density small seats for shorter durations / dense routes). Shorter flights are typically more frequent on a weekly basis, so the flying customers get more spread out in a low-demand season.

With more frequent airport usage, the lighter MTOW means lower fees (typically it's a function of MTOW). Having the ability to carry some 30 tonnes more, pay for it, but not utilize it (carrying fuel), is not good.

They have similar Operating Empty Weights (OEW), which typically means a similar unit cost (~\\$2K/kg), but due to the generational gap of the airframe (development cost), getting a discount on the A330neo will be easier (9% bigger discount for the -900neo as of 2014).

Turbine engines give the best fuel economy when they are running near their design power. Having extra power that an airline won't use to carry lots of fuel for an ultra long-haul flight will mean not running at the best power setting. A smaller A350 could have a derated R-R XWB, but a tailored Trent 7000 (6 inches smaller fan diameter) will provide better economy outside the ultra long-haul segment.

The A330 maintenance is also mature, with enough supply, demand, and expertise, this translates to cheaper maintenance cost, especially if the customer already has A330ceo's – flying relatively short hops rackes up airframe/engine cycles more quickly.

In short, it does indeed depend on the route. Some carriers benefited from the full potential of the 787 performance, others didn't, but each carrier is sold the right projections. See: Did any Boeing 787 operator achieve the 20% fuel efficiency improvement over the 767?

Case in point, Emirates has recently (Feb 2019) decided to purchase 40 A330-900s and 30 A350-900s. (airbus.com)

• Very interesting answer. Just a note to A330-800... it seems lacks of orders compared to -900 version, so maybe to compare size, could be better to place side-by-side the two -900 versions of each model – Luca Detomi Jan 30 '19 at 15:42
• @LucaDetomi - I have missed that, thanks. See the updated post. – ymb1 Jan 30 '19 at 15:49