Delta ordered 25 A350-900 and 25 A330-900 four years ago (November 2014) to replace ageing Boeing 747 and 767 on Delta’s longer range routes. The shorter range A330-900 should be used for Americas and trans-Atlantic services, while the long-range A350-900 should fly the longer Asian trans-Pacific routes.
When Delta placed the order, the higher gross weight A330-900 was not fully defined. Airbus finally settled the growth version at 251t Maximum TakeOff Weight (MTOW) last year, by it extending the range with 700nm to 7,100nm using Airbus rules and a three-class 287 seat cabin. This compares with the standard range of the A350-900 of 8,100nm using a 325 seat three-class cabin.
With the 42 A330ceo (31 A330-300 and 11 A330-200) which Delta presently operate (Figure 1), the A330-900, which start arriving 2Q2019, will be extending a large fleet. The commonalities mean crewing will be easy and maintenance costs will be low, as Delta’s TechOps has achieved one of the lowest operating costs of any A330 fleet for its present A330s.
Delta does this change as the A330-900 with 251t MTOW is capable of replacing the A350-900 on many Asian routes, today flown by the A350.
To understand which we looked at present A350 routes, Figure 2.
The routes are focusing Tokyo, Seoul, Shanghai and Peking from Detroit and Atlanta. There is also an LAX to Shanghai and Detroit to Amsterdam route.
If we change the cabins to the Delta long haul configuration for both aircraft (293 seats three class for A330-900 and 306 seats three class for A350-900) and use a more airline oriented rule set (100kg passenger with bags, 5% en-route reserves, in-service deterioration and 80% load factors) we have an operational still air range for the A330-900 of 7,000nm and 8,000nm for the A350. The lower load factors for regular long-range flights for an airline like Delta compensate for in-service deterioration and higher reserves.
In Figure 3 we have mapped the Asian routes with Great Circle Mapper. The routes have still air great circle ranges of between 5,500nm and 6,200nm. Practical routes following airways and adapted to find best winds are up to 400nm longer.
As the routes from Detroit and Atlanta fly over Canada and close to the North Pole, the headwinds going westward are not as bad as if we flew straight west. Going straight west, as if we would fly LAX-Sydney, we would plan for 60kts headwinds or more during the winter. On the Delta routes, we shall plan with headwinds around 20kts or less than half the winds on western routes.
This means the still air routes are extended with 5% in range instead of 15%. So we shall add about 500 to 600nm to the above routes to reach practical planning conditions. It means the A330-900 in its 251t version, available by 2020, can fly all the routes flown by the A350-900 today.
We have also compared the seat-mile costs for the two aircraft types using our performance model. With the low Delta costs for maintenance for the A330 fleet, the operational seat mile costs are similar between the types.
This means Delta can use the slightly smaller and therefore cheaper A330neo on all routes to Europe and routes to Asia down to the Tokyo, Seoul, and Shanghai area where the capacity of the A350 is not needed. For any longer routes like re-opening the Hong Kong route, the A350 will be needed.
The shift from A350-900 to A330-900 for Delta is a rational move. The A330-900 is no longer a non-trans-Pacific aircraft from 2020. For operators with large A330 fleets, it will be attractive to first expand the A330 fleet while viewing the A350 for extra long routes (-900, -900 URL) and higher needed capacities (-1000).