Boeing's 787-10 is at least four years away from making its debut with launch customer Singapore Airlines in 2018, but the super-stretched Dreamliner is already undergoing flight tests – well, of a sort.
The 787-9 test plane which spent last week undergoing heat tests in the centre of Australia also managed to perform a series of evaluations germane to its big brother, even though the -10 is still on the drawing board.
Photo gallery: Inside the Boeing 787-9 test aircraft
We're actually picking up some -10 testing on this configuration" explains Dominic Thacker, the 787-9’s Lead Flight Test Engineer.
"Some of the systems will be similar, this being a type derivative" Thacker tells Australian Business Traveller. "It's scaled up so we're looking at a couple of things like environmental-specific testing.
"If we can do some of those tests in advance on a similar airplane it helps us downstream and will save us time later."
Variations of an airplane's base model are faster to be declared airworthy because they represent only a relatively small number of changes to the original design.
“Being a derivative of the -8 there are standard tests that we need to do, but because a lot of the testing we actually did previously on the -8, this is just a subset of what a major model needs to go through” explains Ryan Smith, Boeing's Test Operations Manager for the 787-9 program.
"We've flown the -9 into testing very very quickly" Smith says, noting the 787-9's maiden flight took place on September 17 2013, just 10 months before the first commercial model is due to be handed over to Air New Zealand.
At 68 metres (224 feet) from tip to tail, the Boeing 787-10 will be just five metres longer than the 787-9 and 11 metres more than the original 787-8 Dreamliner.
And while it won't be able to fly as far as the 787-9 or even the 787-8, Boeing sees the 787-10 as being all about maximising bums on seats.
The 787-10 is expected to seat 330 passengers in a standard three-class configuration, although that count could nudge 350 – after all, Boeing describes the 787-9 as accommodating "250–290 passengers in three classes" yet Air New Zealand has 302 seats in its own three-class configuration.
Singapore Airlines and Etihad Airways have inked orders for 30 Boeing 787-10s each, at a list price of US$289 million, with United Airlines putting up its hand for 20 more and BA a further 12.
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