I’ve always had a keen interest in the aircraft development process.
I remember hearing that, in the past, new aircraft were often developed starting with the largest variant first - for example, the A350-1000 rather than the -900, or the 777-300ER rather than the -200.
My question is: how long does this kind of redesign development usually take? For instance, how long did it take to transition from the 787-10 to the 787-9? And which part of the process tends to take the longest, or be the most difficult?
