Originally Posted by John Farley
Personaly I see this as a six decade programme that started for real say in 2000.
The first decade [2000-2009] sees the start of flying.
The second decade [2010-2019]covers most of the original development and flying machine clearances.
The third decade [2020-2029]sees the military really getting to grips with what they can and cannot do with it. Plus the manufacturer is testing significant upgrades.
The forth decade [2030-2039]it is the aircraft/system to beat plus upgrades are starting to reach the fleet.
The fifth decade [2040-2059]ditto and all the fleet will have reached the final standard.
The sixth [2060-2069]is where serious plans for its replacement have started.
Given the time frames you describe (and I have no argument with them), surely replacement planning must start in at least decade 2 or 3. Otherwise, assuming similar development time, F-35 will have to remain operational to decade 9 or 10 before its replacement is fully capable!