In an aircraft, even a minor change has to be fully tested. This testing requires time. Block 3 has had quite a few internal under the skin changes, which has required testing. After each test things are again tweeked to get the optimum output out of the plane. Sometimes things do not work and you have to go back to the design board. Sometimes multiple variations may have to be tried to see which suits the fighter the best.All of these things take time, money and effort.
The last time I checked PAC was not an institute called HAL and JFT was not a plane called Tejas. Haa haa.I hope this baby is ready to fly before it flies. Otherwise...
It's still a relatively big jump, e.g., three-axis fly-by-wire, AESA radar, increase payload, etc. So, even though there are limited structural changes, the few changes they made require a lot of testing. That said, besides its range and payload limits, the Block-3 is a soundly modern fighter, it has all of the contemporary technologies you need.
Any word FLIR?
radar cross section reducing 'pseudo-stealthy' airframe...doesn't that mean that their will be visible changes in the airframe?
