Originally Posted by
ced0802
Thanks a lot Paco.
Where I am missing something I guess is, as we go higher, our IAS decreases due to Density decreasing. TAS must increase to maintain our lift.
But how can we generate more TAS without adding power/thrust?
The aircraft doesn’t know or care what TAS you’re doing, hence the speedo doesn’t shot TAS. TAS is calculated and is then displayed, it can’t be measured directly. It’s your IAS that gives you your lift and what the wings think they’re doing. It reduces for a given TAS due to compressibility effects, more obvious at altitude.
That this relates to a certain TAS is only relevant for you really when it’s converted to your Mach number, which their will be a limit of. Have a look at the picture below. Quite happily at 260kts, TAS is about 455, which puts the Mach number at 0.79.
Don't get too hung up on it, there’s some lovely CDMVT charts that you’ll be fed to learn it all, and the question bank for when you actually take your exams. And when actually flying, just avoid the red bits 🤷♂️