Originally Posted by
FlightDetent
I am confused, t-bag. Addmitedly not knowing how 787 FMC speed schedule works, but at at the moment I am scratching my head around your description.
1) At FL370, a reasonable actual level for your scenario, M84 = 277 kt IAS.
2) ATC issued a speed reduction, and the FMS / crew (*) carried 0.84 in the descent, accelerating until reaching the crossover altitude.
3) At some point, your non-compliance become a concern and questions were raised as ATC can see the actual IAS. At that point, your IAS was probably being observed for quite some time already, before they spoke up.
...
See this is where I obviously have a different opinion - because I do not see this as non compliance. ATC did not issue a speed reduction, they issued a fixed speed to fly at whenever converting to IAS - which it sounds like t-bag did.
The problem here seems obvious in that with FMC derived speed scheduling, ATC doesn't know when "transition" is and flight crew (including myself and colleagues) do not see "250kts on conversion" as an immediate request to slow towards 250 when able, we understand that to me literally on conversion so will maintain a fixed mach and therefore potentially higher IAS until converting.
Having one party believe there is non compliance with an instruction and having the other believe they are complying perfectly is obviously not a good thing, and I can tell you that myself and my colleagues would act as t-bag did.
250 knots as soon as possible would make me reduce to 250 knots as soon as possible so that one works with me!
