Is there a speed limit at or above 40,000ft

[Captain_JR]

It can fly faster and if you look at the chart Deer posted, the economical cruise speed for both the 747-400 and -8i is: Mach 0.86

Infinite Flight Fuel Burns (Estimates): XCub & TBM Added!

I have spent some time going through each of the aircraft that we have available to us and brought all of the fuel burns for all of the aircraft to one location. With these fuel burns is provided an Estimated Flying Time or EFT. This is the amount of time you could expect flying. The fuel burn and the EFT is provided in app under the weight and balance page. All I did was transfer what was given to an excel spreadsheet. As for the cruising speeds, I tested these speeds over a period of time to e…

---

I personally fly both of the 747 models (-400 & -8i) at Mach 0.86 for all my flights.