Cruise speed - TOO Early or TOO late

[shearder]

Hi All

I have been simming for years - BUT - I have never worried about arrival and departure time. I was busy with my first flight for the SAA virtual airline and I suddenly realized a problem.

I am either arriving too early or too late (after adjusting speed WAY down). What is the best way to calculate the speed i should be doing at X altitude to arrive on time and IF, for whatever reason, I see my time is out either late or early how do i calculate to adjust my speed to arrive on time?

Many thanks in advance.

Sean

[Carlo]

I suppose the best way to do that would be to fly using an FMC, if you're comfortable with that level of realism.
You can program the aircraft to fly each leg at specific speeds and altitudes, etc

[NWADC9]

Airlines add buffer times to accommodate traffic density and weather. Since FS isn't the real world, you'd be arriving early if you were to match the same flight in real life in terms of speed. Also, some airlines travel slower than the max cruising speed to safe fuel.

[Dennis]

A little answer to what might be the problem:

http://www.simairline.net/faq.html#4.11

Also, consider flight altitude and speed. If you're doing a short hop, why would you fly at normal cruising speed at 18,000 (or higher)?

[sanins192]

A lot of this comes with experience. You can use FMCs and the default FS GPS to work out your ETA, so you can adjust your cruise speed using that. Some aircraft (such as PMDG products) will arrive nearly on time every flight, since they use FMCs and calculate your cruise speed for you. Have a look on the Fleets page of each airline and it shows you the cruise speed for each aircraft. Some airlines, such as Virgin Blue, fly slower to conserve fuel, so this is reflected in the flight time.

[shearder]

Thanks to all who responded. I will try the flight I did again and see how i can get it to be better. Yes, i have PMDG's 737 800/900.

I was using a 3rd party FMC but cancelled it due to not sticking to the route as given by ATC in the IFR. However, i also read in here that some people cancel the IFR after takeoff and re-initiate before landing.