FPLTOIF for the first time

Hey there I’m using fpltoif for the first and I’m not a real pilot so can’t understand this. Can anyone please help. Thank’s.

3 Likes

That’ll be your speeds for different stages of flight. 250 kts under 10,000, 300 under FL280 and M0.78 above FL280.

9 Likes

OK Thank you.

Slight correction to @TaipeiGuru, it’s only for the climb and descent part, for cruise use the normal cruise speed of the aircraft.
You don’t have to follow the profile, especially descent cuz STAR often have a 280 limit.

1 Like

That’s literally what the last number represents. Your cruise. .78 is the cruising speed of the aircraft.

4 Likes

You seem to be using an A320

250kt to 10000’
300kt above 10000’
When 300kt=.78M (usually around 24000-26000)
Then you adjust your speed down to maintain .78M until reaching top of climb and then you’ll be cruising at either .78M or .80

If you’re using an A320-the fuel factor in simbrief is -15 that will give you close to perfect fuel burn on the SB flight plan!

As an aside- .78M at FL280 where the IF autopilot changes over from speed in Knots to speed in Mach is usually between 292-296kt depending on air density/temperature etc. So as you keep climbing from say FL265 up, you’ll need to keep dropping a knot or two off your speed to maintain .78M

Here is an example of cruise speed being different:
B757 climb profile is 250/290/78 but cruise is M.80

Yea i know. It makes a whole what? 5 minute difference if that. Now if it’s telling you to cruise at .78 in a A388 well then somethings is wrong. But the difference between.78-.80 is so marginal.

It can mean 30-50kt ground speed though which could potentially give you an arrival time of 30 min to almost an hour earlier than .78 🤷‍♂️

Guys, don’t forget this user is not an expert. I would’ve kept it simple and try not to confuse him.
Just my 0.02c

3 Likes

i think it’s worth mentioning since some aircraft have different climb and descent mach speeds
eg. CRJ9 has .77 for climb and .74 for descent.

This topic was automatically closed 90 days after the last reply. New replies are no longer allowed.