Tips for Climbing to a High Altitude

I was trying to climb to FL380 in a 737-800 and I noticed that as I got past ~FL250, the aircraft started losing airspeed. I decreased the VS so the speed can stay stable so I wouldn’t stall. Eventually, I did climb up to FL380 but I had to put full thrust on to reach my cruise speed of M.80. Any tips on what I should do next time? I want to make the climb as realistic as possible.

Keep in mind, I had normal weight


1 Like

I’m not sure if this is a bug with Infinite Flight. I especially don’t like when I go above a certain altitude and the knots change to Mach. I’m gonna get tired of FL220 when Global Flight comes out.

(Sorry, don’t have any tips.)


What was your exact VS?


Well, I’m always between about 32000ft - 41000ft. My cruise speed ends up being 454knots. I gradually reduce my VS and increase the airspeed slightly. But for a smooth climb it’s always a slow process.

1 Like

Not to get too off topic here, but where were you going at 38,000 feet? Airports aren’t really that far away to go that high. (Until global flight comes)

1 Like

From takeoff to FL180 it was 2500fpm then from 180-250 it was 1800, then I started losing speed so I gradually decreased from 1800 to a slow 200 near TOC

1 Like

It is not a bug. Mach number should be used at higher altitude.


1 Like

I was simulating a real flight from SAN-SEA. I fly as far as possible in one region and continue in the next region. It’s the best experience I can get until global comes…


When I’m on a real flight, it seems like the engine thrust stays the same the entire climb up. I was trying to simulate that but in the end, I failed

1 Like

Hmm that’s odd. I rarely go up to a altitude that high so I’m not sure. Sorry:(

1 Like

In IF knots change to Mach on the autopilot knob above FL280

Lower air density = lower airspeed?

Service ceiling of the 737-700, 800, 900 is 41000ft, good luck flying without stalling after that. Then your weight matters and also the outside temperature.

Climb to FL300 gain speed then go to FL350 gain speed go to FL380 gain speed…(i cruise at FL410)…you can’t make it direct…your wieght matters too…if you want to climb fast use N1 100/99% above FL100 use a VS of 3000 adjust when needed and as required and you’ll get up there…also depends with the type of plane…some planes are powerfull eg.Citation…you can do it direct to FL410 with ease


One more thing, majority of these aircraft are programmed to match real world specifications. So check specs. out as well.

1 Like

Simular to how I simulate a long haul flight…

You should be able to climb up to FL320 at Heavy setting without any issues, to go higher for a step climb need to reduce to fuel weight down a bit.

After passing 10000 ft I set my VS to 2500 and IAS to 305kts and then I have no problem with the climb. Works on nearly all the heavy aircraft ok.

1 Like

Depending on weight but in real life you can be climbing with Max 500-800 feet a min in the last few thousands of feet.


I do start off with a VS around 3000ft till I get to about FL170 then I reduce to 2500ft to maintain airspeed. At around FL260 I reduce to 1500ft and once at FL300, my VS stays below 1000ft till my desired cruising altitude. I do all this while keeping N1 under 90


@Mobin_A @Phoenix1 @David_Lockwood @Aernout @Slay thanks for the tips! ;)


For the 737, im not sure if you heard of this but think of 250/280/80. Obvoulsy the speed should below 250 knots below 10,000ft when you clean up the aircraft (when the flaps are fully retracted) once you go above 10,000 ft you can increase your speed to 280 knots or higher it would really depend on your CI which we dont have yet, as you climb higher you will notice your speed will decrease you now once the speed switches to mach number then you can select .79 or .80 mach and VS depends on you so you can adjust that.