My speed drops considerably before I pass 15.000 feet using VS at 2500/ft per. minute.Even though I reduce VS at 1500 the speed will contiune to drop.If you know, please tell me how can I calculate the corect VS .I will apreciate any kind of advice.Thanks

What plane?

Generally, airplanes climb like this:

  • Take off, then maintain something like 150 to 160 initially
  • Then at 1500ft AGL, reduce VS to accelerate to 250kts then adjust VS to maintain 250 kts
  • At 10,000ft, reduce VS to accelerate to 320kts then adjust VS to maintain 320 kts

If you do this, you probably won’t have the issue mentioned here.


@PilotTAR Are you using the auto throttle on auto pilot when this happens? I’ve noticed the same thing on 747 but if I set the throttle lock at the speed I want it’s pretty consistent on maintaining the speed I set.

Yes ,i usualy use autothrottle durin the climbing.I’ll try to adjust it manually .Tanks a lot


You can add one step:

@ 1500 feet reduce power and climb with 170-180 kts until 3000, then increase speed to 250 kts and clean up.

Flying like this you do a noise abatement procedure.

"Trying to upload a pic with some info regarding nose abatement procedures but I can’t :frowning: "

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Matt,I listened to your advice and I was able to maintain 320kts until 35.000feet but at that altitude the speed remind at the same value even my engines were at full power.I was flying a 747-400 using cruise altitude 35.000 feet

Your indicated airspeed will decrease the higher you go eventough you go faster and above FL280/300 you should use Mach instead