Altitude suddenly increases when lowering flaps

I’m sure things are working correctly, but when lowering my flaps a notch as I land, my altitude suddenly increases. I use Navigraph charts to help determine the proper altitude at certain distances from the airport, and the increase in altitude throws that off. I often have to overcompensate to get back down to where I need to be.

Any suggestions on how to smooth out that process? Should I use throttle more to control speed? At which point should flaps be lowered, as well as landing gear?

Flying a Beechcraft King Air, but it happens with any turboprop I fly. On Xbox Series X with Hotas One.

Pitching up when you lower the flaps is very common. You just need to anticipate it and make the appropriate trim correction if you’re hand flying.


This happens with all aircraft, it’s aerodynamics.
Lowering flaps gives you more lift, that’s the reason for them.
At low speeds, such as on approach, you need more lift.
You need to be lowering them at the correct speeds, and if flying manually, you will have to trim the plane after each position you lower them to.
The exact opposite happens upon retracting them!


Flaps are lowered to increase lift when flying slow (i.e. to land), you need to adjust trim and/or speed to compensate


I do no what happens in real world flying however I get the same effect in the sim. I anticipate the effect reduce the throttle and force the nose down to counteract it. It only lasts for a few seconds before it stabilises and I can adjust trim and throttle to remain on the GP.

Whenever you lower flap, you must also use a coordinated nose-down pitch control input to prevent the aircraft ballooning up off the established glipepath trajectory.

This happens in all aircraft, some more pronounced, some less.

As the flaps travel, push the nose down a little. Keep practicing and get to know how much nose down is required and what timing to use when lowering flap. In some aircraft the effect is almost instant, while for others there is a short delay. Again, keep practicing to get to know the timing of the pushing the nose forwards.

Some aircraft require very little throttle input to maintain the correct approach speed, while others may require a bit of power added to counteract the drag of deployed flaps.

Keep working at it and you’ll figure out what control inputs work… and enjoy the learning :slight_smile:

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In the sim the altitude increase with flaps down is really exaggerated.

Know the speed limit of each detent. Problem solved.

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I used to tell my passenger (when flying in the C150E on a hot day) “Express Elevator Up!” once I reached rotation (Vr) speed, and pulled in 10 degrees of flaps. The little airplane shot up like a bottle rocket… well, maybe not quite. :slight_smile:

So… you can use that extra lift to your advantage sometimes. Just remember to push over so you don’t get too slow at the top of the ascent.

Note that the effect of lowering flaps also depends on the wing position of the aircraft (or at least it should), in relation to the COG. A low wing aircraft may experience a pitch down when flaps are added (although may still have an increased lift). Some aircraft have trim compensation systems to counteract the ballooning effect.

Anticipation is the solution - use evelvator inputs (Push forward as you are deploying flaps and trim once on the desired attitude and glide path). With practice this should be a coordinated action.

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Or you can be lazy and cheat, In the 208 I’ll fly close to my destination, I then turn on the AP, set the altimeter for the appropriate height, when that settles in I lower my airspeed to the approach speed I want, wait again for the plane to settle, then I switch off the AP and do my final and landing. Works real well once you get the hang of it. It even works in a tube the same way…

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Absolutely true. Was just looking a another discussion with regard to the P-38 (not in MSFS) and how moving from half to full flaps causes a rather severe pitch down effect. There is a great thread posted here that expands on some aerodynamic theory… worth a read.

The recently released Kodiak is very sensitive to CG; if you trim it for takeoff like it’s a C172 you’ll quite likely end up stalling and rolling left rather severely. That particular aircraft needs a neutral or pitch down trim on takeoff to keep from rotating straight into a stall.

Thanks to all for the informative responses!


Flaps create lift or drag, in which basically drag is a byproduct of lift. So, whenever you are deploying flaps, the airplane will always tend to have the tendency of pitching the nose up regardless if it is a GA aircraft or commercial airliner unless you are flying an airbus. I have experienced that so many times whenever I deploy flaps in the real aircraft. It is always going to happen even with idle power.

'What is was taught in flight school was to anticipate the nose wanting to pitch up by smoothly applying forward pressure on the yoke and trimming the aircraft very slightly to help it keep it nose down. You can expect that basically for every degree of notch you are lowering the flaps. Just anticipate it, put forward pressure and it will help keep the nose down.

LOL – so you could say “You use your AP to Trim the Plane” … not so sure how that would work out to be such a good idea in RL :upside_down_face:


Maybe depends on the airplane. I fly a Shorts Skyvan occasionally and when we add first flaps we‘re at a pitch attitude of 5-7 degrees. The Skyvan is a high wing twin prop aircraft blowing additional prop wash over wing and flaps, hence the increase of lift is significant, the added drag above CG lifts the nose further, you have to actively push the nose down to make sure you don‘t climb. Second flaps is not that significant anymore, as you‘re much slower and not in the process of slowing down anymore but in a constant descent.

Single engine prop aircraft are less prone for this behaviour but still, fowler flaps add lift. Split flaps for example like in the T6 or VL3 (speaking of sim aircraft) mostly or only add drag.

Why stop there? Just turn on the AI copilot and let them land so you can go grab a tinny…:wink:

I threw my co-pilot outta the plane years ago, I fly alone from GA to Tubes I fly alone, except for this one time when I took off in the 208 (yesterday) in a 32 mpg cross wind and the neither would get in the plane. :stuck_out_tongue_winking_eye:
Oh well I had a picture where the pilot and co-pilot were to slow to show up in the plane during flight, must be on the other install, there’s a snap in the what did you do today thread

On airliners, when on the approach path, the Pilot Flying asks for the flaps detent according to the speed, so that precisely what you describe does not happen (sudden lift), the procedure is as follows:

  • Pilot flying: Flaps 10

  • Pilot not flying: Speed check… Flaps 10
    That sequence is invariable allowing both pilots to ensure the flaps are lowered at the correct speed.
    Don’t forget that lowering your flaps at too fast a speed may end up with structural damage as well!

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