# Is flaps at 15 degrees affecting my gradient on approaches?

I’ve noticed that when I hit the spot where landing aid activates, typically at a 1,000ft, I’ll set my altitude to 0 and descent rate will automatically go to 250ft/min, I’ll then change it to something like 1,200ft/min to make up for the few seconds it was set to 250ft, but I’ll have to increase the descent rate to something like 3,000+ and not much of a difference happens, it seems the aircraft stays in the same exact position, is this from the flaps essentially holding the aircraft at the same Angle of Attack? Should I lower it to 5 degrees?

what aircraft are you flying, and what speeds? Say A32X, want to fly in flap full at round 125-140 kts depending on weights

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I am going with the 787-9 and my approaches are usually down to 160knots

If you’re going to land full flaps with a 787 then trying bringing that final approach seed down to 140-150kts, and see if that works. 160, and 30 flaps… not sure that would go well, as you’d create a decent amount of lift under the wings, ultimately, making you sort of float above the ground.

If you are as you said, 15 degrees flaps at 160, then that should be an issue, not from what I know and have tested before. Done 180kts landings with 20 degree flap config too, works fine in IF at least.

When you say “Full flaps” I think you’re saying flaps being at the highest setting, no? So I can stay at 15 as long as I bring down the speed to 150 knots? So would this mean that’s what is causing this issue with the descent? The flaps?

Yes, that is correct, at 30 degrees on the 787 series.

You should be able to land at 160kts with 15 degress flaps. But try 150kts if 160kts doesn’t work for you?

You’d be creating the same amount of lift at lower speed with increased flaps if you were staying on the glide path.
The reason you need to increase rate of descent is because your glide path is maybe 3 degrees. This is about 300ft descent per nautical mile, if you’re going faster you’ll pass 1NM sooner. Therefore your rate of descent needs to be higher to meet the same 300ft per NM.

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Flaps generate lift, the air under the wing pushes the aircraft up wards. The higher flag configuration you have, the more air gonna build up below the wing, and push the plane up, so landing with half or full flaps at a higher speed, isn’t optimal and isn’t according to the laws of physics supposed to work.

If you enter the cone, at 180kts, and then slow down to 160kts on short final with 15 degrees of flaps, just before touch down, when you flare, you should cut the throttle and be between 140-160-ish kts in the 787 as far as I’m concerned. Depending on weight and wind, the speed you land at may vary.

Ya. Kind of interesting to deal with. I will try reducing speed, but when I do it looks like the aircraft is going into a stall position, with the rear end down and the nose going up.

In the same sense, if I set trim to 15% would that give me the same results?

You will have to balance it out, your Flaps, Speed, VS, combined with the weight of your aircraft and wind. Trim is also very helpful and vital part of landing. It may also vary depending on factors such as your weight.

Try out all sort of combination, I usually land a 787-9, hat is well below MLW at around 150-155 KIAS, with 30% Trim, depending on weight and other factors. Additionally, your VS will different based on what speed you are approaching at, the angle of the glideslope, and the distance left till you touch down, from the point your entered the cone.

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Flaps generate lift and increase drag. Flaps are the secondary controls of an aircraft. They are not needed for an aircraft to operate, but they are useful to the pilot

Same principle with Trim. Not needed but is useful

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@Jack_BC thank you both.

Ya I found out just now that removing the flaps from 15 a few hundred feet from the runway, gives me that flare and an additional drop. Is there anyway to find out what degree the glide scope is for a typical airport? Or is all of this something you just have to find out by researching the airport as you if you were actually going to land there?

I think, looking at charts on the internet may be a way of finding out the angle of the glidelope, but someone else may know a beter and easier way of finding it.

I personally, would search up airport approach charts on Google. Also I’m not sure, but I’m confident SimBrief shows approach charts with glideslope angle when filing a FPL, along with the SID/STARS of course :)

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3 degrees is a standard glide slope

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If you need airport charts @me. I have fore flight and I can message you over the charts for any airport

I also have approach charts and airport diagrams etc

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I’m gonna have to take you up on that, starting now lol.

Can you do KLAX for me? I’ll take the diagram and approach chart if you have it.

I’m not sure if you need this info or not. But I typically run into runway 25R

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