fix(a380x/flight model): Fix for bounced landings and increase in pitch inertia

[donstim]

This PR is intended to: 1) fix the issue of bouncing on relatively low sink rate landings, and 2) further reduce pitch sensitivity.

Summary of Changes

Changes to:

1. Flap aero parameters
2. Wheel contact point compression parameters
3. Pitch inertia
4. Elevator effectiveness.

Screenshots (if necessary)

References

Videos used as examples of pitch responsiveness during takeoff rotation: https://youtu.be/uEgw2p8J0ZA?si=eu9N1JcnQBBqIac5&t=746, https://youtu.be/pHui34_ODnc?si=jNcT-ePdqAmbGgNQ&t=57

Additional context

Discord username (if different from GitHub): donbikes

Testing instructions

1. Test landing in various conditions to confirm good landing flare characteristics and determine susceptibility to bounced landings. (For the latter it may be helpful to record videos with the dev mode speed and wheels debug windows open to 1) determine the touchdown rate of descent. and 2) see if the wheels bounce off the runway.)
2. Confirm during takeoff that pitch response to initial pitch control movement during rotation is not immediate.
3. Confirm this PR does not "break anything" flight model-wise on a full flight (doesn't have to be a long one).

How to download the PR for QA

Every new commit to this PR will cause new A32NX and A380X artifacts to be created, built, and uploaded.

1. Make sure you are signed in to GitHub
2. Click on the Checks tab on the PR
3. On the left side, find and click on the PR Build tab
4. Click on either flybywire-aircraft-a320-neo or flybywire-aircraft-a380-842 download link at the bottom of the page

[HaoXian0136]

The wing does not drop

[donstim]

The wing does not drop

Thanks for the report.

[donstim]

Should be fixed now (thanks to @Saschl)

[Saschl]

Quality Assurance Tester/Trainee Report

Discord Username : saschl
Object of testing : #10804
Aircraft : A380X
Simulator : 2024
Tier of Testing : 2
Date : 09/07/2026

Testing Process:

1. Test landing in various conditions to confirm good landing flare characteristics and determine susceptibility to bounced landings. (For the latter it may be helpful to record videos with the dev mode speed and wheels debug windows open to 1) determine the touchdown rate of descent. and 2) see if the wheels bounce off the runway.)

Tendency to bounce is reduced, I however see a slight pitch up after the wheels touch the ground and letting go of the stick. Could also be my bad landing skills.

2026-07-09.17-52-01.-.Trim.mp4

Hard landing that bounced

bouncy.mp4

"smoother one"

smooth.mp4

2. Confirm during takeoff that pitch response to initial pitch control movement during rotation is not immediate.

Feels "heavier" and does not overreact imo

3. Confirm this PR does not "break anything" flight model-wise on a full flight (doesn't have to be a long one).

Could not observe any bad behaviour in normal flight

Testing Results:
Passed

Negatives:

Tendency to pitch up on a landing with neutral stick, but that was also present before and might as well be due to my landing "technique"

Conclusions:

Media:

[donstim]

Tendency to pitch up after touchdown is due to the effect of ground spoiler deployment. This effect is reduced by this PR when landing with proper flare technique, but needs to be fully addressed by a separate flight control system PR.

Has been fixed by #10902