EXT Power and Parking brake logic A350

777Driver · December 25, 2025 at 11:56 AM

For a future update: A request for EXT power logic to be tied to weight on wheels instead of parking brake In real world ops there are number of reasons why the parking brake would be off when at the gate, one of which is hot brakes after landing. I released the parking brake, the aircraft went straight to batts and disconnected EXT.

aguschimi04 · December 25, 2025 at 7:48 PM

Quote from 777Driver

For a future update: A request for EXT power logic to be tied to weight on wheels instead of parking brake In real world ops there are number of reasons why the parking brake would be off when at the gate, one of which is hot brakes after landing. I released the parking brake, the aircraft went straight to batts and disconnected EXT.

How do you have working brake temp in the A350? I tried a RTO and the temperature doesn’t rise.

777Driver · December 25, 2025 at 8:24 PM

Only the smaller airbus aircraft have working brake temp logic. I added the logic myself to the A350 using the below cooling schedule. The devs said they may add their own working version in a future update.

Btw, if you look at the code, there is a lot of amazing stuff going on behind the scenes with this A350 (quite a few things are disabled) it has the potential for a lot of expansion if the devs so choose.

Below table is for Brake fans off

AeRodri · December 31, 2025 at 6:32 AM

Quote from 777Driver

Only the smaller airbus aircraft have working brake temp logic. I added the logic myself to the A350 using the below cooling schedule. The devs said they may add their own working version in a future update.
Btw, if you look at the code, there is a lot of amazing stuff going on behind the scenes with this A350 (quite a few things are disabled) it has the potential for a lot of expansion if the devs so choose.
Below table is for Brake fans off

Would you mind sharing with us how and where you exactly added the logic into the A350? I think your improvement has quite an interesting truth to it.

Thank you in advance.

777Driver · December 31, 2025 at 1:01 PM

I added some basic code into a separate system.tmd in the Aerofly documents folder, this talks to the main system.tmd - Tbh I wouldn't suggest messing around with this stuff unless you know what you are doing. The devs said they may add this officially at some point in the future

Display Spoiler

<[file][][]
<[modelmanager][][]
<[pointer_list_tmuniverse][DynamicObjects][]

// --- DYNAMIC BRAKE TEMPS (Kelvin) ---
// Replace the 12 BrakeTemperature constants with everything below.

<[constant][BrakeTempAmbientK][] <[string8][Input][288.15]> > // 15C baseline
<[constant][BrakeCoolingFactor][] <[string8][Input][0.0002]> > // tune cooling
<[constant][BrakeHeatUpFactor][] <[string8][Input][0.008]> > // tune heating
<[constant][BrakeDownForceFactor][] <[string8][Input][0.0000065]> >
<[constant][BrakeCoolingWithFan][] <[string8][Input][0.0006]> >

// Fan-based cooling select
<[multiplexer][BrakeCoolingFactorEffective][]
<[string8][InputSelect][BrakeFansOn.Output]>
<[string8][Inputs][ BrakeCoolingFactor.Output BrakeCoolingWithFan.Output ]>
>

// Airborne cooling multiplier (set to 1.0 to disable)
<[constant][BrakeCoolingInAirMultiplier][] <[string8][Input][2.5]> >

<[multiplexer][BrakeCoolingAirSelect][]
<[string8][InputSelect][InAir.Output]>
<[string8][Inputs][ 1.0 BrakeCoolingInAirMultiplier.Output ]>
>

// Final effective cooling factor = (fan-selected cooling) * (air/ground multiplier)
<[product][BrakeCoolingFactorEffectiveFinal][]
<[string8][Inputs][ BrakeCoolingFactorEffective.Output
BrakeCoolingAirSelect.Output ]>
>
// Ground speed squared
<[product][BrakeGS2][]
<[string8][Inputs][ InertialReferenceSystem.OutputGroundSpeed
InertialReferenceSystem.OutputGroundSpeed ]>
>

// -------- LEFT --------
<[mixlinear][BrakeLeftAboveAmbient][]
<[string8][Input0][BrakeTempLeftK.Output]>
<[string8][Input1][BrakeTempAmbientK.Output]>
<[float64][Weight0][1.0]>
<[float64][Weight1][-1.0]>
>

<[product][BrakeLeftCool][]
<[string8][Inputs][ BrakeCoolingFactorEffective.Output
BrakeLeftAboveAmbient.Output ]>
>

<[maximum][LeftWheelLoadPos][]
<[string8][Inputs][ LeftWheelLoad.Output 0.0 ]>
>

<[product][BrakeLeftDownForce][]
<[string8][Inputs][ BrakeDownForceFactor.Output
LeftWheelLoadPos.Output ]>
>

<[product][BrakeLeftHeat][]
<[string8][Inputs][ BrakeHeatUpFactor.Output
BrakeLeftDownForce.Output
ServoLeftBrake.Output
BrakeGS2.Output
OnGroundSensor.Output ]>
>

<[mixlinear][BrakeLeftNet][]
<[string8][Input0][BrakeLeftHeat.Output]>
<[string8][Input1][BrakeLeftCool.Output]>
<[float64][Weight0][1.0]>
<[float64][Weight1][-1.0]>
>

// moved integral to AFTER BrakeLeftNet (so it doesn't reference forward)
<[integral][BrakeTempLeftK][]
<[string8][Input][BrakeLeftNet.Output]>
<[float64][Value][288.15]>
>

// -------- RIGHT --------
<[mixlinear][BrakeRightAboveAmbient][]
<[string8][Input0][BrakeTempRightK.Output]>
<[string8][Input1][BrakeTempAmbientK.Output]>
<[float64][Weight0][1.0]>
<[float64][Weight1][-1.0]>
>

<[product][BrakeRightCool][]
<[string8][Inputs][ BrakeCoolingFactorEffective.Output
BrakeRightAboveAmbient.Output ]>
>

<[maximum][RightWheelLoadPos][]
<[string8][Inputs][ RightWheelLoad.Output 0.0 ]>
>

<[product][BrakeRightDownForce][]
<[string8][Inputs][ BrakeDownForceFactor.Output
RightWheelLoadPos.Output ]>
>

<[product][BrakeRightHeat][]
<[string8][Inputs][ BrakeHeatUpFactor.Output
BrakeRightDownForce.Output
ServoRightBrake.Output
BrakeGS2.Output
OnGroundSensor.Output ]>
>

<[mixlinear][BrakeRightNet][]
<[string8][Input0][BrakeRightHeat.Output]>
<[string8][Input1][BrakeRightCool.Output]>
<[float64][Weight0][1.0]>
<[float64][Weight1][-1.0]>
>

// moved integral to AFTER BrakeRightNet (so it doesn't reference forward)
<[integral][BrakeTempRightK][]
<[string8][Input][BrakeRightNet.Output]>
<[float64][Value][288.15]>
>

// Feed the 12 wheel temps expected by the SD page
<[servoclassic][BrakeTemperature1][]
<[string8][Input][BrakeTempLeftK.Output]>
<[float64][Speed][1.9]>
<[float64][P1][1.0]>
<[float64][Position][288.15]>
>
<[servoclassic][BrakeTemperature2][]
<[string8][Input][BrakeTempLeftK.Output]>
<[float64][Speed][1.75]>
<[float64][P1][1.0]>
<[float64][Position][289.65]>
>
<[servoclassic][BrakeTemperature3][]
<[string8][Input][BrakeTempLeftK.Output]>
<[float64][Speed][2.12]>
<[float64][P1][1.0]>
<[float64][Position][287.35]>
>
<[servoclassic][BrakeTemperature4][]
<[string8][Input][BrakeTempLeftK.Output]>
<[float64][Speed][2.02]>
<[float64][P1][1.0]>
<[float64][Position][290.15]>
>
<[servoclassic][BrakeTemperature5][]
<[string8][Input][BrakeTempLeftK.Output]>
<[float64][Speed][2.07]>
<[float64][P1][1.0]>
<[float64][Position][286.65]>
>
<[servoclassic][BrakeTemperature6][]
<[string8][Input][BrakeTempLeftK.Output]>
<[float64][Speed][1.46]>
<[float64][P1][1.0]>
<[float64][Position][289.05]>
>

<[servoclassic][BrakeTemperature7][]
<[string8][Input][BrakeTempRightK.Output]>
<[float64][Speed][2.0]>
<[float64][P1][1.0]>
<[float64][Position][288.15]>
>
<[servoclassic][BrakeTemperature8][]
<[string8][Input][BrakeTempRightK.Output]>
<[float64][Speed][2.11]>
<[float64][P1][1.0]>
<[float64][Position][289.35]>
>
<[servoclassic][BrakeTemperature9][]
<[string8][Input][BrakeTempRightK.Output]>
<[float64][Speed][1.95]>
<[float64][P1][1.0]>
<[float64][Position][287.55]>
>
<[servoclassic][BrakeTemperature10][]
<[string8][Input][BrakeTempRightK.Output]>
<[float64][Speed][2.0]>
<[float64][P1][1.0]>
<[float64][Position][290.05]>
>
<[servoclassic][BrakeTemperature11][]
<[string8][Input][BrakeTempRightK.Output]>
<[float64][Speed][2.12]>
<[float64][P1][1.0]>
<[float64][Position][286.95]>
>
<[servoclassic][BrakeTemperature12][]
<[string8][Input][BrakeTempRightK.Output]>
<[float64][Speed][2.01]>
<[float64][P1][1.0]>
<[float64][Position][288.85]>
>

ApfelFlieger · December 31, 2025 at 2:24 PM

Quote from 777Driver

I added some basic code into a separate system.tmd in the Aerofly documents folder, this talks to the main system.tmd - Tbh I wouldn't suggest messing around with this stuff unless you know what you are doing. The devs said they may add this officially at some point in the future

In the user directory folder "aircrafts" you can create a folder with the same name as in FS 4 and then make adjustments there without intervening in the original data of the FS 4.

777Driver · December 31, 2025 at 2:46 PM

Quote from ApfelFlieger

In the user directory folder "aircrafts" you can create a folder with the same name as in FS 4 and then make adjustments there without intervening in the original data of the FS 4.

Hi Michael, I did state that in my post, I am not editing the original system.tmd. I have a a parameters & second system file in my documents folder, all modifications and overrides are made there On my PC, it is located - Documents\Aerofly FS 4\aircraft\a350_1000

ApfelFlieger · December 31, 2025 at 3:28 PM

Quote from 777Driver

Hi Michael, I did state that in my post, I am not editing the original system.tmd. I have a a parameters & second system file in my documents folder, all modifications and overrides are made there On my PC, it is located - Documents\Aerofly FS 4\aircraft\a350_1000

Thanks for your clarification😀, I had misinterpreted it🙁.