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fix(fms): fix prediction crash due to invalid thrust limit prediction #9719

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Jan 9, 2025
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fix(fms): fix prediction crash due to invalid thrust limit prediction #9719

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86c60e7
Fix thrust limit prediction
BlueberryKing Jan 5, 2025
7122a85
Merge branch 'master' into fix-predictions
Benjozork Jan 9, 2025
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47 changes: 17 additions & 30 deletions fbw-a32nx/src/systems/fmgc/src/flightplanning/A320AircraftConfig.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -57,36 +57,23 @@ const engineModelParams: EngineModelParameters = {
numberOfEngines: 2,
fuelBurnFactor: 1.0,
cn1ClimbLimit: [
[0, 2000, 5000, 8000, 12000, 15000, 17000, 20000, 24000, 27000, 31000, 35000, 39000, 41500],
[-54.0, 71.8, 73.6, 75.5, 76.8, 78.1, 78.9, 80.1, 81.5, 81.6, 83.0, 83.6, 83.7, 83.3],
[-50.0, 72.5, 74.3, 76.2, 77.5, 78.8, 79.6, 80.9, 82.2, 82.4, 83.8, 84.4, 84.5, 84.0],
[-46.0, 73.1, 75.0, 76.9, 78.2, 79.5, 80.3, 81.6, 83.0, 83.1, 84.5, 85.1, 85.3, 84.8],
[-42.0, 73.8, 75.6, 77.6, 78.9, 80.2, 81.0, 82.3, 83.7, 83.8, 85.3, 85.9, 86.0, 85.5],
[-38.0, 74.4, 76.3, 78.2, 79.6, 80.9, 81.7, 83.0, 84.4, 84.6, 86.0, 86.6, 86.7, 86.3],
[-34.0, 75.0, 76.9, 78.9, 80.3, 81.6, 82.4, 83.7, 85.1, 85.3, 86.7, 87.3, 87.5, 87.0],
[-30.0, 75.7, 77.6, 79.6, 80.9, 82.2, 83.1, 84.4, 85.8, 86.0, 87.5, 88.1, 88.2, 87.7],
[-26.0, 76.3, 78.2, 80.2, 81.6, 82.9, 83.8, 85.1, 86.5, 86.7, 88.2, 88.8, 88.9, 88.4],
[-22.0, 76.9, 78.8, 80.9, 82.2, 83.6, 84.4, 85.8, 87.2, 87.4, 88.9, 89.5, 89.6, 89.1],
[-18.0, 77.5, 79.5, 81.5, 82.9, 84.2, 85.1, 86.5, 87.9, 88.1, 89.6, 90.2, 90.0, 89.5],
[-14.0, 78.1, 80.1, 82.1, 83.5, 84.9, 85.8, 87.1, 88.6, 88.8, 90.3, 90.0, 89.2, 88.7],
[-10.0, 78.7, 80.7, 82.8, 84.2, 85.6, 86.4, 87.8, 89.3, 89.5, 91.0, 89.2, 88.4, 87.9],
[-6.0, 79.3, 81.3, 83.4, 84.8, 86.2, 87.1, 88.5, 90.0, 90.1, 91.1, 88.5, 87.7, 87.1],
[-2.0, 79.9, 81.9, 84.0, 85.5, 86.8, 87.7, 89.1, 90.6, 90.8, 90.2, 87.7, 86.9, 86.4],
[2.0, 80.5, 82.5, 84.6, 86.1, 87.5, 88.4, 89.8, 91.3, 90.3, 89.5, 87.0, 86.2, 85.6],
[6.0, 81.1, 83.1, 85.3, 86.7, 88.1, 89.0, 90.4, 90.5, 89.5, 88.8, 86.3, 85.5, 84.9],
[10.0, 81.6, 83.7, 85.9, 87.3, 88.7, 89.7, 90.0, 89.6, 88.7, 88.1, 85.6, 84.8, 84.2],
[14.0, 82.2, 84.3, 86.5, 87.9, 89.4, 89.3, 89.1, 88.7, 87.9, 87.5, 84.8, 83.9, 83.3],
[18.0, 82.8, 84.9, 87.1, 88.5, 88.6, 88.4, 88.3, 87.9, 87.2, 86.8, 86.8, 86.8, 86.8],
[22.0, 83.4, 85.5, 86.9, 88.0, 87.8, 87.7, 87.5, 87.2, 86.5, 86.1, 86.1, 86.1, 86.1],
[26.0, 83.9, 85.7, 86.2, 87.2, 87.1, 87.0, 86.8, 86.5, 85.8, 85.4, 85.4, 85.4, 85.4],
[30.0, 84.5, 84.9, 85.4, 86.5, 86.4, 86.3, 86.1, 85.8, 85.1, 85.1, 85.1, 85.1, 85.1],
[34.0, 83.8, 84.2, 84.7, 85.8, 85.7, 85.6, 85.5, 85.1, 85.1, 85.1, 85.1, 85.1, 85.1],
[38.0, 83.0, 83.4, 83.9, 85.1, 85.0, 84.9, 84.8, 84.8, 84.8, 84.8, 84.8, 84.8, 84.8],
[42.0, 82.2, 82.6, 83.1, 84.4, 84.4, 84.3, 84.3, 84.3, 84.3, 84.3, 84.3, 84.3, 84.3],
[46.0, 81.4, 81.8, 82.4, 83.7, 83.7, 83.7, 83.7, 83.7, 83.7, 83.7, 83.7, 83.7, 83.7],
[50.0, 80.6, 81.1, 81.6, 83.0, 83.0, 83.0, 83.0, 83.0, 83.0, 83.0, 83.0, 83.0, 83.0],
[54.0, 79.9, 80.4, 80.4, 80.4, 80.4, 80.4, 80.4, 80.4, 80.4, 80.4, 80.4, 80.4, 80.4],
[58.0, 79.2, 79.2, 79.2, 79.2, 79.2, 79.2, 79.2, 79.2, 79.2, 79.2, 79.2, 79.2, 79.2],
[-2000, 30.8, 56.87, 80.28, 72.0],
[2000, 20.99, 48.157, 82.58, 74.159],
[5000, 16.139, 43.216, 84.642, 75.737],
[8000, 7.342, 38.17, 86.835, 77.338],
[10000, 4.051, 34.518, 88.183, 77.999],
[10000.1, 4.051, 34.518, 87.453, 77.353],
[12000, 0.76, 30.865, 88.303, 78.66],
[15000, -4.859, 25.039, 89.748, 79.816],
[17000, -9.934, 19.813, 90.668, 80.895],
[20000, -15.822, 13.676, 92.106, 81.894],
[24000, -22.75, 6.371, 93.651, 82.716],
[27000, -29.105, -0.304, 93.838, 83.26],
[29314, -32.049, -3.377, 93.502, 82.962],
[31000, -34.98, -6.452, 95.392, 84.11],
[35000, -45.679, -17.15, 96.104, 85.248],
[39000, -45.679, -17.15, 96.205, 84.346],
[41500, -45.679, -17.15, 95.676, 83.745],
],
table1502: [
[0, 0, 0.2, 0.9],
Expand Down
53 changes: 17 additions & 36 deletions fbw-a32nx/src/systems/fmgc/src/flightplanning/A380AircraftConfig.ts
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Expand Up @@ -55,43 +55,24 @@ const engineModelParams: EngineModelParameters = {
maxThrust: 80_213,
numberOfEngines: 4,
fuelBurnFactor: 1.33,
/**
* Maximum N1 in CLB thrust
* @param i row index (tat) in steps of 4°C
* @param j col index (pressure altitude, ft)
* @returns Corrected N1 (CN1)
*/
cn1ClimbLimit: [
[0, 2000, 5000, 8000, 12000, 15000, 17000, 20000, 24000, 27000, 31000, 35000, 39000, 41500],
[-54, 82.6, 84.6, 86.8, 88.3, 89.7, 90.7, 92.1, 94.6, 96.2, 99.5, 102.0, 104.1, 105.5],
[-50, 82.6, 84.6, 86.8, 88.3, 89.7, 90.7, 92.1, 94.6, 96.2, 99.5, 102.0, 104.1, 105.5],
[-46, 82.6, 84.6, 86.8, 88.3, 89.7, 90.7, 92.1, 94.6, 96.2, 99.5, 102.0, 104.1, 105.5],
[-42, 82.6, 84.6, 86.8, 88.3, 89.7, 90.7, 92.1, 94.6, 96.2, 99.5, 102.0, 104.1, 105.5],
[-38, 82.6, 84.6, 86.8, 88.3, 89.7, 90.7, 92.1, 94.6, 96.2, 99.5, 102.0, 104.1, 105.5],
[-34, 82.6, 84.6, 86.8, 88.3, 89.7, 90.7, 92.1, 94.6, 96.2, 99.5, 102.0, 104.1, 105.5],
[-30, 82.6, 84.6, 86.8, 88.3, 89.7, 90.7, 92.1, 94.6, 96.2, 99.5, 102.0, 104.1, 105.5],
[-26, 82.6, 84.6, 86.8, 88.3, 89.7, 90.7, 92.1, 94.6, 96.2, 99.5, 102.0, 104.1, 105.5],
[-22, 82.6, 84.6, 86.8, 88.3, 89.7, 90.7, 92.1, 94.6, 96.2, 99.5, 102.0, 104.1, 105.5],
[-18, 82.6, 84.6, 86.8, 88.3, 89.7, 90.7, 92.1, 94.6, 96.2, 99.5, 102.0, 104.1, 105.5],
[-14, 82.6, 84.6, 86.8, 88.3, 89.7, 90.7, 92.1, 94.6, 96.2, 99.5, 100.5, 102.5, 103.9],
[-10, 82.6, 84.6, 86.8, 88.3, 89.7, 90.7, 92.1, 94.6, 96.2, 99.5, 99.1, 100.9, 102.3],
[-6, 82.6, 84.6, 86.8, 88.3, 89.7, 90.7, 92.1, 94.6, 96.2, 99.5, 97.7, 99.3, 100.6],
[-2, 82.6, 84.6, 86.8, 88.3, 89.7, 90.7, 92.1, 94.6, 96.2, 98.1, 96.2, 97.7, 99.0],
[2, 82.6, 84.6, 86.8, 88.3, 89.7, 90.7, 92.1, 94.6, 94.8, 96.6, 94.8, 96.1, 97.3],
[6, 82.6, 84.6, 86.8, 88.3, 89.7, 90.7, 92.1, 93.2, 93.5, 95.1, 93.3, 94.5, 95.7],
[10, 82.6, 84.6, 86.8, 88.3, 89.7, 90.7, 90.8, 91.8, 92.1, 93.7, 91.9, 92.9, 94.0],
[14, 82.6, 84.6, 86.8, 88.3, 89.7, 89.4, 89.6, 90.4, 90.8, 92.2, 90.5, 91.3, 92.4],
[18, 82.6, 84.6, 86.8, 88.3, 88.5, 88.2, 88.3, 89.1, 89.4, 90.7, 89.0, 89.7, 90.7],
[22, 82.6, 84.6, 85.6, 87.1, 87.3, 87.0, 87.0, 87.7, 88.1, 89.2, 87.6, 88.1, 89.1],
[26, 82.6, 84.6, 84.5, 85.9, 86.0, 85.8, 85.7, 86.3, 86.7, 87.8, 86.1, 86.5, 87.4],
[30, 82.6, 83.4, 83.3, 84.7, 84.8, 84.6, 84.4, 84.9, 85.4, 86.3, 84.7, 84.9, 85.8],
[34, 81.4, 82.1, 82.1, 83.5, 83.5, 83.3, 83.2, 83.5, 84.0, 84.8, 83.3, 83.3, 84.2],
[38, 80.2, 80.8, 80.9, 82.3, 82.3, 82.1, 81.9, 82.2, 82.6, 83.4, 81.8, 81.6, 82.5],
[42, 79.0, 79.6, 79.7, 81.1, 81.1, 80.9, 80.6, 80.8, 81.3, 81.9, 80.4, 80.0, 80.9],
[46, 77.8, 78.3, 78.5, 79.9, 79.8, 79.7, 79.3, 79.4, 79.9, 80.4, 78.9, 78.4, 79.2],
[50, 76.6, 77.0, 77.3, 78.7, 78.6, 78.5, 78.1, 78.0, 78.6, 78.9, 77.5, 76.8, 77.6],
[54, 75.4, 75.7, 76.2, 77.5, 77.3, 77.2, 76.8, 76.6, 77.2, 77.5, 76.1, 75.2, 75.9],
[58, 74.2, 74.5, 75.0, 76.3, 76.1, 76.0, 75.5, 75.3, 75.9, 76.0, 74.6, 73.6, 74.3],
[-2000, 30.8, 56.87, 80.28, 72.0],
[2000, 20.99, 48.157, 82.58, 74.159],
[5000, 16.139, 43.216, 84.642, 75.737],
[8000, 7.342, 38.17, 86.835, 77.338],
[10000, 4.051, 34.518, 88.183, 77.999],
[10000.1, 4.051, 34.518, 87.453, 77.353],
[12000, 0.76, 30.865, 88.303, 78.66],
[15000, -4.859, 25.039, 89.748, 79.816],
[17000, -9.934, 19.813, 90.668, 80.895],
[20000, -15.822, 13.676, 92.106, 81.894],
[24000, -22.75, 6.371, 94.588, 83.543],
[27000, -29.105, -0.304, 96.203, 85.358],
[29314, -32.049, -3.377, 96.82, 85.906],
[31000, -34.98, -6.452, 98.568, 86.909],
[35000, -45.679, -17.15, 100.977, 89.57],
[39000, -45.679, -17.15, 103.085, 90.377],
[41500, -45.679, -17.15, 104.509, 91.476],
],
/**
* Table 1502 - CN2 vs CN1 @ Mach 0, 0.2, 0.9
Expand Down
9 changes: 7 additions & 2 deletions fbw-a32nx/src/systems/fmgc/src/flightplanning/AircraftConfigTypes.ts
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Expand Up @@ -97,8 +97,13 @@ export interface EngineModelParameters {

/**
* Maximum corrected N1 in CLB thrust
* @param i row index (tat) in steps of 4°C
* @param j col index (pressure altitude, ft)
* Each row represents a different altitude and the corresponding engine thrust
* limits. The columns in each row represent the following parameters:
* 1. Altitude (in feet)
* 2. Corner Point (CP) - the temperature below which the engine can operate at full thrust without any restrictions.
* 3. Limit Point (LP) - the temperature above which the engine thrust starts to be limited.
* 4. CN1 Flat - the engine's N1 fan speed limit at the CP temperature.
* 5. CN1 Last - the engine's N1 fan speed limit at the LP temperature.
* @returns Corrected N1 (CN1)
*/
cn1ClimbLimit: readonly (readonly number[])[];
Expand Down
58 changes: 56 additions & 2 deletions fbw-a32nx/src/systems/fmgc/src/guidance/vnav/EngineModel.ts
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Expand Up @@ -176,7 +176,61 @@ export class EngineModel {
return cn1;
}

static getClimbThrustCorrectedN1(parameters: EngineModelParameters, altitude: Feet, totalAirTemperature: number) {
return EngineModel.tableInterpolation(parameters.cn1ClimbLimit, totalAirTemperature, altitude);
static getClimbThrustCorrectedN1(
parameters: EngineModelParameters,
pressureAltitude: Feet,
outsideTemperature: Celsius,
): number {
let loAltRow = 0;
let hiAltRow = 0;

// Check for over/under flows. Else, find top row value
if (pressureAltitude >= parameters.cn1ClimbLimit[parameters.cn1ClimbLimit.length - 1][0]) {
hiAltRow = parameters.cn1ClimbLimit.length - 1;
loAltRow = parameters.cn1ClimbLimit.length - 1;
} else {
hiAltRow = parameters.cn1ClimbLimit.reduce((acc, val, idx) => {
return val[0] <= pressureAltitude ? idx + 1 : acc;
}, 0);
loAltRow = hiAltRow - 1;
}

// Define key table variables and interpolation
const cp = Common.interpolate(
pressureAltitude,
parameters.cn1ClimbLimit[loAltRow][0],
parameters.cn1ClimbLimit[hiAltRow][0],
parameters.cn1ClimbLimit[loAltRow][1],
parameters.cn1ClimbLimit[hiAltRow][1],
);
const lp = Common.interpolate(
pressureAltitude,
parameters.cn1ClimbLimit[loAltRow][0],
parameters.cn1ClimbLimit[hiAltRow][0],
parameters.cn1ClimbLimit[loAltRow][2],
parameters.cn1ClimbLimit[hiAltRow][2],
);
const cn1Flat = Common.interpolate(
pressureAltitude,
parameters.cn1ClimbLimit[loAltRow][0],
parameters.cn1ClimbLimit[hiAltRow][0],
parameters.cn1ClimbLimit[loAltRow][3],
parameters.cn1ClimbLimit[hiAltRow][3],
);
const cn1Last = Common.interpolate(
pressureAltitude,
parameters.cn1ClimbLimit[loAltRow][0],
parameters.cn1ClimbLimit[hiAltRow][0],
parameters.cn1ClimbLimit[loAltRow][4],
parameters.cn1ClimbLimit[hiAltRow][4],
);

if (outsideTemperature <= cp) {
return cn1Flat;
}

const m = (cn1Last - cn1Flat) / (lp - cp);
const b = cn1Last - m * lp;
return m * outsideTemperature + b;
}
}
9 changes: 2 additions & 7 deletions fbw-a32nx/src/systems/fmgc/src/guidance/vnav/climb/ClimbPathBuilder.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -457,12 +457,7 @@ export class ClimbPathBuilder {
): StepResults {
const { zeroFuelWeight, managedClimbSpeedMach, tropoPause } = this.computationParametersObserver.get();

const averageCas = (initialSpeed + speedTarget) / 2;
const averageClimbSpeedMach = Math.min(
managedClimbSpeedMach,
this.atmosphericConditions.computeMachFromCas(altitude, averageCas),
);
const totalAirTemperature = this.atmosphericConditions.totalAirTemperatureFromMach(altitude, averageClimbSpeedMach);
const staticAirTemperature = this.atmosphericConditions.predictStaticAirTemperatureAtAltitude(altitude);

return Predictions.speedChangeStep(
config,
Expand All @@ -472,7 +467,7 @@ export class ClimbPathBuilder {
speedTarget,
managedClimbSpeedMach,
managedClimbSpeedMach,
EngineModel.getClimbThrustCorrectedN1(config.engineModelParameters, altitude, totalAirTemperature),
EngineModel.getClimbThrustCorrectedN1(config.engineModelParameters, altitude, staticAirTemperature),
zeroFuelWeight,
fuelWeight,
0,
Expand Down
39 changes: 9 additions & 30 deletions fbw-a32nx/src/systems/fmgc/src/guidance/vnav/climb/ClimbStrategy.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -132,7 +132,7 @@ export class VerticalSpeedStrategy implements ClimbStrategy, DescentStrategy {
headwindComponent: WindComponent,
config: AircraftCtlSurfcConfiguration = DEFAULT_AIRCRAFT_CONTROL_SURFACE_CONFIG,
): StepResults {
const { zeroFuelWeight, perfFactor, tropoPause, managedClimbSpeedMach } = this.observer.get();
const { zeroFuelWeight, perfFactor, tropoPause } = this.observer.get();

const computedMach = Math.min(this.atmosphericConditions.computeMachFromCas(initialAltitude, initialSpeed), mach);

Expand All @@ -142,8 +142,6 @@ export class VerticalSpeedStrategy implements ClimbStrategy, DescentStrategy {
this.acConfig.engineModelParameters,
this.atmosphericConditions,
initialAltitude,
initialSpeed,
managedClimbSpeedMach,
)
: EngineModel.getIdleCorrectedN1(
this.acConfig.engineModelParameters,
Expand Down Expand Up @@ -261,7 +259,7 @@ export class FlightPathAngleStrategy implements ClimbStrategy, DescentStrategy {
headwindComponent: WindComponent,
config: AircraftCtlSurfcConfiguration = DEFAULT_AIRCRAFT_CONTROL_SURFACE_CONFIG,
): StepResults {
const { zeroFuelWeight, perfFactor, tropoPause, managedClimbSpeedMach } = this.observer.get();
const { zeroFuelWeight, perfFactor, tropoPause } = this.observer.get();

const computedMach = Math.min(this.atmosphericConditions.computeMachFromCas(initialAltitude, initialSpeed), mach);
const predictedN1 =
Expand All @@ -270,8 +268,6 @@ export class FlightPathAngleStrategy implements ClimbStrategy, DescentStrategy {
this.acConfig.engineModelParameters,
this.atmosphericConditions,
initialAltitude,
initialSpeed,
managedClimbSpeedMach,
)
: EngineModel.getIdleCorrectedN1(
this.acConfig.engineModelParameters,
Expand Down Expand Up @@ -319,7 +315,7 @@ export class ClimbThrustClimbStrategy implements ClimbStrategy {
headwindComponent: WindComponent,
config: AircraftCtlSurfcConfiguration = DEFAULT_AIRCRAFT_CONTROL_SURFACE_CONFIG,
): StepResults {
const { zeroFuelWeight, tropoPause, perfFactor, managedClimbSpeedMach } = this.observer.get();
const { zeroFuelWeight, tropoPause, perfFactor } = this.observer.get();

return Predictions.altitudeStep(
this.acConfig,
Expand All @@ -331,8 +327,6 @@ export class ClimbThrustClimbStrategy implements ClimbStrategy {
this.acConfig.engineModelParameters,
this.atmosphericConditions,
(initialAltitude + finalAltitude) / 2,
speed,
managedClimbSpeedMach,
),
zeroFuelWeight,
fuelOnBoard,
Expand All @@ -355,21 +349,15 @@ export class ClimbThrustClimbStrategy implements ClimbStrategy {
headwindComponent: WindComponent,
config: AircraftCtlSurfcConfiguration = DEFAULT_AIRCRAFT_CONTROL_SURFACE_CONFIG,
): StepResults {
const { zeroFuelWeight, tropoPause, perfFactor, managedClimbSpeedMach } = this.observer.get();
const { zeroFuelWeight, tropoPause, perfFactor } = this.observer.get();

return Predictions.distanceStep(
this.acConfig,
initialAltitude,
distance,
speed,
mach,
getClimbThrustCorrectedN1Limit(
this.acConfig.engineModelParameters,
this.atmosphericConditions,
initialAltitude,
speed,
managedClimbSpeedMach,
),
getClimbThrustCorrectedN1Limit(this.acConfig.engineModelParameters, this.atmosphericConditions, initialAltitude),
zeroFuelWeight,
fuelOnBoard,
headwindComponent.value,
Expand All @@ -391,21 +379,15 @@ export class ClimbThrustClimbStrategy implements ClimbStrategy {
headwindComponent: WindComponent,
config: AircraftCtlSurfcConfiguration = DEFAULT_AIRCRAFT_CONTROL_SURFACE_CONFIG,
): StepResults {
const { zeroFuelWeight, perfFactor, tropoPause, managedClimbSpeedMach } = this.observer.get();
const { zeroFuelWeight, perfFactor, tropoPause } = this.observer.get();

return Predictions.altitudeStepWithSpeedChange(
this.acConfig,
initialAltitude,
initialSpeed,
finalSpeed,
mach,
getClimbThrustCorrectedN1Limit(
this.acConfig.engineModelParameters,
this.atmosphericConditions,
initialAltitude,
initialSpeed,
managedClimbSpeedMach,
),
getClimbThrustCorrectedN1Limit(this.acConfig.engineModelParameters, this.atmosphericConditions, initialAltitude),
zeroFuelWeight,
fuelOnBoard,
headwindComponent.value,
Expand All @@ -423,11 +405,8 @@ function getClimbThrustCorrectedN1Limit(
engineModelParameters: EngineModelParameters,
atmosphericConditions: AtmosphericConditions,
altitude: Feet,
speed: Knots,
maxMach: Mach,
) {
const climbSpeedMach = Math.min(maxMach, atmosphericConditions.computeMachFromCas(altitude, speed));
const estimatedTat = atmosphericConditions.totalAirTemperatureFromMach(altitude, climbSpeedMach);
const staticAirTemperature = atmosphericConditions.predictStaticAirTemperatureAtAltitude(altitude);

return EngineModel.getClimbThrustCorrectedN1(engineModelParameters, altitude, estimatedTat);
return EngineModel.getClimbThrustCorrectedN1(engineModelParameters, altitude, staticAirTemperature);
}
12 changes: 2 additions & 10 deletions fbw-a32nx/src/systems/fmgc/src/guidance/vnav/cruise/CruisePathBuilder.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -262,15 +262,7 @@ export class CruisePathBuilder {
const { zeroFuelWeight, cruiseAltitude, managedCruiseSpeedMach, tropoPause } =
this.computationParametersObserver.get();

const averageCas = (speed + finalSpeed) / 2;
const averageClimbSpeedMach = Math.min(
managedCruiseSpeedMach,
this.atmosphericConditions.computeMachFromCas(cruiseAltitude, averageCas),
);
const totalAirTemperature = this.atmosphericConditions.totalAirTemperatureFromMach(
cruiseAltitude,
averageClimbSpeedMach,
);
const staticAirTemperature = this.atmosphericConditions.predictStaticAirTemperatureAtAltitude(cruiseAltitude);

return Predictions.speedChangeStep(
config,
Expand All @@ -280,7 +272,7 @@ export class CruisePathBuilder {
finalSpeed,
managedCruiseSpeedMach,
managedCruiseSpeedMach,
EngineModel.getClimbThrustCorrectedN1(config.engineModelParameters, cruiseAltitude, totalAirTemperature),
EngineModel.getClimbThrustCorrectedN1(config.engineModelParameters, cruiseAltitude, staticAirTemperature),
zeroFuelWeight,
remainingFuelOnBoard,
headwind.value,
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5 changes: 2 additions & 3 deletions fbw-a32nx/src/systems/fmgc/src/guidance/vnav/takeoff/TakeoffPathBuilder.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -100,13 +100,12 @@ export class TakeoffPathBuilder {
const startingAltitude = lastCheckpoint.altitude;
const midwayAltitude = (startingAltitude + accelerationAltitude) / 2;

const v2PlusTenMach = this.atmosphericConditions.computeMachFromCas(midwayAltitude, speed);
const estimatedTat = this.atmosphericConditions.totalAirTemperatureFromMach(midwayAltitude, v2PlusTenMach);
const staticAirTemperature = this.atmosphericConditions.predictStaticAirTemperatureAtAltitude(midwayAltitude);

const predictedN1 = EngineModel.getClimbThrustCorrectedN1(
config.engineModelParameters,
midwayAltitude,
estimatedTat,
staticAirTemperature,
);

const { fuelBurned, distanceTraveled, timeElapsed } = Predictions.altitudeStep(
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