feat(fms): run predictions without v-speeds (#8921)

* Run predictions without vspeeds * Move default parameters to class * Fix inital vertical checkpoint * Use `getGrossWeight` * Do not set `blockFuel` automatically * Adapt to new `getFOB()` function --------- Co-authored-by: Andreas Guther <[email protected]>
flybywiresim · Sep 29, 2024 · 2165480 · 2165480
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diff --git a/.github/CHANGELOG.md b/.github/CHANGELOG.md
@@ -121,6 +121,7 @@
 1. [FMS] Show runway ident on lateral/vertical revision page of the missed approach point - @BlueberryKing (BlueberryKing)
 1. [ECAM] Fixed ALL ECAM Button cycling through STS page and being inconsisten on press - @Maximilian-Reuter (\_chaoz_)
 1. [CDU] Fix for EFOB calculation not pulling from block fuel prior to engine start - @PatM (Patrick Macken)
+1. [FMS] Run vertical predictions without V-speeds - @BlueberryKing (BlueberryKing)
 
 ## 0.11.0
 

diff --git a/...l_ui/Pages/VCockpit/Instruments/Airliners/FlyByWire_A320_Neo/CDU/A320_Neo_CDU_InitPage.js b/...l_ui/Pages/VCockpit/Instruments/Airliners/FlyByWire_A320_Neo/CDU/A320_Neo_CDU_InitPage.js
@@ -338,12 +338,13 @@ class CDUInitPage {
         }
     }
     static fuelPredConditionsMet(mcdu) {
-        return isFinite(mcdu.blockFuel) &&
-            isFinite(mcdu.zeroFuelWeightMassCenter) &&
-            isFinite(mcdu.zeroFuelWeight) &&
+        const fob = mcdu.getFOB();
+
+        return Number.isFinite(fob) &&
+            Number.isFinite(mcdu.zeroFuelWeightMassCenter) &&
+            Number.isFinite(mcdu.zeroFuelWeight) &&
             mcdu.flightPlanService.active && mcdu.flightPlanService.active.legCount > 0 &&
-            mcdu._zeroFuelWeightZFWCGEntered &&
-            (mcdu._blockFuelEntered || mcdu.isAnEngineOn());
+            mcdu._zeroFuelWeightZFWCGEntered;
     }
     static trySetFuelPred(mcdu) {
         if (CDUInitPage.fuelPredConditionsMet(mcdu) && !mcdu._fuelPredDone) {

diff --git a/...ml_ui/Pages/VCockpit/Instruments/Airliners/FlyByWire_A320_Neo/FMC/A32NX_FMCMainDisplay.js b/...ml_ui/Pages/VCockpit/Instruments/Airliners/FlyByWire_A320_Neo/FMC/A32NX_FMCMainDisplay.js
@@ -286,7 +286,6 @@ class FMCMainDisplay extends BaseAirliners {
         this.machToCasManualCrossoverCurve.add(0.8, 300);
         this.machToCasManualCrossoverCurve.add(0.82, 350);
 
-        this.updateFuelVars();
         this.updatePerfSpeeds();
 
         this.flightPhaseManager.init();
@@ -2062,7 +2061,11 @@ class FMCMainDisplay extends BaseAirliners {
 
     // only used by trySetRouteAlternateFuel
     isAltFuelInRange(fuel) {
-        return 0 < fuel && fuel < (this.blockFuel - this._routeTripFuelWeight);
+        if (Number.isFinite(this.blockFuel)) {
+            return 0 < fuel && fuel < (this.blockFuel - this._routeTripFuelWeight);
+        }
+
+        return 0 < fuel;
     }
 
     async trySetRouteAlternateFuel(altFuel) {
@@ -3969,10 +3972,6 @@ class FMCMainDisplay extends BaseAirliners {
         return this.navigation.getSelectedNavaids(1);
     }
 
-    updateFuelVars() {
-        this.blockFuel = SimVar.GetSimVarValue("FUEL TOTAL QUANTITY", "gallons") * SimVar.GetSimVarValue("FUEL WEIGHT PER GALLON", "kilograms") / 1000;
-    }
-
     /**
      * Set the takeoff flap config
      * @param {0 | 1 | 2 | 3 | null} flaps
@@ -4593,8 +4592,12 @@ class FMCMainDisplay extends BaseAirliners {
         return /^[+-]?\d*(?:\.\d+)?$/.test(str);
     }
 
+    /**
+     * Gets the entered zero fuel weight, or undefined if not entered
+     * @returns {number | undefined} the zero fuel weight in tonnes or undefined
+     */
     getZeroFuelWeight() {
-        return this.zeroFuelWeight * 2204.625;
+        return this.zeroFuelWeight;
     }
 
     getV2Speed() {

diff --git a/fbw-a32nx/src/systems/fmgc/src/guidance/GuidanceController.ts b/fbw-a32nx/src/systems/fmgc/src/guidance/GuidanceController.ts
@@ -41,6 +41,7 @@ const GEOMETRY_RECOMPUTATION_TIMER = 5_000;
 export interface Fmgc {
   getZeroFuelWeight(): number;
   getFOB(): number;
+  getGrossWeight(): number | null;
   getV2Speed(): Knots;
   getTropoPause(): Feet;
   getManagedClimbSpeed(): Knots;

diff --git a/fbw-a32nx/src/systems/fmgc/src/guidance/vnav/VerticalProfileComputationParameters.ts b/fbw-a32nx/src/systems/fmgc/src/guidance/vnav/VerticalProfileComputationParameters.ts
@@ -93,19 +93,21 @@ export class VerticalProfileComputationParametersObserver {
       managedDescentSpeed: this.fmgc.getManagedDescentSpeed(),
       managedDescentSpeedMach: this.fmgc.getManagedDescentSpeedMach(),
 
-      zeroFuelWeight: this.fmgc.getZeroFuelWeight(),
-      fuelOnBoard: UnitType.TONNE.convertTo(this.fmgc.getFOB(), UnitType.POUND),
-      v2Speed: this.fmgc.getV2Speed(),
+      zeroFuelWeight: this.getZeroFuelWeight(),
+      fuelOnBoard: this.getFuelOnBoard(),
+      v2Speed: this.getV2Speed(),
       tropoPause: this.fmgc.getTropoPause(),
       perfFactor: 0, // FIXME: Use actual value,
-      departureElevation: this.fmgc.getDepartureElevation() ?? 0,
+      departureElevation: this.fmgc.getDepartureElevation() ?? DefaultVerticalProfileParameters.departureElevation,
       /**
        * This differs from the altitude I use to start building the descent profile.
        * This one one is the altitude of the destination airport, the other one is the final procedure altitude.
        */
       destinationElevation: this.fmgc.getDestinationElevation(),
-      accelerationAltitude: this.fmgc.getAccelerationAltitude(),
-      thrustReductionAltitude: this.fmgc.getThrustReductionAltitude(),
+      accelerationAltitude:
+        this.fmgc.getAccelerationAltitude() ?? DefaultVerticalProfileParameters.accelerationAltitude,
+      thrustReductionAltitude:
+        this.fmgc.getThrustReductionAltitude() ?? DefaultVerticalProfileParameters.thrustReductionAltitude,
       originTransitionAltitude: this.fmgc.getOriginTransitionAltitude(),
       // We do it this way because the cruise altitude is cleared in the MCDU once you start the descent
       cruiseAltitude: this.flightPlanService.active.performanceData.cruiseFlightLevel
@@ -116,7 +118,7 @@ export class VerticalProfileComputationParametersObserver {
       flightPhase: this.fmgc.getFlightPhase(),
       preselectedClbSpeed: this.fmgc.getPreSelectedClbSpeed(),
       preselectedCruiseSpeed: this.fmgc.getPreSelectedCruiseSpeed(),
-      takeoffFlapsSetting: this.fmgc.getTakeoffFlapsSetting(),
+      takeoffFlapsSetting: this.fmgc.getTakeoffFlapsSetting() ?? DefaultVerticalProfileParameters.flapsSetting,
       estimatedDestinationFuel: UnitType.TONNE.convertTo(this.fmgc.getDestEFOB(false), UnitType.POUND),
 
       approachQnh: this.fmgc.getApproachQnh(),
@@ -145,6 +147,23 @@ export class VerticalProfileComputationParametersObserver {
     );
   }
 
+  private getV2Speed(): Knots {
+    const fmV2 = this.fmgc.getV2Speed();
+    if (Number.isFinite(fmV2)) {
+      return fmV2;
+    }
+
+    const fmGw = this.fmgc.getGrossWeight();
+    const flaps = this.fmgc.getTakeoffFlapsSetting() ?? DefaultVerticalProfileParameters.flapsSetting;
+    const departureElevation = this.fmgc.getDepartureElevation() ?? DefaultVerticalProfileParameters.departureElevation;
+
+    if (Number.isFinite(fmGw)) {
+      return DefaultVerticalProfileParameters.getV2Speed(flaps, fmGw, departureElevation);
+    }
+
+    return null;
+  }
+
   get(): VerticalProfileComputationParameters {
     return this.parameters;
   }
@@ -157,17 +176,96 @@ export class VerticalProfileComputationParametersObserver {
       this.parameters.approachSpeed > 100;
 
     const hasZeroFuelWeight = Number.isFinite(this.parameters.zeroFuelWeight);
+    const hasGrossWeight = Number.isFinite(this.fmgc.getGrossWeight());
     const hasCruiseAltitude = Number.isFinite(this.parameters.cruiseAltitude);
     const hasTakeoffParameters =
-      this.parameters.v2Speed > 0 &&
-      this.parameters.thrustReductionAltitude > 0 &&
-      this.parameters.accelerationAltitude > 0;
+      this.parameters.thrustReductionAltitude > 0 && this.parameters.accelerationAltitude > 0;
 
     return (
       (this.parameters.flightPhase > FmgcFlightPhase.Takeoff || hasTakeoffParameters) &&
       areApproachSpeedsValid &&
       hasZeroFuelWeight &&
+      hasGrossWeight &&
       hasCruiseAltitude
     );
   }
+
+  getZeroFuelWeight(): Pounds {
+    const fmZfw = this.fmgc.getZeroFuelWeight();
+
+    return Number.isFinite(fmZfw) ? UnitType.TONNE.convertTo(fmZfw, UnitType.POUND) : undefined;
+  }
+
+  getFuelOnBoard(): Pounds {
+    const fmFuelOnBoard = this.fmgc.getFOB();
+
+    return Number.isFinite(fmFuelOnBoard) ? UnitType.TONNE.convertTo(fmFuelOnBoard, UnitType.POUND) : undefined;
+  }
+}
+
+class DefaultVerticalProfileParameters {
+  static readonly accelerationAltitude = 1500;
+
+  static readonly thrustReductionAltitude = 1500;
+
+  static readonly v2Speeds: Record<number, ((m: number) => number)[]> = {
+    1: [
+      () => 126,
+      () => 126,
+      () => 126,
+      (m: number) => 126 + 0.2 * (m - 50),
+      (m: number) => 127 + m - 55,
+      (m: number) => 132 + m - 60,
+      (m: number) => 137 + m - 65,
+      (m: number) => 142 + m - 70,
+      (m: number) => 147 + m - 75,
+      () => 151,
+    ], // Conf 1 + F
+    2: [
+      () => 126,
+      () => 126,
+      () => 126,
+      () => 126,
+      (m: number) => 126 + 0.2 * (m - 55),
+      (m: number) => 127 + m - 60,
+      (m: number) => 132 + m - 65,
+      (m: number) => 137 + 0.8 * (m - 70),
+      (m: number) => 141 + m - 75,
+      () => 146,
+    ], // Conf 2
+    3: [
+      () => 125,
+      () => 125,
+      () => 125,
+      () => 125,
+      () => 125,
+      (m: number) => 125 + 0.6 * (m - 60),
+      (m: number) => 128 + 0.8 * (m - 65),
+      (m: number) => 132 + m - 70,
+      (m: number) => 137 + 0.8 * (m - 75),
+      () => 141,
+    ], // Conf 3
+  };
+
+  static readonly flapsSetting = 1;
+
+  static readonly departureElevation = 0;
+
+  static readonly destinationElevation = 0;
+
+  /**
+   * Gives the minimal V2 speed for a given configuration, gross weight and elevation.
+   * @param conf flap configuration
+   * @param fmGw gross weight in tonnes
+   * @param elevation departure elevation in feet
+   * @returns
+   */
+  static getV2Speed(conf: number, fmGw: number, elevation: number): number {
+    const massIndex = Math.ceil((Math.min(fmGw, 80) - 40) / 5);
+
+    return Math.floor(
+      DefaultVerticalProfileParameters.v2Speeds[conf][massIndex](fmGw) +
+        (conf === 2 ? Math.abs(elevation * 0.0002) : 0),
+    );
+  }
 }
diff --git a/fbw-a32nx/src/systems/fmgc/src/guidance/vnav/takeoff/TakeoffPathBuilder.ts b/fbw-a32nx/src/systems/fmgc/src/guidance/vnav/takeoff/TakeoffPathBuilder.ts
@@ -28,8 +28,8 @@ export class TakeoffPathBuilder {
 
     profile.checkpoints.push({
       reason: VerticalCheckpointReason.Liftoff,
-      distanceFromStart: 0.6,
-      secondsFromPresent: 20,
+      distanceFromStart: 0,
+      secondsFromPresent: 0,
       altitude: departureElevation,
       remainingFuelOnBoard: fuelOnBoard,
       speed: v2Speed + 10,