fix(tcas): use correct altitudes

.github/CHANGELOG.md

@@ -107,6 +107,8 @@
 1. [A380X/ENGINES] Adjust climb thrust to be more accurate - @BlueberryKing (BlueberryKing)
 1. [A380X/EWD] Show THR limit in EWD instead of N1 - @flogross89 (floridude)
 1. [A380X/FLIGHT MODEL] Fix pitchup and unrecoverable stall - - @donstim (donbikes#4084)
+1. [ATC/TCAS] Fixed TCAS failure on baro corrected altitude going invalid - @tracernz (Mike)
+1. [ATC/TCAS] Fixed TCAS slant range computation - @tracernz (Mike)
 
 ## 0.12.0
 

fbw-a32nx/src/systems/tcas/src/components/TcasComputer.ts

@@ -14,6 +14,7 @@ import {
   NXDataStore,
   UpdateThrottler,
   LocalSimVar,
+  AirDataSwitchingKnob,
 } from '@flybywiresim/fbw-sdk';
 import { Coordinates } from 'msfs-geo';
 import { TcasComponent } from '../lib/TcasComponent';
@@ -221,11 +222,7 @@ export class TcasComputer implements TcasComponent {
 
   private ppos: LatLongData; // Plane PPOS
 
-  private baroCorrectedAltitude1: Arinc429Word | null; // ADR1/2 Altitude
-
-  private adr3BaroCorrectedAltitude1: Arinc429Word | null; // ADR3 Altitude
-
-  private pressureAlt: number | null; // Pressure Altitude
+  private pressureAlt: Arinc429Word | null; // Pressure Altitude
 
   private planeAlt: number | null; // Plane Altitude
 
@@ -297,27 +294,31 @@ export class TcasComputer implements TcasComponent {
     this.verticalSpeed = SimVar.GetSimVarValue('VERTICAL SPEED', 'feet per minute');
     this.ppos.lat = SimVar.GetSimVarValue('PLANE LATITUDE', 'degree latitude');
     this.ppos.long = SimVar.GetSimVarValue('PLANE LONGITUDE', 'degree longitude');
+    this.planeAlt = SimVar.GetSimVarValue('PLANE ALTITUDE', 'feet');
 
     this.tcasPower = !!SimVar.GetSimVarValue('L:A32NX_ELEC_DC_1_BUS_IS_POWERED', 'boolean');
     this.tcasSwitchPos = SimVar.GetSimVarValue('L:A32NX_SWITCH_TCAS_Position', 'number');
     this.altRptgSwitchPos = SimVar.GetSimVarValue('L:A32NX_SWITCH_ATC_ALT', 'number');
     this.tcasThreat = SimVar.GetSimVarValue('L:A32NX_SWITCH_TCAS_Traffic_Position', 'number');
     this.xpdrStatus = SimVar.GetSimVarValue('TRANSPONDER STATE:1', 'number');
     this.activeXpdr = SimVar.GetSimVarValue('L:A32NX_TRANSPONDER_SYSTEM', 'number');
-    // workaround for altitude issues due to MSFS bug, needs to be changed to PRESSURE ALTITUDE again when solved
-    this.pressureAlt = SimVar.GetSimVarValue('INDICATED ALTITUDE:3', 'feet');
-    this.planeAlt = SimVar.GetSimVarValue('PLANE ALTITUDE', 'feet');
+
+    const alternateAirDataSourceSelect =
+      SimVar.GetSimVarValue('L:A32NX_AIR_DATA_SWITCHING_KNOB', 'enum') ===
+      (this.activeXpdr === 0 ? AirDataSwitchingKnob.Capt : AirDataSwitchingKnob.Fo);
+    this.pressureAlt = Arinc429Word.fromSimVarValue(
+      alternateAirDataSourceSelect
+        ? `L:A32NX_ADIRS_ADR_3_ALTITUDE`
+        : `L:A32NX_ADIRS_ADR_${this.activeXpdr + 1}_ALTITUDE`,
+    );
+
     const radioAlt1 = Arinc429Word.fromSimVarValue('L:A32NX_RA_1_RADIO_ALTITUDE');
     const radioAlt2 = Arinc429Word.fromSimVarValue('L:A32NX_RA_2_RADIO_ALTITUDE');
     this.radioAlt =
       (radioAlt1.isFailureWarning() || radioAlt1.isNoComputedData()) &&
       !(!radioAlt1.isNoComputedData() && radioAlt2.isFailureWarning())
         ? radioAlt2
         : radioAlt1;
-    this.baroCorrectedAltitude1 = Arinc429Word.fromSimVarValue(
-      `L:A32NX_ADIRS_ADR_${this.activeXpdr + 1}_BARO_CORRECTED_ALTITUDE_1`,
-    );
-    this.adr3BaroCorrectedAltitude1 = Arinc429Word.fromSimVarValue('L:A32NX_ADIRS_ADR_3_BARO_CORRECTED_ALTITUDE_1');
     this.trueHeading = SimVar.GetSimVarValue('PLANE HEADING DEGREES TRUE', 'degrees');
     this.isSlewActive = !!SimVar.GetSimVarValue('IS SLEW ACTIVE', 'boolean');
     this.simRate = SimVar.GetGlobalVarValue('SIMULATION RATE', 'number');
@@ -355,7 +356,7 @@ export class TcasComputer implements TcasComponent {
       this.inhibitions = Inhibit.ALL_DESC_RA;
     } else if (!this.radioAlt.isNoComputedData() && this.radioAlt.value < 1550) {
       this.inhibitions = Inhibit.ALL_INCR_DESC_RA;
-    } else if (this.pressureAlt > 39000) {
+    } else if (this.pressureAlt.value > 39000) {
       this.inhibitions = Inhibit.ALL_CLIMB_RA;
     } else {
       this.inhibitions = Inhibit.NONE;
@@ -393,12 +394,9 @@ export class TcasComputer implements TcasComponent {
 
     // Amber TCAS warning on fault (and on PFD) - 34-43-00:A24/34-43-010
     if (
-      !this.baroCorrectedAltitude1 ||
-      !this.adr3BaroCorrectedAltitude1 ||
-      !this.baroCorrectedAltitude1.isNormalOperation() ||
-      !this.adr3BaroCorrectedAltitude1.isNormalOperation() ||
+      !this.pressureAlt ||
+      (!this.pressureAlt.isNormalOperation() && !this.pressureAlt.isFunctionalTest()) ||
       this.radioAlt.isFailureWarning() ||
-      this.baroCorrectedAltitude1.value - this.adr3BaroCorrectedAltitude1.value > 300 ||
       !this.tcasPower
     ) {
       this.tcasFault.setVar(true);
@@ -417,13 +415,25 @@ export class TcasComputer implements TcasComponent {
         this.radioAlt.value <= TCAS.SENSE[3][Limits.MAX]
       ) {
         this.sensitivity.setVar(3);
-      } else if (this.pressureAlt > TCAS.SENSE[4][Limits.MIN] && this.pressureAlt <= TCAS.SENSE[4][Limits.MAX]) {
+      } else if (
+        this.pressureAlt.value > TCAS.SENSE[4][Limits.MIN] &&
+        this.pressureAlt.value <= TCAS.SENSE[4][Limits.MAX]
+      ) {
         this.sensitivity.setVar(4);
-      } else if (this.pressureAlt > TCAS.SENSE[5][Limits.MIN] && this.pressureAlt <= TCAS.SENSE[5][Limits.MAX]) {
+      } else if (
+        this.pressureAlt.value > TCAS.SENSE[5][Limits.MIN] &&
+        this.pressureAlt.value <= TCAS.SENSE[5][Limits.MAX]
+      ) {
         this.sensitivity.setVar(5);
-      } else if (this.pressureAlt > TCAS.SENSE[6][Limits.MIN] && this.pressureAlt <= TCAS.SENSE[6][Limits.MAX]) {
+      } else if (
+        this.pressureAlt.value > TCAS.SENSE[6][Limits.MIN] &&
+        this.pressureAlt.value <= TCAS.SENSE[6][Limits.MAX]
+      ) {
         this.sensitivity.setVar(6);
-      } else if (this.pressureAlt > TCAS.SENSE[7][Limits.MIN] && this.pressureAlt <= TCAS.SENSE[7][Limits.MAX]) {
+      } else if (
+        this.pressureAlt.value > TCAS.SENSE[7][Limits.MIN] &&
+        this.pressureAlt.value <= TCAS.SENSE[7][Limits.MAX]
+      ) {
         this.sensitivity.setVar(7);
       } else {
         this.sensitivity.setVar(8);
@@ -479,7 +489,7 @@ export class TcasComputer implements TcasComponent {
             traffic.alt,
             this.ppos.lat,
             this.ppos.long,
-            this.pressureAlt,
+            this.planeAlt,
           );
           const newClosureRate = ((traffic.slantDistance - newSlantDist) / (_deltaTime / 1000)) * 3600; // knots = nautical miles per hour
           traffic.closureAccel = (newClosureRate - traffic.closureRate) / (_deltaTime / 1000);

fbw-a380x/src/systems/systems-host/systems/tcas/components/LegacyTcasComputer.ts

@@ -14,6 +14,7 @@ import {
   NXDataStore,
   LocalSimVar,
   Arinc429Register,
+  AirDataSwitchingKnob,
 } from '@flybywiresim/fbw-sdk';
 import { Coordinates } from 'msfs-geo';
 import {
@@ -215,11 +216,7 @@ export class LegacyTcasComputer implements Instrument {
 
   private ppos: LatLongData; // Plane PPOS
 
-  private baroCorrectedAltitude1: Arinc429Word | null; // ADR1/2 Altitude
-
-  private adr3BaroCorrectedAltitude1: Arinc429Word | null; // ADR3 Altitude
-
-  private pressureAlt: number | null; // Pressure Altitude
+  private pressureAlt: Arinc429Word | null; // Pressure Altitude
 
   private planeAlt: number | null; // Plane Altitude
 
@@ -318,15 +315,23 @@ export class LegacyTcasComputer implements Instrument {
     this.verticalSpeed = SimVar.GetSimVarValue('VERTICAL SPEED', 'feet per minute');
     this.ppos.lat = SimVar.GetSimVarValue('PLANE LATITUDE', 'degree latitude');
     this.ppos.long = SimVar.GetSimVarValue('PLANE LONGITUDE', 'degree longitude');
+    this.planeAlt = SimVar.GetSimVarValue('PLANE ALTITUDE', 'feet');
 
     this.tcasPower =
       SimVar.GetSimVarValue('L:A32NX_ELEC_AC_ESS_BUS_IS_POWERED', 'boolean') ||
       SimVar.GetSimVarValue('L:A32NX_ELEC_AC_2_BUS_IS_POWERED', 'boolean');
     this.activeXpdr = SimVar.GetSimVarValue('L:A32NX_TRANSPONDER_SYSTEM', 'number');
     this.xpdrStatus = SimVar.GetSimVarValue(`TRANSPONDER STATE:${this.activeXpdr + 1}`, 'number');
-    // workaround for altitude issues due to MSFS bug, needs to be changed to PRESSURE ALTITUDE again when solved
-    this.pressureAlt = SimVar.GetSimVarValue('INDICATED ALTITUDE:3', 'feet');
-    this.planeAlt = SimVar.GetSimVarValue('PLANE ALTITUDE', 'feet');
+
+    const alternateAirDataSourceSelect =
+      SimVar.GetSimVarValue('L:A32NX_AIR_DATA_SWITCHING_KNOB', 'enum') ===
+      (this.activeXpdr === 0 ? AirDataSwitchingKnob.Capt : AirDataSwitchingKnob.Fo);
+    this.pressureAlt = Arinc429Word.fromSimVarValue(
+      alternateAirDataSourceSelect
+        ? `L:A32NX_ADIRS_ADR_3_ALTITUDE`
+        : `L:A32NX_ADIRS_ADR_${this.activeXpdr + 1}_ALTITUDE`,
+    );
+
     const radioAlt1 = Arinc429Word.fromSimVarValue('L:A32NX_RA_1_RADIO_ALTITUDE');
     const radioAlt2 = Arinc429Word.fromSimVarValue('L:A32NX_RA_2_RADIO_ALTITUDE');
     this.radioAlt =
@@ -335,12 +340,8 @@ export class LegacyTcasComputer implements Instrument {
         ? radioAlt2
         : radioAlt1;
 
-    this.baroCorrectedAltitude1 = Arinc429Word.fromSimVarValue(
-      `L:A32NX_ADIRS_ADR_${this.activeXpdr + 1}_BARO_CORRECTED_ALTITUDE_1`,
-    );
     const irSwitchingKnob = SimVar.GetSimVarValue('L:A32NX_ATT_HDG_SWITCHING_KNOB', 'enum');
     const irToUse = irSwitchingKnob === 1 ? this.activeXpdr + 1 : 3;
-    this.adr3BaroCorrectedAltitude1 = Arinc429Word.fromSimVarValue('L:A32NX_ADIRS_ADR_3_BARO_CORRECTED_ALTITUDE_1');
     this.irTrueheading.setFromSimVar(`L:A32NX_ADIRS_IR_${irToUse}_TRUE_HEADING`);
     this.isSlewActive = !!SimVar.GetSimVarValue('IS SLEW ACTIVE', 'boolean');
     this.simRate = SimVar.GetGlobalVarValue('SIMULATION RATE', 'number');
@@ -381,7 +382,7 @@ export class LegacyTcasComputer implements Instrument {
       this.inhibitions = Inhibit.ALL_DESC_RA;
     } else if (!this.radioAlt.isNoComputedData() && this.radioAlt.value < 1550) {
       this.inhibitions = Inhibit.ALL_INCR_DESC_RA;
-    } else if (this.pressureAlt > 39000) {
+    } else if (this.pressureAlt.value > 39000) {
       this.inhibitions = Inhibit.ALL_CLIMB_RA;
     } else {
       this.inhibitions = Inhibit.NONE;
@@ -397,12 +398,9 @@ export class LegacyTcasComputer implements Instrument {
       !this.irTrueheading ||
       !this.irTrueheading.isNormalOperation() ||
       this.irTrueheading.isNoComputedData() ||
-      !this.baroCorrectedAltitude1 ||
-      !this.adr3BaroCorrectedAltitude1 ||
-      !this.baroCorrectedAltitude1.isNormalOperation() ||
-      !this.adr3BaroCorrectedAltitude1.isNormalOperation() ||
+      !this.pressureAlt ||
+      (!this.pressureAlt.isNormalOperation() && !this.pressureAlt.isFunctionalTest()) ||
       this.radioAlt.isFailureWarning() ||
-      this.baroCorrectedAltitude1.value - this.adr3BaroCorrectedAltitude1.value > 300 ||
       !this.tcasPower
     ) {
       this.resetDisplay();
@@ -448,13 +446,25 @@ export class LegacyTcasComputer implements Instrument {
         this.radioAlt.value <= TCAS.SENSE[3][Limits.MAX]
       ) {
         this.sensitivity.setVar(3);
-      } else if (this.pressureAlt > TCAS.SENSE[4][Limits.MIN] && this.pressureAlt <= TCAS.SENSE[4][Limits.MAX]) {
+      } else if (
+        this.pressureAlt.value > TCAS.SENSE[4][Limits.MIN] &&
+        this.pressureAlt.value <= TCAS.SENSE[4][Limits.MAX]
+      ) {
         this.sensitivity.setVar(4);
-      } else if (this.pressureAlt > TCAS.SENSE[5][Limits.MIN] && this.pressureAlt <= TCAS.SENSE[5][Limits.MAX]) {
+      } else if (
+        this.pressureAlt.value > TCAS.SENSE[5][Limits.MIN] &&
+        this.pressureAlt.value <= TCAS.SENSE[5][Limits.MAX]
+      ) {
         this.sensitivity.setVar(5);
-      } else if (this.pressureAlt > TCAS.SENSE[6][Limits.MIN] && this.pressureAlt <= TCAS.SENSE[6][Limits.MAX]) {
+      } else if (
+        this.pressureAlt.value > TCAS.SENSE[6][Limits.MIN] &&
+        this.pressureAlt.value <= TCAS.SENSE[6][Limits.MAX]
+      ) {
         this.sensitivity.setVar(6);
-      } else if (this.pressureAlt > TCAS.SENSE[7][Limits.MIN] && this.pressureAlt <= TCAS.SENSE[7][Limits.MAX]) {
+      } else if (
+        this.pressureAlt.value > TCAS.SENSE[7][Limits.MIN] &&
+        this.pressureAlt.value <= TCAS.SENSE[7][Limits.MAX]
+      ) {
         this.sensitivity.setVar(7);
       } else {
         this.sensitivity.setVar(8);
@@ -510,7 +520,7 @@ export class LegacyTcasComputer implements Instrument {
             traffic.alt,
             this.ppos.lat,
             this.ppos.long,
-            this.pressureAlt,
+            this.planeAlt,
           );
           const newClosureRate = ((traffic.slantDistance - newSlantDist) / (_deltaTime / 1000)) * 3600; // knots = nautical miles per hour
           traffic.closureAccel = (newClosureRate - traffic.closureRate) / (_deltaTime / 1000);

fbw-common/src/systems/shared/src/types/SwitchingKnobs.ts

@@ -0,0 +1,23 @@
+export enum DmcSwitchingKnob {
+  Capt,
+  Norm,
+  Fo,
+}
+
+export enum EcamNdSwitchingKnob {
+  Capt,
+  Norm,
+  Fo,
+}
+
+export enum AttHdgSwitchingKnob {
+  Capt,
+  Norm,
+  Fo,
+}
+
+export enum AirDataSwitchingKnob {
+  Capt,
+  Norm,
+  Fo,
+}

fbw-common/src/systems/shared/src/types/index.ts

@@ -1,6 +1,5 @@
 // Copyright (c) 2024 FlyByWire Simulations
 // SPDX-License-Identifier: GPL-3.0
 
-import { GenericAdirsEvents } from './GenericAdirsEvents';
-
-export { GenericAdirsEvents };
+export * from './GenericAdirsEvents';
+export * from './SwitchingKnobs';