CD/VD/FD/DF reworked perf. arc calc

README.md

@@ -55,6 +55,8 @@ LGAV BIBE1L SID (Cycle 2507, ID 10654)
 ### Instructions
 
 - From preceding fix, fly along `Course` until reaching `Alt`.
+- If preceding fix was overfly, offset outbound `Course` to end of turn (tangent).
+- Earliest leg terminations is at point of tangent.
 
 ### Units
 
@@ -84,6 +86,8 @@ LGAV BIBE2F SID (Cycle 2507, ID 10657)
 
 - From preceding fix, fly along `Course` until reaching `Distance` from the navaid identified by
   `NavID`.
+- If preceding fix was overfly, offset outbound `Course` to end of turn (tangent).
+- Earliest leg terminations is at point of tangent.
 
 ### Units
 
@@ -116,6 +120,7 @@ LGAV BIBE2F SID (Cycle 2507, ID 10657)
 
 - From preceding fix, fly `Course` to the fix identified by (`WptID`, `WptLat`, `WptLon`) *or* 
   (`NavID`, `NavLat`, `NavLon`, `NavDist`, `NavBear`).
+- If preceding fix was overfly, continue turn until intercept `Course`, then continue on `Course`.
 
 ### Units
 
@@ -208,7 +213,7 @@ LGAV KOR1D SID (Cycle 2507, ID 10679)
 - `IsFlyOver`: Boolean indicating if fix is a mandatory fly over.
 
 
-## Fix to Altitude (FA)
+## Track from Fix to Altitude (FA)
 
 ### Example
 
@@ -227,6 +232,8 @@ LGAV BIBE2F SID (Cycle 2507, ID 10657)
 
 - From the fix identified by (`WptID`, `WptLat`, `WptLon`) *or*
   (`NavID`, `NavLat`, `NavLon`, `NavDist`, `NavBear`), fly `Course` until reaching `Alt`.
+- If preceding fix was overfly, continue turn until intercept `Course`, then continue on `Course`.
+- Earliest leg terminations is at point of intercept.
 
 ### Units
 
@@ -261,6 +268,9 @@ LIED CAR6F SID (Cycle 2507, ID 11798)
 
 - From the fix identified by (`WptID`, `WptLat`, `WptLon`) *or*
   (`NavID`, `NavLat`, `NavLon`, `NavDist`, `NavBear`), fly `Course` until reaching `Distance`.
+- If preceding fix was overfly, continue turn until intercept `Course`, then continue on `Course`.
+- Earliest leg terminations is at point of intercept.
+
 
 ### Units
 
@@ -292,8 +302,10 @@ LGAV BIBE2T SID (Cycle 2507, ID 10659)
 ### Instructions
 
 - From the fix identified by (`WptID`, `WptLat`, `WptLon`) *or*
-  (`NavID`, `NavLat`, `NavLon`, `NavDist`, `NavBear`), fly `Course` until
-  reaching `Distance` from navaid identified by `NavID`.
+  (`NavID`, `NavLat`, `NavLon`, `NavDist`, `NavBear`), fly `Course` until reaching `Distance` from
+  navaid identified by `NavID`.
+- If preceding fix was overfly, continue turn until intercept `Course`, then continue on `Course`.
+- Earliest leg terminations is at point of intercept.
 
 ### Units
 

TODO.md

@@ -0,0 +1,2 @@
+- Revisit CA/FA/VA legs
+- Revisit CD/FD/VD/FC legs

browser/src/App.tsx

@@ -8,7 +8,9 @@ import L from "leaflet";
 
 const parser = await Parser.instance();
 
-const terminals = [10394, 10395, 10475, 10480, 10482, 10485, 10653, 10654];
+const terminals = [
+  10394, 10395, 10475, 10480, 10482, 10485, 10653, 10654, 10657, 10659,
+];
 
 function App() {
   const [selectedTerminal, setSelectedTerminal] = useState(terminals[0]);
@@ -106,6 +108,7 @@ function App() {
           display: "flex",
           flexDirection: "column",
           gap: "10px",
+          width: "max-content",
         }}
       >
         {terminals.map((terminal) => (
@@ -113,14 +116,18 @@ function App() {
             key={terminal}
             style={{
               display: "flex",
-              gap: "10px",
+              flexDirection: "column",
               background: selectedTerminal === terminal ? "#eeeeee" : undefined,
             }}
+            onClick={() => setSelectedTerminal(terminal)}
           >
-            <pre>ID {terminal}</pre>
-            <button onClick={() => setSelectedTerminal(terminal)}>
-              Select
-            </button>
+            <span style={{ whiteSpace: "nowrap" }}>
+              {(() => {
+                const t = parser.terminals.find(({ ID }) => ID === terminal);
+                return `${t?.ICAO} - ${t?.FullName}`;
+              })()}
+            </span>
+            <pre>({terminal})</pre>
           </div>
         ))}
       </div>

browser/src/parser/node.ts

@@ -14,4 +14,4 @@ fetch = async (path: string) => {
 
 const parser = await Parser.instance();
 
-console.log(JSON.stringify(await parser.parse(10654)));
+console.log(JSON.stringify(await parser.parse(10657)));

browser/src/parser/parser.ts

@@ -14,25 +14,29 @@ import { TerminatorsVD } from "./terminators/VD.ts";
 import { TerminatorsRF } from "./terminators/RF.ts";
 import { TerminatorsCA } from "./terminators/CA.ts";
 import { TerminatorsDF } from "./terminators/DF.ts";
+import { TerminatorsFD } from "./terminators/FD.ts";
+import { TerminatorsFA } from "./terminators/FA.ts";
+import { TerminatorsCD } from "./terminators/CD.ts";
 
 class Parser {
   private static _instance: Parser;
 
-  private waypoints: Waypoint[];
-  private runways: Runway[];
-  private terminals: Terminal[];
+  private _waypoints: Waypoint[];
+  private _runways: Runway[];
+  private _terminals: Terminal[];
 
   public static AC_SPEED = 250;
-  public static AC_VS = 1500;
+  public static AC_BANK = 30;
+  public static AC_VS = 1400;
 
   private constructor(
     waypoints: Waypoint[],
     runways: Runway[],
     terminals: Terminal[]
   ) {
-    this.waypoints = waypoints;
-    this.runways = runways;
-    this.terminals = terminals;
+    this._waypoints = waypoints;
+    this._runways = runways;
+    this._terminals = terminals;
   }
 
   public static instance = async () => {
@@ -47,6 +51,16 @@ class Parser {
     return Parser._instance;
   };
 
+  public get terminals() {
+    return this._terminals;
+  }
+  public get waypoints() {
+    return this._waypoints;
+  }
+  public get runways() {
+    return this._runways;
+  }
+
   public parse = async (terminalID: number) => {
     // Private functions
     /**
@@ -132,9 +146,15 @@ class Parser {
           update(fixToAdd, lineToAdd);
           break;
         }
-        case "CD":
-          console.error("Unknown TrackCode", leg.TrackCode);
+        case "CD": {
+          const [fixToAdd, lineToAdd] = TerminatorsCD(
+            leg as CDTerminalEntry,
+            previousFix,
+            lastCourse
+          );
+          update(fixToAdd, lineToAdd);
           break;
+        }
         case "CF": {
           const [fixToAdd, lineToAdd] = TerminatorsCF(
             leg as CFTerminalEntry,
@@ -174,11 +194,27 @@ class Parser {
           update(fixToAdd, lineToAdd);
           break;
         }
-        case "FA":
+        case "FA": {
+          const [fixToAdd, lineToAdd] = TerminatorsFA(
+            leg as FATerminalEntry,
+            previousFix,
+            lastCourse
+          );
+          update(fixToAdd, lineToAdd);
+          break;
+        }
         case "FC":
-        case "FD":
           console.error("Unknown TrackCode", leg.TrackCode);
           break;
+        case "FD": {
+          const [fixToAdd, lineToAdd] = TerminatorsFD(
+            leg as FDTerminalEntry,
+            previousFix,
+            lastCourse
+          );
+          update(fixToAdd, lineToAdd);
+          break;
+        }
         case "FM": {
           const [fixToAdd, lineToAdd] = TerminatorsFM(
             leg as FMTerminalEntry,

browser/src/parser/pathGenerators/generatePerformanceArc.ts

@@ -1,10 +1,12 @@
 import * as geolib from "geolib";
 import Parser from "../parser.ts";
+import { computeTurnRate } from "../utils/computeTurnRate.ts";
 
 /**
  * @param crsIntoEndpoint Course into arc endpoint
  * @param crsFromOrigin Course from arc origin point
  * @param start Arc origin point
+ * @param speed Speed within arc
  * @param turnDir Turn direction
  * @returns Line segments
  */
@@ -12,12 +14,15 @@ export const generatePerformanceArc = (
   crsIntoEndpoint: number,
   crsFromOrigin: number,
   start: NavFix,
+  speed: number,
   turnDir?: TurnDirection
 ) => {
+  const turnRate = computeTurnRate(speed, Parser.AC_BANK);
+
   const line: LineSegment[] = [[start.longitude, start.latitude]];
 
   // Check if there even is an arc
-  if (crsIntoEndpoint !== crsFromOrigin) {
+  if (!crsFromOrigin.equal(crsIntoEndpoint)) {
     // Turn Dir
     if (!turnDir || turnDir === "E") {
       let prov = crsFromOrigin - crsIntoEndpoint;
@@ -26,15 +31,18 @@ export const generatePerformanceArc = (
     }
 
     // Generate arc
-    while (crsFromOrigin !== crsIntoEndpoint) {
+    while (!crsFromOrigin.equal(crsIntoEndpoint)) {
+      let time = 0;
       if (turnDir === "R") {
         const delta = (crsIntoEndpoint - crsFromOrigin).normaliseDegrees();
-        crsFromOrigin += delta < 1 ? delta : 1;
-        crsFromOrigin = crsFromOrigin.normaliseDegrees();
+        const increment = delta < 1 ? delta : 1;
+        crsFromOrigin = (crsFromOrigin + increment).normaliseDegrees();
+        time = increment / turnRate;
       } else {
         const delta = (crsFromOrigin - crsIntoEndpoint).normaliseDegrees();
-        crsFromOrigin -= delta < 1 ? delta : 1;
-        crsFromOrigin = crsFromOrigin.normaliseDegrees();
+        const increment = delta < 1 ? delta : 1;
+        crsFromOrigin = (crsFromOrigin - increment).normaliseDegrees();
+        time = increment / turnRate;
       }
 
       const arcFix = geolib.computeDestinationPoint(
@@ -42,7 +50,7 @@ export const generatePerformanceArc = (
           latitude: line.at(-1)![1],
           longitude: line.at(-1)![0],
         },
-        ((start.speed ?? Parser.AC_SPEED) / 3600).toMetre(),
+        ((speed / 3600) * time).toMetre(),
         crsFromOrigin
       );
 

browser/src/parser/pathGenerators/handleTurnAtFix.ts

@@ -1,6 +1,7 @@
 import * as geolib from "geolib";
 import { generateTangentArc } from "./generateTangentArc.ts";
 import { generatePerformanceArc } from "./generatePerformanceArc.ts";
+import Parser from "../parser.ts";
 
 /**
  * @param crsIntoEndpoint Course into endpoint
@@ -35,6 +36,7 @@ export const handleTurnAtFix = (
       crsIntoIntercept,
       crsFromOrigin,
       start,
+      start.speed ? start.speed : Parser.AC_SPEED,
       turnDir
     );
 

browser/src/parser/terminators/CA.ts

@@ -14,7 +14,7 @@ export const TerminatorsCA = (
       (
         ((leg.Alt.parseAltitude() - (previousFix.altitude ?? 0)) /
           Parser.AC_VS) *
-        (Parser.AC_SPEED / 60)
+        ((previousFix.speed ? previousFix.speed : Parser.AC_SPEED) / 60)
       ).toMetre(),
       leg.Course.toTrue(previousFix)
     ),

browser/src/parser/terminators/CD.ts

@@ -0,0 +1,67 @@
+import * as geolib from "geolib";
+import { computeSpeed } from "../utils/computeSpeed.ts";
+import { generatePerformanceArc } from "../pathGenerators/generatePerformanceArc.ts";
+
+// NOTE: Distance not adjusted for altitude in this demo
+export const TerminatorsCD = (
+  leg: CDTerminalEntry,
+  previousFix: NavFix,
+  lastCourse: number
+): [NavFix?, LineSegment[]?] => {
+  const navaid = {
+    latitude: leg.NavLat,
+    longitude: leg.NavLon,
+  };
+  const speed = computeSpeed(leg, previousFix);
+
+  let line: LineSegment[] = [];
+  if (previousFix.isFlyOver) {
+    const crsIntoEndpoint = leg.Course.toTrue(previousFix);
+
+    line = generatePerformanceArc(
+      crsIntoEndpoint,
+      lastCourse,
+      previousFix,
+      speed,
+      leg.TurnDir
+    );
+  } else {
+    line.push([previousFix.longitude, previousFix.latitude]);
+  }
+
+  const arcEnd = { latitude: line.at(-1)![1], longitude: line.at(-1)![0] };
+  if (line.length > 1) {
+    lastCourse = geolib.getGreatCircleBearing(
+      {
+        latitude: line.at(-2)![1],
+        longitude: line.at(-2)![0],
+      },
+      arcEnd
+    );
+  }
+
+  const crsToNavaid = geolib.getGreatCircleBearing(arcEnd, navaid);
+  const distToNavaid = geolib.getDistance(arcEnd, navaid);
+  let remainingDistance = leg.Distance.toMetre();
+  // Navaid behind us
+  if (Math.abs(crsToNavaid - lastCourse) > 90) {
+    remainingDistance -= distToNavaid;
+  }
+  // Navaid in front of us
+  else {
+    remainingDistance = distToNavaid - remainingDistance;
+  }
+  const targetFix: NavFix = {
+    ...geolib.computeDestinationPoint(arcEnd, remainingDistance, lastCourse),
+    name: leg.Distance.toString(),
+    isFlyOver: true,
+    altitude: leg.Alt ? leg.Alt.parseAltitude() : previousFix.altitude,
+    speed: computeSpeed(leg, previousFix),
+    speedConstraint: leg.SpeedLimit,
+    altitudeConstraint: leg.Alt,
+  };
+
+  line.push([targetFix.longitude, targetFix.latitude]);
+
+  return [targetFix, line];
+};

browser/src/parser/terminators/DF.ts

@@ -1,6 +1,6 @@
 import * as geolib from "geolib";
 import { computeSpeed } from "../utils/computeSpeed.ts";
-import Parser from "../parser.ts";
+import { generatePerformanceArc } from "../pathGenerators/generatePerformanceArc.ts";
 
 export const TerminatorsDF = (
   leg: DFTerminalEntry,
@@ -8,58 +8,35 @@ export const TerminatorsDF = (
   lastCourse: number,
   waypoint?: Waypoint
 ): [NavFix?, LineSegment[]?] => {
+  const speed = computeSpeed(leg, previousFix);
+
   const targetFix: NavFix = {
     latitude: leg.WptLat,
     longitude: leg.WptLon,
     name: waypoint?.Ident ?? undefined,
     isFlyOver: leg.IsFlyOver,
     altitude: leg.Alt ? leg.Alt.parseAltitude() : previousFix.altitude,
-    speed: computeSpeed(leg, previousFix),
+    speed: speed,
     speedConstraint: leg.SpeedLimit,
     altitudeConstraint: leg.Alt,
   };
 
-  const line: LineSegment[] = [[previousFix.longitude, previousFix.latitude]];
-
+  let line: LineSegment[] = [];
   if (previousFix.isFlyOver) {
     const crsIntoEndpoint = geolib.getGreatCircleBearing(
       previousFix,
       targetFix
     );
 
-    // Check if there even is an arc
-    if (crsIntoEndpoint !== lastCourse) {
-      // Turn Dir
-      if (!leg.TurnDir || leg.TurnDir === "E") {
-        let prov = lastCourse - crsIntoEndpoint;
-        prov = prov > 180 ? prov - 360 : prov <= -180 ? prov + 360 : prov;
-        leg.TurnDir = prov > 0 ? "L" : "R";
-      }
-
-      // Generate arc
-      while (lastCourse !== crsIntoEndpoint) {
-        if (leg.TurnDir === "R") {
-          const delta = (crsIntoEndpoint - lastCourse).normaliseDegrees();
-          lastCourse += delta < 1 ? delta : 1;
-          lastCourse = lastCourse.normaliseDegrees();
-        } else {
-          const delta = (lastCourse - crsIntoEndpoint).normaliseDegrees();
-          lastCourse -= delta < 1 ? delta : 1;
-          lastCourse = lastCourse.normaliseDegrees();
-        }
-
-        const arcFix = geolib.computeDestinationPoint(
-          {
-            latitude: line.at(-1)![1],
-            longitude: line.at(-1)![0],
-          },
-          ((previousFix.speed ?? Parser.AC_SPEED) / 3600).toMetre(),
-          lastCourse
+    line = generatePerformanceArc(
+      crsIntoEndpoint,
+      lastCourse,
+      previousFix,
+      speed,
+      leg.TurnDir
     );
-
-        line.push([arcFix.longitude, arcFix.latitude]);
-      }
-    }
+  } else {
+    line.push([previousFix.longitude, previousFix.latitude]);
   }
 
   line.push([targetFix.longitude, targetFix.latitude]);

browser/src/parser/terminators/FA.ts

@@ -0,0 +1,39 @@
+import * as geolib from "geolib";
+import { handleTurnAtFix } from "../pathGenerators/handleTurnAtFix.ts";
+import { computeSpeed } from "../utils/computeSpeed.ts";
+import Parser from "../parser.ts";
+
+export const TerminatorsFA = (
+  leg: FATerminalEntry,
+  previousFix: NavFix,
+  lastCourse: number
+): [NavFix?, LineSegment[]?] => {
+  const targetFix: NavFix = {
+    ...geolib.computeDestinationPoint(
+      { latitude: leg.WptLat, longitude: leg.WptLon },
+      (
+        ((leg.Alt.parseAltitude() - (previousFix.altitude ?? 0)) /
+          Parser.AC_VS) *
+        ((previousFix.speed ? previousFix.speed : Parser.AC_SPEED) / 60)
+      ).toMetre(),
+      leg.Course.toTrue(previousFix)
+    ),
+    name: leg.Alt,
+    isFlyOver: true,
+    altitude: leg.Alt ? leg.Alt.parseAltitude() : previousFix.altitude,
+    speed: computeSpeed(leg, previousFix),
+    speedConstraint: leg.SpeedLimit,
+    altitudeConstraint: leg.Alt,
+  };
+
+  const line = handleTurnAtFix(
+    leg.Course.toTrue(previousFix),
+    leg.Course.toTrue(previousFix),
+    lastCourse,
+    previousFix,
+    targetFix,
+    leg.TurnDir
+  );
+
+  return [targetFix, line];
+};

browser/src/parser/terminators/FD.ts

@@ -0,0 +1,71 @@
+import * as geolib from "geolib";
+import { computeSpeed } from "../utils/computeSpeed.ts";
+import { generatePerformanceArc } from "../pathGenerators/generatePerformanceArc.ts";
+
+// NOTE: Distance not adjusted for altitude in this demo
+export const TerminatorsFD = (
+  leg: FDTerminalEntry,
+  previousFix: NavFix,
+  lastCourse: number
+): [NavFix?, LineSegment[]?] => {
+  const refFix = {
+    latitude: leg.WptLat,
+    longitude: leg.WptLon,
+  };
+  const navaid = {
+    latitude: leg.NavLat,
+    longitude: leg.NavLon,
+  };
+  const speed = computeSpeed(leg, previousFix);
+
+  let line: LineSegment[] = [];
+  if (previousFix.isFlyOver) {
+    const crsIntoEndpoint = leg.Course.toTrue(refFix);
+
+    line = generatePerformanceArc(
+      crsIntoEndpoint,
+      lastCourse,
+      previousFix,
+      speed,
+      leg.TurnDir
+    );
+  } else {
+    line.push([previousFix.longitude, previousFix.latitude]);
+  }
+
+  const arcEnd = { latitude: line.at(-1)![1], longitude: line.at(-1)![0] };
+  if (line.length > 1) {
+    lastCourse = geolib.getGreatCircleBearing(
+      {
+        latitude: line.at(-2)![1],
+        longitude: line.at(-2)![0],
+      },
+      arcEnd
+    );
+  }
+
+  const crsToNavaid = geolib.getGreatCircleBearing(arcEnd, navaid);
+  const distToNavaid = geolib.getDistance(arcEnd, navaid);
+  let remainingDistance = leg.Distance.toMetre();
+  // Navaid behind us
+  if (Math.abs(crsToNavaid - lastCourse) > 90) {
+    remainingDistance -= distToNavaid;
+  }
+  // Navaid in front of us
+  else {
+    remainingDistance = distToNavaid - remainingDistance;
+  }
+  const targetFix: NavFix = {
+    ...geolib.computeDestinationPoint(arcEnd, remainingDistance, lastCourse),
+    name: leg.Distance.toString(),
+    isFlyOver: true,
+    altitude: leg.Alt ? leg.Alt.parseAltitude() : previousFix.altitude,
+    speed: computeSpeed(leg, previousFix),
+    speedConstraint: leg.SpeedLimit,
+    altitudeConstraint: leg.Alt,
+  };
+
+  line.push([targetFix.longitude, targetFix.latitude]);
+
+  return [targetFix, line];
+};

browser/src/parser/terminators/TF.ts

@@ -39,6 +39,7 @@ export const TerminatorsTF = (
       }
 
       // Generate arc
+      let condition = false;
       do {
         if (leg.TurnDir === "R") {
           const delta = (crsIntoEndpoint - lastCourse).normaliseDegrees();
@@ -55,14 +56,22 @@ export const TerminatorsTF = (
             latitude: line.at(-1)![1],
             longitude: line.at(-1)![0],
           },
-          ((previousFix.speed ?? Parser.AC_SPEED) / 3600).toMetre(),
+          (
+            (previousFix.speed ? previousFix.speed : Parser.AC_SPEED) / 3600
+          ).toMetre(),
           lastCourse
         );
 
         line.push([arcFix.longitude, arcFix.latitude]);
 
         crsIntoEndpoint = geolib.getGreatCircleBearing(arcFix, targetFix);
-      } while (crsIntoEndpoint > trackIntoEndpoint);
+
+        if (leg.TurnDir === "R") {
+          condition = crsIntoEndpoint > trackIntoEndpoint;
+        } else {
+          condition = crsIntoEndpoint < trackIntoEndpoint;
+        }
+      } while (condition);
     }
   }
 

browser/src/parser/terminators/VA.ts

@@ -15,7 +15,7 @@ export const TerminatorsVA = (
       (
         ((leg.Alt.parseAltitude() - (previousFix.altitude ?? 0)) /
           Parser.AC_VS) *
-        (Parser.AC_SPEED / 60)
+        ((previousFix.speed ? previousFix.speed : Parser.AC_SPEED) / 60)
       ).toMetre(),
       leg.Course.toTrue(previousFix)
     ),

browser/src/parser/terminators/VD.ts

@@ -1,19 +1,59 @@
 import * as geolib from "geolib";
-import { handleTurnAtFix } from "../pathGenerators/handleTurnAtFix.ts";
 import { computeSpeed } from "../utils/computeSpeed.ts";
+import { generatePerformanceArc } from "../pathGenerators/generatePerformanceArc.ts";
 
 // NOTE: No wind adjustments to be made, no clue how *that* would draw
+// NOTE: Distance not adjusted for altitude in this demo
 export const TerminatorsVD = (
   leg: VDTerminalEntry,
   previousFix: NavFix,
   lastCourse: number
 ): [NavFix?, LineSegment[]?] => {
-  const targetFix: NavFix = {
-    ...geolib.computeDestinationPoint(
+  const navaid = {
+    latitude: leg.NavLat,
+    longitude: leg.NavLon,
+  };
+  const speed = computeSpeed(leg, previousFix);
+
+  let line: LineSegment[] = [];
+  if (previousFix.isFlyOver) {
+    const crsIntoEndpoint = leg.Course.toTrue(previousFix);
+
+    line = generatePerformanceArc(
+      crsIntoEndpoint,
+      lastCourse,
       previousFix,
-      leg.Distance.toMetre(),
-      leg.Course.toTrue(previousFix)
-    ),
+      speed,
+      leg.TurnDir
+    );
+  } else {
+    line.push([previousFix.longitude, previousFix.latitude]);
+  }
+
+  const arcEnd = { latitude: line.at(-1)![1], longitude: line.at(-1)![0] };
+  if (line.length > 1) {
+    lastCourse = geolib.getGreatCircleBearing(
+      {
+        latitude: line.at(-2)![1],
+        longitude: line.at(-2)![0],
+      },
+      arcEnd
+    );
+  }
+
+  const crsToNavaid = geolib.getGreatCircleBearing(arcEnd, navaid);
+  const distToNavaid = geolib.getDistance(arcEnd, navaid);
+  let remainingDistance = leg.Distance.toMetre();
+  // Navaid behind us
+  if (Math.abs(crsToNavaid - lastCourse) > 90) {
+    remainingDistance -= distToNavaid;
+  }
+  // Navaid in front of us
+  else {
+    remainingDistance = distToNavaid - remainingDistance;
+  }
+  const targetFix: NavFix = {
+    ...geolib.computeDestinationPoint(arcEnd, remainingDistance, lastCourse),
     name: leg.Distance.toString(),
     isFlyOver: true,
     altitude: leg.Alt ? leg.Alt.parseAltitude() : previousFix.altitude,
@@ -22,14 +62,7 @@ export const TerminatorsVD = (
     altitudeConstraint: leg.Alt,
   };
 
-  const line = handleTurnAtFix(
-    leg.Course.toTrue(previousFix),
-    leg.Course.toTrue(previousFix),
-    lastCourse,
-    previousFix,
-    targetFix,
-    leg.TurnDir
-  );
+  line.push([targetFix.longitude, targetFix.latitude]);
 
   return [targetFix, line];
 };

browser/src/parser/utils/computeTurnRate.ts

@@ -0,0 +1,3 @@
+export const computeTurnRate = (speed: number, bank: number) => {
+  return (1091 * Math.tan(bank.toRadians())) / speed;
+};

browser/src/parser/utils/extensions.ts

@@ -25,6 +25,9 @@ Number.prototype.toTrue = function (fix) {
 Number.prototype.toMetre = function () {
   return (this as number) * 1852.0;
 };
+Number.prototype.equal = function (other: number) {
+  return Math.abs((this as number) - other) < 0.1;
+};
 
 String.prototype.parseAltitude = function () {
   switch (this.length) {

browser/src/types/extensions.d.ts

@@ -25,6 +25,10 @@ export declare global {
      * @returns Value converted from nmi to metres
      */
     toMetre: () => number;
+    /**
+     * @returns True if delta is less than 0.1
+     */
+    equal: (other: number) => boolean;
   }
 
   interface String {

browser/src/types/terminators/CD.d.ts

@@ -0,0 +1,6 @@
+export declare global {
+  type CDTerminalEntry = Required<
+    Pick<TerminalEntry, "NavID" | "NavLat" | "NavLon" | "Course" | "Distance">
+  > &
+    TerminalEntry;
+}

browser/src/types/terminators/FA.d.ts

@@ -0,0 +1,18 @@
+export declare global {
+  type FATerminalEntry = Required<
+    Pick<
+      TerminalEntry,
+      | "WptID"
+      | "WptLat"
+      | "WptLon"
+      | "NavID"
+      | "NavLat"
+      | "NavLon"
+      | "NavBear"
+      | "NavDist"
+      | "Course"
+      | "Alt"
+    >
+  > &
+    TerminalEntry;
+}

browser/src/types/terminators/FD.d.ts

@@ -0,0 +1,18 @@
+export declare global {
+  type FDTerminalEntry = Required<
+    Pick<
+      TerminalEntry,
+      | "WptID"
+      | "WptLat"
+      | "WptLon"
+      | "NavID"
+      | "NavLat"
+      | "NavLon"
+      | "NavBear"
+      | "NavDist"
+      | "Course"
+      | "Distance"
+    >
+  > &
+    TerminalEntry;
+}