G1000: VNAV descent profile + designated-altitude flight plan colouring

- CURRENT VNV PROFILE panel on the MFD flight-plan page: active VNV waypoint +
  target altitude, VS TGT (−3° path), VS REQ, V DEV, FPA, TIME TO TOD (manual
  S.64 / S.107)
- enriched the VNAV computation (vsTgt / vDev / FPA / time-to-TOD) shared by the
  PFD VnavBox
- flight-plan ALT column now shows designated (VNAV) altitudes in blue (S.105)
- new Audio Panel + earlier manual-alignment batch already in this branch

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

web/src/components/FplPage.jsx

@@ -64,6 +64,29 @@ export default function FplPage({ xp, full = false, onClose }) {
   const gs = num(values.groundspeed) * 1.94384;
   const ete = gs > 30 ? total / gs : null;
 
+  // CURRENT VNV PROFILE: descent to the next waypoint with a lower target
+  // altitude (manual S.64/107). VS TGT for a -3° path, VS REQ to make it, V DEV
+  // from the path, time-to-top-of-descent.
+  const alt = num(values.altitude);
+  let vnav = null;
+  if (gs > 40) {
+    let c = 0, pl = num(values.lat), po = num(values.lon);
+    for (let i = Math.max(1, active); i < wps.length; i++) {
+      c += distNm({ lat: pl, lon: po }, wps[i]); pl = wps[i].lat; po = wps[i].lon;
+      const t = num(wps[i].alt);
+      if (t > 0 && t < alt - 50) {
+        const tan = Math.tan((3 * Math.PI) / 180);
+        const vsTgt = -gs * tan * 101.27;
+        const vsReq = c > 0 ? (t - alt) / (c / gs * 60) : 0;
+        const vDev = alt - (t + c * 6076.12 * tan);
+        const todNm = c - (alt - t) / (6076.12 * tan);
+        vnav = { wptId: wps[i].id, tgtAlt: t, vsTgt, vsReq, vDev, fpa: 3.0, todSec: todNm > 0 ? (todNm / gs) * 3600 : 0 };
+        break;
+      }
+    }
+  }
+  const fmtSec = (s) => { const m = Math.floor(s / 60), ss = Math.round(s % 60); return `${m}:${String(ss).padStart(2, '0')}`; };
+
   return (
     <div className={`fpl ${full ? 'full' : 'win'}`}>
       <div className="fpl-head">
@@ -83,11 +106,24 @@ export default function FplPage({ xp, full = false, onClose }) {
             <span className="r-dtk">{dtk == null ? '___' : `${String(dtk).padStart(3, '0')}°`}</span>
             <span className="r-dis">{orig ? '—' : d.toFixed(1)}</span>
             <span className="r-cum">{orig ? '—' : cum.toFixed(0)}</span>
-            <span className="r-alt">{w.alt ? `${w.alt}` : '_____'}</span>
+            <span className={`r-alt ${w.alt ? 'dsgn' : ''}`}>{w.alt ? `${w.alt}FT` : '_____'}</span>
             <button className="r-del" onClick={(e) => { e.stopPropagation(); fp.remove(i); }}>✕</button>
           </div>
         ))}
       </div>
+      {full && (
+        <div className="fpl-vnav">
+          <div className="fpl-vnav-h">CURRENT VNV PROFILE</div>
+          {vnav ? (
+            <div className="fpl-vnav-grid">
+              <b>ACTIVE VNV WPT</b><span className="vwpt">{vnav.tgtAlt}<u>FT</u> at {vnav.wptId}</span>
+              <b>VS TGT</b><span>{Math.round(vnav.vsTgt)}<u>FPM</u></span><b>FPA</b><span>{vnav.fpa.toFixed(1)}°</span>
+              <b>VS REQ</b><span>{Math.round(vnav.vsReq)}<u>FPM</u></span><b>TIME TO TOD</b><span>{fmtSec(vnav.todSec)}</span>
+              <b>V DEV</b><span>{vnav.vDev >= 0 ? '+' : ''}{Math.round(vnav.vDev)}<u>FT</u></span>
+            </div>
+          ) : <div className="fpl-vnav-none">— no active VNAV profile —</div>}
+        </div>
+      )}
       <div className="fpl-entry">
         {hits.length > 0 && (
           <div className="fpl-hits">

web/src/components/PFD.jsx

@@ -58,6 +58,10 @@ function fmtEte(s) {
 }
 // VNAV: nearest downstream waypoint with a lower altitude constraint, and the
 // vertical speed required to meet it at the current groundspeed.
+// VNAV descent profile to the next waypoint that has a (lower) target altitude:
+// target VS for a -3° flight path, required VS to make the restriction, vertical
+// deviation from that path, and time-to-top-of-descent. (Manual S.64 / S.107.)
+const VNAV_FPA = 3.0; // default flight-path angle (degrees)
 function vnavInfo(V, fp) {
   const wps = fp?.waypoints || [];
   const ai = Math.max(1, Math.min(wps.length - 1, fp?.activeLeg ?? 1));
@@ -71,9 +75,16 @@ function vnavInfo(V, fp) {
     prevLat = wps[i].lat; prevLon = wps[i].lon;
     const tgt = num(wps[i].alt);
     if (tgt > 0 && tgt < alt - 50) {
+      const tan = Math.tan((VNAV_FPA * Math.PI) / 180);
       const tMin = (cum / gs) * 60;
-      const vsReq = tMin > 0 ? (tgt - alt) / tMin : 0;
-      return { wptId: wps[i].id, tgtAlt: tgt, dist: cum, vsReq };
+      const vsReq = tMin > 0 ? (tgt - alt) / tMin : 0;        // fpm to make the fix
+      const vsTgt = -gs * tan * 101.27;                        // fpm for the FPA at this GS
+      const desiredAltNow = tgt + cum * 6076.12 * tan;         // path altitude at present position
+      const vDev = alt - desiredAltNow;                        // + = above path
+      const descentNm = (alt - tgt) / (6076.12 * tan);         // distance the descent itself takes
+      const todNm = cum - descentNm;                           // distance ahead until TOD
+      const todSec = todNm > 0 ? (todNm / gs) * 3600 : 0;
+      return { wptId: wps[i].id, tgtAlt: tgt, dist: cum, vsReq, vsTgt, vDev, fpa: VNAV_FPA, todSec };
     }
   }
   return null;