diff --git a/scripts/format-scope.json b/scripts/format-scope.json
index 4a94003aa..de886bb04 100644
--- a/scripts/format-scope.json
+++ b/scripts/format-scope.json
@@ -1101,5 +1101,11 @@
   "src/app/layers/renderers.js",
   "src/app/layers/renderers.test.mjs",
   "src/data/lifecycleEngine.test.mjs",
-  "src/ui/shareRestorationEngine.test.mjs"
+  "src/ui/shareRestorationEngine.test.mjs",
+  "src/app/qaProbe.js",
+  "src/app/qaProbe.test.mjs",
+  "src/app/layers/qaSources.js",
+  "src/app/layers/qaSources.test.mjs",
+  "scripts/qa-w1-layers.mjs",
+  "src/bench/w1Feeds.js"
 ]
diff --git a/scripts/qa-label-readability.mjs b/scripts/qa-label-readability.mjs
index b7d17752c..f3f8219d6 100644
--- a/scripts/qa-label-readability.mjs
+++ b/scripts/qa-label-readability.mjs
@@ -4,7 +4,11 @@
  * legibility over bright ground.
  *
  * Run:
- *   node scripts/qa-label-readability.mjs --url http://localhost:4244 --tag after
+ *   node scripts/qa-label-readability.mjs --url http://localhost:4244 --tag after [--engine=cesium|navara]
+ *
+ * Engine-neutral: camera, tiles and layers go through the globe engine and the
+ * QA probe; an engine without the flights/satellites layers (Navara today)
+ * shoots the scenes without a contact field and says so.
  *
  * Every scene pins its own camera pose AND substitutes a deterministic
  * synthetic contact field for the live pollers, so a `before` run and an
@@ -36,7 +40,12 @@ const getOpt = (name, fallback) => {
   return index >= 0 && argv[index + 1] ? argv[index + 1] : fallback;
 };
 
-const APP_URL = getOpt('--url', 'http://localhost:4244');
+const ENGINE = argv.find((value) => value.startsWith('--engine='))?.slice(9) ?? 'cesium';
+const APP_URL = (() => {
+  const url = new URL(getOpt('--url', 'http://localhost:4244'));
+  url.searchParams.set('engine', ENGINE);
+  return url.href;
+})();
 const TAG = getOpt('--tag', 'after');
 /** Comma-separated scene-id prefixes. Empty runs the whole set. */
 const SCENE_FILTER = getOpt('--scenes', '')
@@ -205,11 +214,8 @@ async function settle(page) {
   while (Date.now() - started < SETTLE_MAX_MS) {
     await new Promise((resolve) => setTimeout(resolve, 1500));
     const state = await page.evaluate(() => {
-      const { viewer, tileset } = window.__godsEyeView;
-      return {
-        tilesLoaded: tileset?.tilesLoaded !== false,
-        pending: viewer.scene.globe?._surface?._tileLoadQueueHigh?.length ?? 0,
-      };
+      const { engine } = window.__godsEyeView;
+      return { tilesLoaded: engine.surface.tilesLoaded(), pending: 0 };
     });
     const settled = state.tilesLoaded && state.pending === 0;
     if (settled && previous && Date.now() - started > SETTLE_MIN_MS) return true;
@@ -254,7 +260,7 @@ async function main() {
 
     await page.goto(APP_URL, { waitUntil: 'domcontentloaded', timeout: 60_000 });
     await page.waitForFunction(
-      () => window.__godsEyeView?.viewer && window.__godsEyeView?.styleManager,
+      () => window.__godsEyeView?.layers && window.__godsEyeView?.styleManager,
       { timeout: 60_000, polling: 100 },
     );
     // flyToAustin arrives ~500 ms after init; let it start and land before any
@@ -268,12 +274,16 @@ async function main() {
 
     for (const scene of selected) {
       process.stdout.write(`  ${scene.id} … `);
-      await page.evaluate((spec) => {
-        const { viewer, dataManager, styleManager } = window.__godsEyeView;
-        viewer.camera.cancelFlight();
-        const Cartesian3 = viewer.camera.position.constructor;
+      const fieldShown = await page.evaluate(async (spec) => {
+        const { engine, dataManager, styleManager, layers } = window.__godsEyeView;
+        const geo = await import('/src/geo/index.js');
+        engine.camera.cancelFlight();
+        const Cartesian3 = Object.assign(
+          (x, y, z) => geo.cartesian3.create(x, y, z),
+          { fromDegrees: (lon, lat, height) => geo.cartesian3.fromDegrees(lon, lat, height) },
+        );
 
-        viewer.camera.setView({
+        engine.camera.setView({
           destination: Cartesian3.fromDegrees(
             spec.camera.lon, spec.camera.lat, spec.camera.height,
           ),
@@ -290,10 +300,9 @@ async function main() {
         // the frame comes back with two labels instead of a field. Building
         // straight off the camera basis guarantees every contact lands inside
         // the keyhole, at a known depth, in both the before and after runs.
-        const camera = viewer.camera;
-        const frustum = camera.frustum;
-        const halfHeight = Math.tan((frustum.fovy ?? frustum.fov ?? 1.0) / 2);
-        const halfWidth = halfHeight * (frustum.aspectRatio || 1.6);
+        const camera = engine.camera.pose();
+        const halfHeight = Math.tan((camera.fovy ?? 1.0) / 2);
+        const halfWidth = halfHeight * (camera.aspectRatio || 1.6);
         const basis = {
           px: camera.position.x, py: camera.position.y, pz: camera.position.z,
           dx: camera.direction.x, dy: camera.direction.y, dz: camera.direction.z,
@@ -305,7 +314,7 @@ async function main() {
         const pointAt = (ndcX, ndcY, distance) => {
           const sx = ndcX * halfWidth * distance;
           const sy = ndcY * halfHeight * distance;
-          return new Cartesian3(
+          return Cartesian3(
             basis.px + basis.dx * distance + basis.rx * sx + basis.ux * sy,
             basis.py + basis.dy * distance + basis.ry * sx + basis.uy * sy,
             basis.pz + basis.dz * distance + basis.rz * sx + basis.uz * sy,
@@ -347,6 +356,9 @@ async function main() {
           ? { satellites: build('s'), flights: [], military: [] }
           : { flights: build('f'), military: [], satellites: [] };
         window.__LABEL_EVIDENCE = assignment;
+        const fieldLayers = Object.keys(assignment).filter(
+          (layerId) => assignment[layerId].length,
+        );
         for (const layerId of Object.keys(assignment)) {
           const entry = dataManager.layers.get(layerId);
           if (entry?.module) {
@@ -362,6 +374,7 @@ async function main() {
           densityPct: 100,
           allocationStrategy: 'elastic',
         });
+        return fieldLayers.every((layerId) => layers.available(layerId));
       }, scene);
 
       const converged = await settle(page);
@@ -399,10 +412,11 @@ async function main() {
       const diagnostics = await page.evaluate(
         () => window.__godsEyeView.styleManager.getDetectionState?.() || {},
       );
-      results.push({ scene: scene.id, converged, ...stats });
+      results.push({ scene: scene.id, engine: ENGINE, converged, fieldShown, ...stats });
       console.log(
         `p05=${stats.p05} p25=${stats.p25} p50=${stats.p50} p95=${stats.p95}`
         + `${converged ? '' : '  (tiles did not fully settle)'}`
+        + `${fieldShown ? '' : `  (no contact field: its layers are not on ${ENGINE})`}`
         + `  [${diagnostics.detectionMode || '?'}]`,
       );
     }
diff --git a/scripts/qa-labels.mjs b/scripts/qa-labels.mjs
index 8d26dcb30..a631b598b 100644
--- a/scripts/qa-labels.mjs
+++ b/scripts/qa-labels.mjs
@@ -3,7 +3,12 @@
  * Deterministic QA for the detection overlay's bounded two-lane label pipeline.
  *
  * Run:
- *   node scripts/qa-labels.mjs --url http://localhost:4173
+ *   node scripts/qa-labels.mjs --url http://localhost:4173 [--engine=cesium|navara]
+ *
+ * Engine-neutral: the camera and frames go through the globe engine and the
+ * layers through the QA probe (window.__godsEyeView.layers). On an engine
+ * without the flights, military and satellites layers (Navara today) the
+ * field checks are SKIPPED and the settings checks still run.
  *
  * The harness replaces only the three detection read APIs in the loaded page.
  * It does not enable their network pollers or mutate repository data. The field
@@ -22,7 +27,12 @@ const getOpt = (name, fallback) => {
   return index >= 0 && argv[index + 1] ? argv[index + 1] : fallback;
 };
 
-const APP_URL = getOpt('--url', 'http://localhost:4173');
+const ENGINE = argv.find((value) => value.startsWith('--engine='))?.slice(9) ?? 'cesium';
+const APP_URL = (() => {
+  const url = new URL(getOpt('--url', 'http://localhost:4173'));
+  url.searchParams.set('engine', ENGINE);
+  return url.href;
+})();
 const APP_ORIGIN = new URL(APP_URL).origin;
 const HEADFUL = getFlag('--headful');
 const SHOT_DIR = path.resolve('qa-shots/labels');
@@ -74,6 +84,8 @@ function findChromeExecutable() {
 }
 
 const results = [];
+let skippedChecks = 0;
+let skippedField = false;
 function record(name, ok, detail) {
   results.push({ name, ok, detail });
   const tag = ok ? '\x1b[32mPASS\x1b[0m' : '\x1b[31mFAIL\x1b[0m';
@@ -271,7 +283,7 @@ async function main() {
 
     await page.goto(APP_URL, { waitUntil: 'domcontentloaded', timeout: 60000 });
     await page.waitForFunction(
-      () => window.__godsEyeView?.viewer && window.__godsEyeView?.styleManager,
+      () => window.__godsEyeView?.layers && window.__godsEyeView?.styleManager,
       { timeout: 60000, polling: 100 },
     );
 
@@ -279,7 +291,7 @@ async function main() {
     // Let that callback start, then cancel it before establishing the global
     // measurement camera so startup motion cannot invalidate the sample.
     await new Promise((resolve) => setTimeout(resolve, 600));
-    await page.evaluate(() => window.__godsEyeView.viewer.camera.cancelFlight());
+    await page.evaluate(() => window.__godsEyeView.engine.camera.cancelFlight());
 
     const stateChecks = await page.evaluate((storageKey) => {
       const manager = window.__godsEyeView.styleManager;
@@ -305,10 +317,32 @@ async function main() {
       `OFF=${stateChecks.off.densityPct}%, restore=${stateChecks.restoredFromOff.detectionMode}/${stateChecks.restoredFromOff.densityPct}%`,
     );
 
-    const injected = await page.evaluate(({ fieldCounts, normalCounts }) => {
-      const { viewer, dataManager, styleManager } = window.__godsEyeView;
-      viewer.camera.cancelFlight();
-      const Cartesian3 = viewer.camera.position.constructor;
+    const fieldLayers = ['flights', 'military', 'satellites'];
+    const missingLayers = await page.evaluate(
+      (ids) => ids.filter((id) => !window.__godsEyeView.layers.available(id)),
+      fieldLayers,
+    );
+    if (missingLayers.length) {
+      console.log(`  [SKIP] the deterministic field checks — no ${missingLayers.join(', ')} on ${ENGINE}`);
+      skippedChecks += 1;
+      record(
+        'console remains clean',
+        consoleErrors.length === 0,
+        consoleErrors.slice(0, 3).join(' | ') || '0 errors',
+      );
+      skippedField = true;
+      return;
+    }
+    const injected = await page.evaluate(async ({ fieldCounts, normalCounts }) => {
+      const { engine, dataManager, styleManager } = window.__godsEyeView;
+      const geo = await import('/src/geo/index.js');
+      engine.camera.cancelFlight();
+      // A frame counter on the engine (the samples are one per drawn frame).
+      window.__LABEL_QA_FRAME = 0;
+      engine.frames.postRender.addEventListener(() => {
+        window.__LABEL_QA_FRAME += 1;
+      });
+      const Cartesian3 = { fromDegrees: (lon, lat, height) => geo.cartesian3.fromDegrees(lon, lat, height) };
       const field = { flights: [], military: [], satellites: [] };
       const layerIds = Object.keys(field);
       const goldenAngle = Math.PI * (3 - Math.sqrt(5));
@@ -339,10 +373,15 @@ async function main() {
         entry.module.getDetectableObjects = () => window.__LABEL_QA_FIELD[layerId];
       }
 
-      viewer.camera.setView({
-        destination: Cartesian3.fromDegrees(-97, 30, 25000000),
-        orientation: { heading: 0, pitch: -Math.PI / 2, roll: 0 },
-      });
+      // The global camera, orbiting west to east (the old rotateRight about
+      // the globe centre at 25 000 km).
+      let orbitLon = -97;
+      const placeCamera = () =>
+        engine.camera.setView({
+          destination: Cartesian3.fromDegrees(orbitLon, 30, 25000000),
+          orientation: { heading: 0, pitch: -Math.PI / 2, roll: 0 },
+        });
+      placeCamera();
       styleManager.setDetection({
         enabled: true,
         densityPct: 100,
@@ -359,13 +398,14 @@ async function main() {
       let lastOrbitAt = performance.now();
       window.__LABEL_QA_ORBIT = setInterval(() => {
         const now = performance.now();
-        viewer.camera.rotateRight((now - lastOrbitAt) * 0.0000012);
+        orbitLon -= ((now - lastOrbitAt) * 0.0000012 * 180) / Math.PI;
         lastOrbitAt = now;
-        viewer.scene.requestRender();
+        placeCamera();
+        engine.render.request('qa-labels');
       }, 100);
       const sample = () => {
         const diagnostics = styleManager.getDetectionDiagnostics();
-        const frameNumber = viewer.scene.frameState?.frameNumber ?? -1;
+        const frameNumber = window.__LABEL_QA_FRAME;
         if (diagnostics && frameNumber !== window.__LABEL_QA.lastFrameNumber) {
           window.__LABEL_QA.lastFrameNumber = frameNumber;
           window.__LABEL_QA.frames.push({
@@ -395,7 +435,7 @@ async function main() {
             observationCount: Number(dataset.observationCount),
             selectedCount: Number(dataset.selectedCount),
             fadingCount: Number(dataset.fadingCount),
-            cameraHeight: viewer.camera.positionCartographic.height,
+            cameraHeight: engine.camera.height(),
             demandByLayer: JSON.parse(dataset.demandByLayer || '{}'),
             cohortByLayer: JSON.parse(dataset.cohortByLayer || '{}'),
             entitlementByLayer: JSON.parse(dataset.entitlementByLayer || '{}'),
@@ -420,12 +460,11 @@ async function main() {
     // -samples gates supersede it — same fix, deterministic instead of timed.)
     await waitForSettledSyntheticField(page);
     await page.evaluate(() => {
-      const viewer = window.__godsEyeView.viewer;
       const revision = Number(document.querySelector('#world-overlay-canvas')?.dataset?.solveRevision || 0);
       window.__LABEL_QA.solve = [];
       window.__LABEL_QA.frames = [];
       window.__LABEL_QA.lastRevision = revision;
-      window.__LABEL_QA.lastFrameNumber = viewer.scene.frameState?.frameNumber ?? -1;
+      window.__LABEL_QA.lastFrameNumber = window.__LABEL_QA_FRAME;
       window.__LABEL_QA.startedAt = performance.now();
     });
     const syntheticSampling = await waitForConclusiveSamples(page, {
@@ -460,12 +499,11 @@ async function main() {
       { timeout: SAMPLE_TIMEOUT_MS, polling: 100 },
     );
     await page.evaluate(() => {
-      const viewer = window.__godsEyeView.viewer;
       const revision = Number(document.querySelector('#world-overlay-canvas')?.dataset?.solveRevision || 0);
       window.__LABEL_QA.solve = [];
       window.__LABEL_QA.frames = [];
       window.__LABEL_QA.lastRevision = revision;
-      window.__LABEL_QA.lastFrameNumber = viewer.scene.frameState?.frameNumber ?? -1;
+      window.__LABEL_QA.lastFrameNumber = window.__LABEL_QA_FRAME;
       window.__LABEL_QA.startedAt = performance.now();
     });
     const normalSampling = await waitForConclusiveSamples(page, {
@@ -587,10 +625,15 @@ async function main() {
     console.log(`  Synthetic solves: ${solveSamples.length}; normal frames: ${normalFieldFrames.length} (${normalFrames.length} non-solve)`);
   } finally {
     await browser.close();
+    if (skippedField) summarize();
   }
 
+  summarize();
+}
+
+function summarize() {
   const failures = results.filter((result) => !result.ok);
-  console.log(`\n${results.length - failures.length}/${results.length} checks passed.`);
+  console.log(`\n${results.length - failures.length}/${results.length} checks passed${skippedChecks ? `, ${skippedChecks} skipped` : ''} (engine ${ENGINE}).`);
   if (failures.length) process.exit(1);
 }
 
diff --git a/scripts/qa-overlay-baseline.mjs b/scripts/qa-overlay-baseline.mjs
index 57dc1fcd7..72682c089 100644
--- a/scripts/qa-overlay-baseline.mjs
+++ b/scripts/qa-overlay-baseline.mjs
@@ -15,6 +15,12 @@
  *   node scripts/qa-overlay-baseline.mjs --screenshots-dir /tmp/overlay-shots
  *   node scripts/qa-overlay-baseline.mjs --hardware-gpu --headful
  *   node scripts/qa-overlay-baseline.mjs --dist-dir /tmp/gev-dist
+ *   node scripts/qa-overlay-baseline.mjs --engine=navara
+ *
+ * Engine-neutral: the camera and frames go through the globe engine and the
+ * layers through the QA probe (window.__godsEyeView.layers). A scene whose
+ * layers the engine does not have is SKIPPED; without a Cesium viewer the
+ * entity inventory reports the engine's mover sets instead.
  */
 
 import fs from 'node:fs';
@@ -263,7 +269,10 @@ function printScene(result) {
   }
   if (result.entityInventory) {
     const totals = result.entityInventory.totals;
-    console.log(`  scene total : entities ${totals.entities} · LabelGraphics ${totals.labelGraphics} (${totals.shownLabelGraphics} show=true) · primitive labels ${totals.primitiveLabels}`);
+    if (totals.entities === undefined)
+      console.log(`  scene total : mover sets ${totals.moverSets} · instances ${totals.moverInstances}`);
+    else
+      console.log(`  scene total : entities ${totals.entities} · LabelGraphics ${totals.labelGraphics} (${totals.shownLabelGraphics} show=true) · primitive labels ${totals.primitiveLabels}`);
   }
   for (const phaseName of ['motion', 'rest']) {
     const phase = result.samples?.[phaseName];
@@ -345,33 +354,29 @@ async function installPageInstrumentation(page) {
 async function waitForApp(page) {
   await page.goto(APP_URL, { waitUntil: 'domcontentloaded', timeout: 60_000 });
   await page.waitForFunction(
-    () => Boolean(window.__godsEyeView?.viewer && window.__godsEyeView?.dataManager),
+    () => Boolean(window.__godsEyeView?.layers && window.__godsEyeView?.dataManager),
     { timeout: 60_000 },
   );
   await page.evaluate(() => {
-    const viewer = window.__godsEyeView.viewer;
-    try { viewer.camera.cancelFlight(); } catch { /* no flight */ }
-    try { viewer.scene.tweens?.removeAll?.(); } catch { /* no tween collection */ }
+    const { engine, viewer } = window.__godsEyeView;
+    try { engine.camera.cancelFlight(); } catch { /* no flight */ }
+    try { viewer?.scene.tweens?.removeAll?.(); } catch { /* no tween collection */ }
   });
   await sleep(1_250);
 }
 
 async function setCamera(page, camera) {
   if (!camera) return;
-  await page.evaluate(([lon, lat, height, heading, pitch]) => {
-    const viewer = window.__godsEyeView.viewer;
-    const ellipsoid = viewer.scene.globe.ellipsoid;
-    viewer.camera.cancelFlight?.();
-    viewer.scene.tweens?.removeAll?.();
-    viewer.camera.setView({
-      destination: ellipsoid.cartographicToCartesian({
-        longitude: lon * Math.PI / 180,
-        latitude: lat * Math.PI / 180,
-        height,
-      }),
+  await page.evaluate(async ([lon, lat, height, heading, pitch]) => {
+    const { engine, viewer } = window.__godsEyeView;
+    const geo = await import('/src/geo/index.js');
+    engine.camera.cancelFlight();
+    viewer?.scene.tweens?.removeAll?.();
+    engine.camera.setView({
+      destination: geo.cartesian3.fromDegrees(lon, lat, height),
       orientation: { heading, pitch, roll: 0 },
     });
-    viewer.scene.requestRender?.();
+    engine.render.request('qa-overlay-baseline');
   }, camera);
 }
 
@@ -411,7 +416,19 @@ async function waitForLayer(page, layerId) {
 
 async function readEntityInventory(page) {
   return page.evaluate(() => {
-    const viewer = window.__godsEyeView.viewer;
+    const { viewer, layers } = window.__godsEyeView;
+    // Without a Cesium viewer (Navara): the engine's mover sets.
+    if (!viewer) {
+      const sets = layers.movers();
+      return {
+        totals: {
+          moverSets: sets.length,
+          moverInstances: sets.reduce((sum, set) => sum + set.count, 0),
+        },
+        collections: sets,
+        primitiveTypes: {},
+      };
+    }
     const time = viewer.clock.currentTime;
     const collections = [];
     const totals = {
@@ -605,7 +622,7 @@ async function prepareTrackedFlight(page, cockpit) {
   });
   if (!tracked.ok) return `Civil tracking unavailable (${tracked.reason})`;
   try {
-    await page.waitForFunction(() => Boolean(window.__godsEyeView.viewer.trackedEntity?.position), { timeout: 10_000 });
+    await page.waitForFunction(() => Boolean(window.__godsEyeView.layers.following()), { timeout: 10_000 });
   } catch {
     return 'Civil tracking did not create a tracked entity';
   }
@@ -638,7 +655,7 @@ async function prepareMission(page) {
   });
   if (!selected) return 'Mission roster did not expose a selectable mission';
   try {
-    await page.waitForFunction(() => String(window.__godsEyeView.viewer.selectedEntity?.id || '').startsWith('rocket-launch:'), { timeout: 10_000 });
+    await page.waitForFunction(() => String(window.__godsEyeView.viewer?.selectedEntity?.id || '').startsWith('rocket-launch:'), { timeout: 10_000 });
   } catch {
     return 'Mission selection did not reach the Cesium selected entity';
   }
@@ -647,6 +664,12 @@ async function prepareMission(page) {
 }
 
 async function prepareScene(page, scene) {
+  const missing = await page.evaluate(
+    (ids) => ids.filter((id) => !window.__godsEyeView.layers.available(id)),
+    scene.layers,
+  );
+  if (missing.length)
+    return { layerActivations: [], skipReason: `no ${missing.join(', ')} on ${ENGINE}` };
   if (scene.camera) await setCamera(page, scene.camera);
   const layerActivations = await activateLayers(page, scene.layers);
   let skipReason = null;
@@ -678,7 +701,28 @@ async function readCanvasSummary(page) {
 
 async function samplePhase(page, moving) {
   const raw = await page.evaluate(async ({ durationMs, movingCamera }) => {
-    const viewer = window.__godsEyeView.viewer;
+    const { engine } = window.__godsEyeView;
+    // Cesium's rotateRight / rotateUp: the camera turned about the axis
+    // through the globe centre along its up (right) vector.
+    const rotate = (axis, angle) => {
+      const pose = engine.camera.pose();
+      const len = Math.hypot(axis.x, axis.y, axis.z);
+      const [ux, uy, uz] = [axis.x / len, axis.y / len, axis.z / len];
+      const cos = Math.cos(angle);
+      const sin = Math.sin(angle);
+      const turn = (v) => {
+        const dot = ux * v.x + uy * v.y + uz * v.z;
+        return {
+          x: v.x * cos + (uy * v.z - uz * v.y) * sin + ux * dot * (1 - cos),
+          y: v.y * cos + (uz * v.x - ux * v.z) * sin + uy * dot * (1 - cos),
+          z: v.z * cos + (ux * v.y - uy * v.x) * sin + uz * dot * (1 - cos),
+        };
+      };
+      engine.camera.setView({
+        destination: turn(pose.position),
+        orientation: { direction: turn(pose.direction), up: turn(pose.up) },
+      });
+    };
     const instrumentation = window.__overlayBaselineInstrumentation;
     instrumentation?.reset?.();
     const intervals = [];
@@ -690,10 +734,11 @@ async function samplePhase(page, moving) {
         lastFrameAt = now;
         const elapsed = now - startedAt;
         if (movingCamera) {
-          viewer.camera.rotateRight(0.00035);
-          viewer.camera.rotateUp(0.00008 * Math.sin(elapsed / 600));
+          const pose = engine.camera.pose();
+          rotate(pose.up, -0.00035);
+          rotate(engine.camera.pose().right, 0.00008 * Math.sin(elapsed / 600));
         }
-        viewer.scene.requestRender?.();
+        engine.render.request('qa-overlay-baseline');
         if (elapsed >= durationMs) resolve();
         else requestAnimationFrame(step);
       };
@@ -813,7 +858,12 @@ async function runScene(browser, scene, shotsDir) {
   }
 }
 
-const APP_URL = getOpt('--url', DEFAULT_URL);
+const ENGINE = process.argv.find((value) => value.startsWith('--engine='))?.slice(9) ?? 'cesium';
+const APP_URL = (() => {
+  const url = new URL(getOpt('--url', DEFAULT_URL));
+  url.searchParams.set('engine', ENGINE);
+  return url.href;
+})();
 const DPR = Number(getOpt('--dpr', '1'));
 const JSON_PATH = getOpt('--json');
 const SCREENSHOTS_DIR = getOpt('--screenshots-dir');
diff --git a/scripts/qa-perf.mjs b/scripts/qa-perf.mjs
index 6aa5f9e89..86b40ba40 100644
--- a/scripts/qa-perf.mjs
+++ b/scripts/qa-perf.mjs
@@ -68,21 +68,35 @@
  * "world-overlay honours occluder churn as paint work" in
  * the project roadmap.
  *
- * Usage: node scripts/qa-perf.mjs [--url http://localhost:4173]
+ * Usage: node scripts/qa-perf.mjs [--url http://localhost:4173] [--engine=cesium|navara]
+ * Engine-neutral: the camera, frames and layers go through the globe engine
+ * and the QA probe (window.__godsEyeView.layers); on an engine without a
+ * layer (Navara today) that layer's checks are SKIPPED, not failed.
  * Requires a running dev server. Headless; flags disable occlusion
  * throttling so rAF cadence is trustworthy (hidden-pane gotcha).
  */
 import puppeteer from 'puppeteer';
 
 const argv = process.argv;
-const url = argv.includes('--url') ? argv[argv.indexOf('--url') + 1] : 'http://localhost:4173';
+const baseUrl = argv.includes('--url') ? argv[argv.indexOf('--url') + 1] : 'http://localhost:4173';
+const engineKind = argv.find((value) => value.startsWith('--engine='))?.slice(9) ?? 'cesium';
+const url = (() => {
+  const parsed = new URL(baseUrl);
+  parsed.searchParams.set('engine', engineKind);
+  return parsed.href;
+})();
 
 const results = [];
+let skipped = 0;
 function check(name, pass, detail) {
   results.push({ name, pass });
   const tag = pass ? 'PASS' : 'FAIL';
   console.log(`  [${tag}] ${name}${detail ? ` — ${JSON.stringify(detail)}` : ''}`);
 }
+function skip(name, reason) {
+  skipped += 1;
+  console.log(`  [SKIP] ${name} — ${reason}`);
+}
 
 const browser = await puppeteer.launch({
   headless: 'new',
@@ -103,20 +117,18 @@ try {
   const page = await browser.newPage();
   await page.setViewport({ width: 1440, height: 860 });
   await page.goto(url, { waitUntil: 'domcontentloaded' });
-  await page.waitForFunction(() => !!window.__godsEyeView?.viewer, { timeout: 90_000 });
+  await page.waitForFunction(() => !!window.__godsEyeView?.layers, { timeout: 90_000 });
+  const layerAvailable = (id) => page.evaluate((layerId) => window.__godsEyeView.layers.available(layerId), id);
   // Boot flyTo + tile warm + all deferred init.
   await new Promise((r) => setTimeout(r, 15_000));
 
   // Park deterministically and disable every layer.
   await page.evaluate(async () => {
     const gev = window.__godsEyeView;
-    const v = gev.viewer;
-    v.camera.cancelFlight();
-    const ell = v.scene.globe.ellipsoid;
-    v.camera.setView({
-      destination: ell.cartographicToCartesian({
-        longitude: -97.74 * Math.PI / 180, latitude: 30.27 * Math.PI / 180, height: 60_000,
-      }),
+    const geo = await import('/src/geo/index.js');
+    gev.engine.camera.cancelFlight();
+    gev.engine.camera.setView({
+      destination: geo.cartesian3.fromDegrees(-97.74, 30.27, 60_000),
       orientation: { heading: 0, pitch: -Math.PI / 2, roll: 0 },
     });
     for (const [id, entry] of gev.dataManager.layers) {
@@ -128,9 +140,9 @@ try {
 
   /** Count scene postRender fires and rAF ticks over windowMs. */
   const countFrames = (windowMs) => page.evaluate((ms) => new Promise((resolve) => {
-    const scene = window.__godsEyeView.viewer.scene;
+    const { frames } = window.__godsEyeView.engine;
     let renders = 0; let rafs = 0;
-    const remove = scene.postRender.addEventListener(() => { renders += 1; });
+    const remove = frames.postRender.addEventListener(() => { renders += 1; });
     const t0 = performance.now();
     const tick = () => {
       rafs += 1;
@@ -255,10 +267,10 @@ try {
   const detectMove = await Promise.all([
     countFrames(2_500),
     page.evaluate(() => new Promise((resolve) => {
-      const v = window.__godsEyeView.viewer;
+      const { camera } = window.__godsEyeView.engine;
       let steps = 0;
       const id = setInterval(() => {
-        v.camera.moveForward(50);
+        camera.zoomIn(50);
         steps += 1;
         if (steps >= 20) { clearInterval(id); resolve(true); }
       }, 60);
@@ -281,13 +293,13 @@ try {
     // identity is one painted frame. Sampling it per scene frame is enough to
     // tell "painting" from "silent" without reaching into module internals.
     let last = gev.styleManager.getDetectionDiagnostics?.();
-    const remove = gev.viewer.scene.postRender.addEventListener(() => {
+    const remove = gev.engine.frames.postRender.addEventListener(() => {
       const now = gev.styleManager.getDetectionDiagnostics?.();
       if (now && now !== last) { paints += 1; last = now; }
     });
     let steps = 0;
     const id = setInterval(() => {
-      gev.viewer.camera.moveForward(50);
+      gev.engine.camera.zoomIn(50);
       steps += 1;
       if (steps >= 20) {
         clearInterval(id);
@@ -325,9 +337,15 @@ try {
   await page.evaluate(() => { window.__godsEyeView.styleManager.setStyle('retro'); });
   await new Promise((r) => setTimeout(r, 900)); // crossfade + first ticks
   const dAnim = await diag();
-  check('animated style takes the style-anim hold (continuous)', dAnim?.mode === 'continuous' && dAnim.holds.includes('style-anim'), dAnim);
-  const animFrames = await countFrames(2_000);
-  check('animated style keeps frames flowing (≥50% rAF)', animFrames.renders >= animFrames.rafs * 0.5, animFrames);
+  // The animated styles are Cesium post-process stages; Navara draws its own
+  // looks and has no style animation (a known gap, not a regression).
+  if (engineKind === 'cesium') {
+    check('animated style takes the style-anim hold (continuous)', dAnim?.mode === 'continuous' && dAnim.holds.includes('style-anim'), dAnim);
+    const animFrames = await countFrames(2_000);
+    check('animated style keeps frames flowing (≥50% rAF)', animFrames.renders >= animFrames.rafs * 0.5, animFrames);
+  } else {
+    skip('animated style takes the style-anim hold and keeps frames flowing', `the visual styles are Cesium post stages; ${engineKind} has none`);
+  }
   // Returning to normal keeps detection ON by design (it is the default, and
   // detection persists across style switches). Since 2026-08-22 detection holds
   // nothing, so this asserts the strictly harder thing: the scene returns to
@@ -349,26 +367,26 @@ try {
   );
 
   // ── 2c. satellites holder enters and leaves diagnostics ───────────────
-  await page.evaluate(async () => {
-    await window.__godsEyeView.dataManager.setEnabled('satellites', true, { origin: 'user' });
-  });
-  const dSat = await diag();
-  check('satellites enable registers its holder', dSat?.holds.includes('satellites'), dSat);
-  await page.evaluate(async () => {
-    await window.__godsEyeView.dataManager.setEnabled('satellites', false, { origin: 'user' });
-  });
-  await new Promise((r) => setTimeout(r, 2_000));
-  const dSatOff = await diag();
-  check('satellites disable releases its holder', !dSatOff?.holds.includes('satellites'), dSatOff);
+  if (await layerAvailable('satellites')) {
+    await page.evaluate(() => window.__godsEyeView.layers.enable('satellites'));
+    const dSat = await diag();
+    check('satellites enable registers its holder', dSat?.holds.includes('satellites'), dSat);
+    await page.evaluate(() => window.__godsEyeView.layers.disable('satellites'));
+    await new Promise((r) => setTimeout(r, 2_000));
+    const dSatOff = await diag();
+    check('satellites disable releases its holder', !dSatOff?.holds.includes('satellites'), dSatOff);
+  } else {
+    skip('satellites holder enters and leaves diagnostics', `no satellites layer on ${engineKind}`);
+  }
 
   // ── 3. camera movement renders (Cesium-native path) ───────────────────
   const duringMove = await Promise.all([
     countFrames(2_500),
     page.evaluate(() => new Promise((resolve) => {
-      const v = window.__godsEyeView.viewer;
+      const { camera } = window.__godsEyeView.engine;
       let steps = 0;
       const id = setInterval(() => {
-        v.camera.moveForward(50);
+        camera.zoomIn(50);
         steps += 1;
         if (steps >= 20) { clearInterval(id); resolve(true); }
       }, 60);
@@ -378,36 +396,40 @@ try {
   await new Promise((r) => setTimeout(r, 3_000)); // settle
 
   // ── 4. flights enabled → continuous ───────────────────────────────────
-  await page.evaluate(async () => {
-    await window.__godsEyeView.dataManager.setEnabled('flights', true, { origin: 'user' });
-  });
-  await new Promise((r) => setTimeout(r, 5_000));
-  const active = await countFrames(5_000);
-  const d4 = await diag();
-  check('governor reports continuous mode with flights on', d4?.mode === 'continuous', d4);
-  check('flights-on cadence ≈ rAF cadence (≥70%)', active.renders >= active.rafs * 0.7, active);
-  check('flights-on renders ≥5× idle renders', active.renders >= Math.max(1, idle.renders) * 5, { active: active.renders, idle: idle.renders });
+  if (await layerAvailable('flights')) {
+    await page.evaluate(async () => {
+      await window.__godsEyeView.layers.enable('flights');
+    });
+    await new Promise((r) => setTimeout(r, 5_000));
+    const active = await countFrames(5_000);
+    const d4 = await diag();
+    check('governor reports continuous mode with flights on', d4?.mode === 'continuous', d4);
+    check('flights-on cadence ≈ rAF cadence (≥70%)', active.renders >= active.rafs * 0.7, active);
+    check('flights-on renders ≥5× idle renders', active.renders >= Math.max(1, idle.renders) * 5, { active: active.renders, idle: idle.renders });
 
-  // ── 5. flights disabled → idle again ──────────────────────────────────
-  await page.evaluate(async () => {
-    await window.__godsEyeView.dataManager.setEnabled('flights', false, { origin: 'user' });
-  });
-  // Deselect flows, fades, and the chrome churn the overlay host re-evaluates
-  // its occluders against all have to drain first — and this teardown, like the
-  // one in the setup above, marks the HUD summary dirty, so the same deferred
-  // typewriter is still ahead of us. Same rule: hold a quiet run longer than one
-  // refresh period before counting anything.
-  const teardownSettle = await settleUntilQuiet();
-  const idleAgain = await countFrames(5_000);
-  const d5 = await diag();
-  check('the scene holds a settled quiet run again before the second idle window', teardownSettle.quiet, teardownSettle);
-  check('governor returns to idle after disable', d5?.mode === 'idle', d5);
-  check('scene stops rendering again (≤4 fires / 5s)', idleAgain.renders <= 4, idleAgain);
+    // ── 5. flights disabled → idle again ──────────────────────────────────
+    await page.evaluate(async () => {
+      await window.__godsEyeView.layers.disable('flights');
+    });
+    // Deselect flows, fades, and the chrome churn the overlay host re-evaluates
+    // its occluders against all have to drain first — and this teardown, like the
+    // one in the setup above, marks the HUD summary dirty, so the same deferred
+    // typewriter is still ahead of us. Same rule: hold a quiet run longer than one
+    // refresh period before counting anything.
+    const teardownSettle = await settleUntilQuiet();
+    const idleAgain = await countFrames(5_000);
+    const d5 = await diag();
+    check('the scene holds a settled quiet run again before the second idle window', teardownSettle.quiet, teardownSettle);
+    check('governor returns to idle after disable', d5?.mode === 'idle', d5);
+    check('scene stops rendering again (≤4 fires / 5s)', idleAgain.renders <= 4, idleAgain);
+  } else {
+    skip('flights on → continuous, off → idle again', `no flights layer on ${engineKind}`);
+  }
 } finally {
   await browser.close();
 }
 
 const passed = results.filter((r) => r.pass).length;
 console.log(`\nqa-perf: ${passed}/${results.length} passed`);
-console.log(`RESULT: ${passed} passed, ${results.length - passed} failed, 0 skipped`);
+console.log(`RESULT: ${passed} passed, ${results.length - passed} failed, ${skipped} skipped (engine ${engineKind})`);
 process.exit(passed === results.length ? 0 : 1);
diff --git a/src/app/layers/qaSources.js b/src/app/layers/qaSources.js
new file mode 100644
index 000000000..f8f351062
--- /dev/null
+++ b/src/app/layers/qaSources.js
@@ -0,0 +1,71 @@
+// QA fixture sources (only with allowQaRegistration, i.e. the dev server):
+// `?qaFeed=flights:synthetic:10000,vessels:fixture` replaces those layers'
+// live sources with seeded synthetic answers (src/bench/w1Feeds.js) served
+// through the live sources' own parsers, so the layers see the same snapshot
+// shape. Times are relative to now, so the objects stay fresh.
+//
+//   flights:synthetic[:count]   OpenSky states, `count` aircraft (8 000)
+//   vessels:fixture             12 000 AIS rows, or those within an area
+
+import {
+  createFlightSource,
+  createVesselSource,
+} from '../../sources/live/standalone.js';
+import { syntheticFlights, syntheticVessels } from '../../bench/w1Feeds.js';
+
+const KINDS = Object.freeze({
+  flights: new Set(['synthetic']),
+  vessels: new Set(['fixture']),
+});
+
+/** The qaFeed entries of a location search, or a TypeError. */
+export function parseQaFeed(search = '') {
+  const value = new URLSearchParams(search).get('qaFeed');
+  if (!value) return [];
+  return value.split(',').map((item) => {
+    const [layer, kind, rawCount] = item.split(':');
+    const count = rawCount === undefined ? null : Number(rawCount);
+    if (
+      !KINDS[layer]?.has(kind) ||
+      (count !== null && !(Number.isInteger(count) && count > 0))
+    )
+      throw new TypeError(
+        `qaFeed: unknown entry "${item}" (flights:synthetic[:count], vessels:fixture)`,
+      );
+    return { layer, kind, count };
+  });
+}
+
+const json = (payload) =>
+  new Response(JSON.stringify(payload), {
+    status: 200,
+    headers: { 'content-type': 'application/json' },
+  });
+
+/** Source overrides for createStandaloneLayerSources. */
+export function createQaSources(entries, { now = () => Date.now() } = {}) {
+  const sources = {};
+  for (const { layer, count } of entries) {
+    if (layer === 'flights')
+      sources.flights = createFlightSource({
+        now,
+        fetchImpl: async () =>
+          json(syntheticFlights({ nowMs: now(), count: count ?? 8000 })),
+      });
+    if (layer === 'vessels')
+      sources.vessels = createVesselSource({
+        fetchImpl: async (url) => {
+          const params = new URL(url).searchParams;
+          const area = params.has('lat')
+            ? {
+                lat: Number(params.get('lat')),
+                lon: Number(params.get('lon')),
+                radiusKm: Number(params.get('radius_km')),
+              }
+            : null;
+          return json(syntheticVessels({ nowMs: now(), area }));
+        },
+      });
+  }
+  return sources;
+}
diff --git a/src/app/layers/qaSources.test.mjs b/src/app/layers/qaSources.test.mjs
new file mode 100644
index 000000000..0685be701
--- /dev/null
+++ b/src/app/layers/qaSources.test.mjs
@@ -0,0 +1,44 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { createQaSources, parseQaFeed } from './qaSources.js';
+
+test('qaFeed names fixture sources per layer', () => {
+  assert.deepEqual(
+    parseQaFeed('?qaFeed=flights:synthetic:10000,vessels:fixture'),
+    [
+      { layer: 'flights', kind: 'synthetic', count: 10000 },
+      { layer: 'vessels', kind: 'fixture', count: null },
+    ],
+  );
+  assert.deepEqual(parseQaFeed('?engine=navara'), []);
+  assert.throws(() => parseQaFeed('?qaFeed=flights:live'), /qaFeed/);
+  assert.throws(() => parseQaFeed('?qaFeed=weather:fixture'), /qaFeed/);
+  assert.throws(() => parseQaFeed('?qaFeed=flights:synthetic:-3'), /qaFeed/);
+});
+
+test('fixture sources answer with the live sources’ snapshot shape', async () => {
+  const now = Date.UTC(2026, 9, 16, 12);
+  const sources = createQaSources(
+    parseQaFeed('?qaFeed=flights:synthetic:500,vessels:fixture'),
+    { now: () => now },
+  );
+  const flights = await sources.flights.getSnapshot({});
+  assert.equal(flights.records.length, 500);
+  assert.ok(
+    flights.records.every((record) => Number.isFinite(record.latitude)),
+  );
+  // Seeded: the same aircraft every time.
+  const again = await sources.flights.getSnapshot({});
+  assert.deepEqual(
+    again.records.map(({ id }) => id),
+    flights.records.map(({ id }) => id),
+  );
+  const vessels = await sources.vessels.getSnapshot({ maxRows: 12000 });
+  assert.equal(vessels.records.length, 12000);
+  const near = await sources.vessels.getSnapshot({
+    maxRows: 12000,
+    area: { lat: 40.65724, lon: -73.78, radiusKm: 10 },
+  });
+  assert.ok(near.records.length > 10 && near.records.length < 12000);
+  assert.deepEqual(createQaSources([]), {});
+});
diff --git a/src/app/qaProbe.js b/src/app/qaProbe.js
new file mode 100644
index 000000000..9e7bc25a6
--- /dev/null
+++ b/src/app/qaProbe.js
@@ -0,0 +1,82 @@
+// The engine-neutral QA probe: window.__godsEyeView.layers. QA scripts ask
+// it what a layer shows and where, the same way on Cesium and Navara,
+// instead of reading Cesium objects. Read-only apart from enable/disable,
+// which go through the layer manager as a user toggle would.
+//
+//   list()                 [{ id, name, enabled, available }] (the catalog)
+//   unavailable()          [{ id, name }] layers this engine leaves out
+//   available(id)          whether this engine can show layer `id`
+//   enable(id) / disable(id)   → Promise<boolean>
+//   objects(id, max?)      [{ id, label, position, screen }] (position a
+//                          plain { x, y, z }, screen a window point or null)
+//   screenOf(id, objectId) the window point of one object, or null
+//   selected(id)           the layer's tracked/selected info, or null
+//   following()            { label, native } of engine.camera.following()
+//   movers()               engine.movers.list()
+//   framesDrawn()          frames drawn since the probe started
+
+const plain = (position) =>
+  position ? { x: position.x, y: position.y, z: position.z } : null;
+
+/**
+ * @param {{
+ *   engine: import('../globe/contract.js').GlobeEngine,
+ *   dataManager: object,
+ *   availability: import('./layers/renderers.js').LayerAvailability,
+ * }} options
+ */
+export function createQaProbe({ engine, dataManager, availability }) {
+  let frames = 0;
+  const removeFrames = engine.frames.postRender.addEventListener(() => {
+    frames++;
+  });
+  const moduleOf = (layerId) => dataManager.layers.get(layerId)?.module;
+  const screenOf = (position) => {
+    if (!position || !engine.projector.horizonVisible(position)) return null;
+    const screen = engine.projector.worldToWindow(position);
+    return screen ? { x: screen.x, y: screen.y } : null;
+  };
+  const objects = (layerId, max = 500) => {
+    const rows = moduleOf(layerId)?.getAllPositions?.(max) ?? [];
+    return rows.map((row) => ({
+      id: row.id,
+      label: row.label ?? null,
+      position: plain(row.position),
+      screen: screenOf(row.position),
+    }));
+  };
+  return {
+    list: () =>
+      dataManager.getAll().map(({ id, name, enabled }) => ({
+        id,
+        name,
+        enabled: Boolean(enabled),
+        available: availability.isAvailable(id),
+      })),
+    unavailable: () => availability.unavailable(),
+    available: (layerId) => availability.isAvailable(layerId),
+    enable: (layerId) =>
+      dataManager.setEnabled(layerId, true, { origin: 'user' }),
+    disable: (layerId) =>
+      dataManager.setEnabled(layerId, false, { origin: 'user' }),
+    objects,
+    screenOf(layerId, objectId) {
+      const row = (moduleOf(layerId)?.getAllPositions?.(1_000_000) ?? []).find(
+        ({ id }) => String(id) === String(objectId),
+      );
+      return row ? screenOf(row.position) : null;
+    },
+    selected: (layerId) => moduleOf(layerId)?.getTrackedInfo?.() ?? null,
+    following() {
+      const handle = engine.camera.following();
+      if (!handle) return null;
+      return {
+        label: handle.label?.id ?? null,
+        native: handle.native?.id ?? null,
+      };
+    },
+    movers: () => engine.movers.list(),
+    framesDrawn: () => frames,
+    destroy: () => removeFrames(),
+  };
+}
diff --git a/src/app/qaProbe.test.mjs b/src/app/qaProbe.test.mjs
new file mode 100644
index 000000000..a247f70e0
--- /dev/null
+++ b/src/app/qaProbe.test.mjs
@@ -0,0 +1,103 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import * as geo from '../geo/index.js';
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
+import { createQaProbe } from './qaProbe.js';
+import {
+  createLayerAvailability,
+  createRendererRegistry,
+} from './layers/renderers.js';
+
+function fakeManager(modules) {
+  const enabled = new Set();
+  return {
+    layers: new Map(modules.map((module) => [module.id, { module }])),
+    getAll: () =>
+      modules.map(({ id, name }) => ({ id, name, enabled: enabled.has(id) })),
+    isEnabled: (id) => enabled.has(id),
+    async setEnabled(id, value) {
+      if (value) enabled.add(id);
+      else enabled.delete(id);
+      return true;
+    },
+  };
+}
+
+test('the probe lists, toggles and reads layers through the engine', async () => {
+  const engine = createFakeEngine({ kind: 'navara' });
+  const position = geo.cartesian3.fromDegrees(-73.78, 40.64, 1000);
+  const flights = {
+    id: 'flights',
+    name: 'Live Flights',
+    getAllPositions: () => [{ id: 'ae01ce', label: 'UAL1', position }],
+    getTrackedInfo: () => ({ icao24: 'ae01ce' }),
+  };
+  const manager = fakeManager([flights]);
+  const registry = createRendererRegistry();
+  registry.register('navara', { flights: () => ({}) });
+  const probe = createQaProbe({
+    engine,
+    dataManager: manager,
+    availability: createLayerAvailability('navara', { registry }),
+  });
+  assert.deepEqual(probe.list(), [
+    { id: 'flights', name: 'Live Flights', enabled: false, available: true },
+  ]);
+  assert.equal(probe.available('flights'), true);
+  assert.equal(probe.available('satellites'), false);
+  assert.deepEqual(
+    probe
+      .unavailable()
+      .map(({ id }) => id)
+      .includes('satellites'),
+    true,
+  );
+  assert.equal(await probe.enable('flights'), true);
+  assert.equal(manager.isEnabled('flights'), true);
+  engine.camera.setView({
+    destination: geo.cartesian3.fromDegrees(-73.78, 40.64, 50_000),
+  });
+  engine.fake.script('worldToWindow', () => ({ x: 640, y: 400 }));
+  const [object] = probe.objects('flights');
+  assert.equal(object.id, 'ae01ce');
+  assert.deepEqual(
+    [object.position.x, object.position.y, object.position.z],
+    [position.x, position.y, position.z],
+  );
+  assert.deepEqual(object.screen, { x: 640, y: 400 });
+  assert.deepEqual(probe.screenOf('flights', 'ae01ce'), { x: 640, y: 400 });
+  assert.equal(probe.screenOf('flights', 'nope'), null);
+  assert.deepEqual(probe.selected('flights'), { icao24: 'ae01ce' });
+  assert.deepEqual(probe.objects('unknown'), []);
+  // Follow, movers and frames come from the engine.
+  assert.equal(probe.following(), null);
+  engine.camera.follow({
+    position: () => position,
+    viewFrom: { x: 0, y: -1000, z: 300 },
+    label: {
+      id: 'flights:ae01ce',
+      model: { title: 'UAL1' },
+      position: () => position,
+    },
+  });
+  assert.deepEqual(probe.following(), {
+    label: 'flights:ae01ce',
+    native: null,
+  });
+  engine.movers.createSet({
+    id: 'fleet',
+    kind: 'point',
+    capacity: 4,
+    point: { sizePx: 4 },
+  });
+  assert.deepEqual(probe.movers(), [
+    { id: 'fleet', kind: 'point', count: 0, capacity: 4 },
+  ]);
+  const before = probe.framesDrawn();
+  engine.fake.frame();
+  engine.fake.frame();
+  assert.equal(probe.framesDrawn() - before, 2);
+  assert.equal(await probe.disable('flights'), true);
+  assert.equal(manager.isEnabled('flights'), false);
+  probe.destroy();
+});
diff --git a/src/bench/w1Feeds.js b/src/bench/w1Feeds.js
new file mode 100644
index 000000000..03f4b2bfc
--- /dev/null
+++ b/src/bench/w1Feeds.js
@@ -0,0 +1,162 @@
+// Seeded synthetic feed answers: the global /api/flights snapshot (OpenSky
+// states), 12 000 AIS vessels on /api/vessels (with and without an area) and
+// the local receivers' 1090 MHz and 978 MHz UAT aircraft near JFK, timed
+// relative to one instant, so every run sees the same objects at the same
+// places. Pure: Node and browser, no I/O. Used by the W1 baseline recordings
+// (src/tooling/w1Feeds.js) and the app's QA fixture sources
+// (src/app/layers/qaSources.js).
+
+import { createSyntheticFlights } from './syntheticFlights.js';
+
+/** The replay clock of the synthetic recordings: 2026-10-16T12:00:00Z. */
+export const W1_FROZEN_MS = Date.UTC(2026, 9, 16, 12);
+const JFK = { lat: 40.64, lng: -73.78 };
+
+/** Small deterministic PRNG (as syntheticFlights). */
+function mulberry32(seed) {
+  let state = seed >>> 0;
+  return () => {
+    state = (state + 0x6d2b79f5) >>> 0;
+    let t = state;
+    t = Math.imul(t ^ (t >>> 15), t | 1);
+    t ^= t + Math.imul(t ^ (t >>> 7), t | 61);
+    return ((t ^ (t >>> 14)) >>> 0) / 4294967296;
+  };
+}
+
+const hex = (value, digits) => value.toString(16).padStart(digits, '0');
+
+/** An OpenSky states payload: `count` aircraft, 2 000 of them near JFK. */
+export function syntheticFlights({
+  nowMs = W1_FROZEN_MS,
+  count = 8_000,
+  seed = 11,
+} = {}) {
+  const fleet = createSyntheticFlights({
+    count,
+    seed,
+    near: { ...JFK, radiusM: 60_000, count: Math.min(2_000, count) },
+  });
+  const random = mulberry32(seed + 1);
+  const nowSec = Math.floor(nowMs / 1000);
+  const states = [];
+  for (let index = 0; index < count; index++) {
+    const age = Math.floor(random() * 10);
+    states.push([
+      hex(0xa00000 + index, 6),
+      `GEV${String(index).padStart(4, '0')}`,
+      'United States',
+      nowSec - age,
+      nowSec - Math.min(age, 2),
+      Number(fleet.lon[index].toFixed(5)),
+      Number(fleet.lat[index].toFixed(5)),
+      Math.round(fleet.alt[index]),
+      false,
+      Number(fleet.speed[index].toFixed(1)),
+      Number(fleet.heading[index].toFixed(1)),
+      0,
+      null,
+      Math.round(fleet.alt[index]) + 30,
+      null,
+      false,
+      0,
+      index % 7 === 0 ? 1 : 3,
+    ]);
+  }
+  return { time: nowSec, states };
+}
+
+const PORTS = [
+  { lat: 40.6, lon: -74.02, spread: 0.25 }, // New York harbour
+  { lat: 51.95, lon: 4.1, spread: 0.4 }, // Rotterdam
+  { lat: 29.7, lon: -95.0, spread: 0.3 }, // Houston
+  { lat: 1.26, lon: 103.8, spread: 0.4 }, // Singapore
+];
+
+function allVessels(nowMs, seed) {
+  const random = mulberry32(seed);
+  const nowSec = Math.floor(nowMs / 1000);
+  const rows = [];
+  for (let index = 0; index < 12_000; index++) {
+    const port = index < 4_000 ? PORTS[index % PORTS.length] : null;
+    const lat = port
+      ? port.lat + (random() - 0.5) * port.spread
+      : random() * 120 - 60;
+    const lon = port
+      ? port.lon + (random() - 0.5) * port.spread * 1.5
+      : random() * 360 - 180;
+    rows.push({
+      mmsi: String(200_000_000 + index),
+      lat: Number(lat.toFixed(5)),
+      lon: Number(lon.toFixed(5)),
+      name: `GEV VESSEL ${index}`,
+      imo: '',
+      type: ['Cargo', 'Tanker', 'Passenger', 'Fishing', 'Tug'][index % 5],
+      destination: '',
+      speed: Number((random() * 18).toFixed(1)),
+      course: Math.round(random() * 360),
+      heading: Math.round(random() * 360),
+      last_position_epoch: nowSec - Math.floor(random() * 120),
+    });
+  }
+  return rows;
+}
+
+const kmBetween = (a, b) => {
+  const toRad = Math.PI / 180;
+  const dLat = (b.lat - a.lat) * toRad;
+  const dLon = (b.lon - a.lon) * toRad;
+  const h =
+    Math.sin(dLat / 2) ** 2 +
+    Math.cos(a.lat * toRad) * Math.cos(b.lat * toRad) * Math.sin(dLon / 2) ** 2;
+  return 2 * 6371 * Math.asin(Math.sqrt(h));
+};
+
+/** The /api/vessels answer: 12 000 rows, or those within `area`. */
+export function syntheticVessels({
+  nowMs = W1_FROZEN_MS,
+  seed = 21,
+  area = null,
+} = {}) {
+  let rows = allVessels(nowMs, seed);
+  if (area) rows = rows.filter((row) => kmBetween(area, row) <= area.radiusKm);
+  return { rows, newestPositionAt: nowMs };
+}
+
+/** The /api/local-receivers/aircraft answer: 1090 MHz and 978 MHz UAT aircraft. */
+export function syntheticLocalReceivers({
+  nowMs = W1_FROZEN_MS,
+  seed = 31,
+} = {}) {
+  const random = mulberry32(seed);
+  const records = [];
+  for (let index = 0; index < 40; index++) {
+    const uat = index % 4 === 0;
+    records.push({
+      icao: hex(0xad0000 + index, 6),
+      callsign: `LCL${index}`,
+      lat: Number((JFK.lat + (random() - 0.5) * 0.8).toFixed(5)),
+      lon: Number((JFK.lng + (random() - 0.5) * 1.0).toFixed(5)),
+      altitudeFt: Math.round(1_000 + random() * 20_000),
+      groundSpeedKt: Math.round(80 + random() * 300),
+      trackDeg: Math.round(random() * 360),
+      verticalRateFpm: 0,
+      onGround: false,
+      category: uat ? 'A1' : 'A3',
+      lastPositionAt: nowMs - Math.floor(random() * 2_000),
+      lastMessageAt: nowMs - Math.floor(random() * 500),
+      messageCount: 50,
+      band: uat ? '978' : '1090',
+      source: 'feed',
+    });
+  }
+  return {
+    configured: true,
+    generatedAt: nowMs,
+    feeds: [
+      { band: '1090', label: '1090 MHz', status: 'live', aircraft: 30 },
+      { band: '978', label: '978 MHz UAT', status: 'live', aircraft: 10 },
+    ],
+    records,
+  };
+}
diff --git a/src/standalone/application.js b/src/standalone/application.js
index 40c5d4d04..bda125fa2 100644
--- a/src/standalone/application.js
+++ b/src/standalone/application.js
@@ -8,6 +8,7 @@ import { createStandaloneData } from './data.js';
 import { createStandaloneTools } from './tools.js';
 import { createGoogleTokenSource } from '../maps/googleTokens.js';
 import { resolveEngineKind } from '../app/engineChoice.js';
+import { createQaProbe } from '../app/qaProbe.js';
 
 // The existing controls and layer catalog contain page-scoped state.
 let constructed = false;
@@ -65,9 +66,18 @@ export function createStandaloneApplication({
       // The catalog of this engine: on Navara only the layers with a Navara
       // renderer (src/app/layers/renderers.js; none yet), the others' state
       // kept for links.
+      // QA fixture sources (?qaFeed=…) on the dev server only.
+      const search = globalThis.location?.search ?? '';
+      const qaSources =
+        allowQaRegistration && /[?&]qaFeed=/.test(search)
+          ? await import('../app/layers/qaSources.js').then(
+              ({ createQaSources, parseQaFeed }) =>
+                createQaSources(parseQaFeed(search)),
+            )
+          : {};
       catalog = createStandaloneCatalog({
         engineKind,
-        sources,
+        sources: { ...sources, ...qaSources },
         streetLevelProviders,
         nepalBoundaryResolver: (signal) =>
           scene.operations.annotationResolver.resolveRegionRingForQuery(
@@ -91,7 +101,28 @@ export function createStandaloneApplication({
       }),
     createData: (context) =>
       createStandaloneData({ ...context, allowQaRegistration, catalog }),
-    createTools: (context) =>
-      createStandaloneTools({ ...context, loadingScreen, placeSearch, voice }),
+    createTools: async (context) => {
+      const tools = await createStandaloneTools({
+        ...context,
+        loadingScreen,
+        placeSearch,
+        voice,
+      });
+      // The engine-neutral QA probe on the debug handle (src/app/qaProbe.js).
+      const debug = globalThis.window?.__godsEyeView;
+      if (debug) {
+        const probe = createQaProbe({
+          engine: context.scene.engine,
+          dataManager: context.data.dataManager,
+          availability: catalog.availability,
+        });
+        debug.layers = probe;
+        context.defer(() => {
+          probe.destroy();
+          if (debug.layers === probe) delete debug.layers;
+        });
+      }
+      return tools;
+    },
   });
 }