diff --git a/CHANGELOG.md b/CHANGELOG.md
index 419c03e45..8527900d4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Changelog
 
+- Aircraft track backfill (`/api/opensky-track`, `/api/adsblol/trace`) now
+  answers 502 when the upstream body exceeds the 5 MB cap, instead of a 200
+  whose error body the client read as an empty track. The failure is cached
+  like other upstream errors, so retries inside the 60 s window do not spend
+  OpenSky credits (Raushankumar0720, #720, #722).
+
 - Saving a key from Provider Settings works again on Macs where Nix or
   Homebrew coreutils sit ahead of `/bin` on `PATH`. The credential hardener
   now spawns Apple's `/bin/chmod -N` by absolute path; GNU `chmod` has no `-N`,
diff --git a/server/providers/aircraft/tracks.js b/server/providers/aircraft/tracks.js
index 7d9501628..2c7b78a78 100644
--- a/server/providers/aircraft/tracks.js
+++ b/server/providers/aircraft/tracks.js
@@ -45,7 +45,9 @@ export function trackBackfillProxies() {
       RESPONSE_CAP_BYTES,
     );
     let body;
+    let status = upstream.status;
     if (tooLarge) {
+      status = 502;
       body = JSON.stringify({ error: 'Upstream track response too large' });
     } else if (!upstream.ok) {
       // Sanitize upstream error surface; status code is signal enough
@@ -53,8 +55,10 @@ export function trackBackfillProxies() {
     } else {
       body = text;
     }
-    cachePut(key, { at: Date.now(), status: upstream.status, body });
-    res.statusCode = upstream.status;
+    // Cache the 502 like any upstream error: /tracks/all costs OpenSky
+    // credits, so a retry inside the window must not re-download the body.
+    cachePut(key, { at: Date.now(), status, body });
+    res.statusCode = status;
     res.setHeader('Content-Type', 'application/json; charset=utf-8');
     res.setHeader('Cache-Control', 'no-store');
     res.end(body);
diff --git a/src/tooling/liveProviders.test.mjs b/src/tooling/liveProviders.test.mjs
index 250924b42..38953eff9 100644
--- a/src/tooling/liveProviders.test.mjs
+++ b/src/tooling/liveProviders.test.mjs
@@ -353,3 +353,31 @@ test('military cooldown bounds untrusted Retry-After and defaults server errors'
     assert.equal(Number(result.headers['retry-after']), seconds);
   }
 });
+
+test('track backfill proxy returns 502 on an oversized upstream body and caches it as an error', async (t) => {
+  const tracks = install(providers.trackBackfillProxies(), true);
+  let callCount = 0;
+  t.mock.method(globalThis, 'fetch', async () => {
+    callCount++;
+    return {
+      ok: true,
+      status: 200,
+      headers: new Map(),
+      body: (async function* () {
+        yield Buffer.alloc(6 * 1024 * 1024, 'x');
+      })(),
+    };
+  });
+
+  const res1 = await tracks('/api/opensky-track', '?icao24=def456');
+  assert.equal(res1.statusCode, 502);
+  assert.deepEqual(JSON.parse(res1.body), {
+    error: 'Upstream track response too large',
+  });
+
+  // Cached as a 502 (never a 200): a retry inside the window neither
+  // reads as an empty track nor spends OpenSky credits on another download.
+  const res2 = await tracks('/api/opensky-track', '?icao24=def456');
+  assert.equal(res2.statusCode, 502);
+  assert.equal(callCount, 1);
+});