diff --git a/server/src/flights/adsb.ts b/server/src/flights/adsb.ts
index 161e6d5..ffa9287 100644
--- a/server/src/flights/adsb.ts
+++ b/server/src/flights/adsb.ts
@@ -83,7 +83,7 @@ export async function fetchAdsb(
     );
     return null;
   }
-  const body = await getJson<AircraftEnvelope>(url);
+  const body = await getJson<AircraftEnvelope>(url, { timeoutMs: ADSB_TIMEOUT_MS });
   if (body === null) return null;
   return normalise(body, (dropped) =>
     log?.warn(`flights:adsb: feed sent ${dropped + MAX_ROWS} aircraft; kept the first ${MAX_ROWS}`),
@@ -126,6 +126,30 @@ export async function readDump1090(path: string, log?: AdsbLog): Promise<Flights
  */
 const MAX_ROWS = 5000;
 
+/**
+ * How long this one upstream is given to answer, overriding `http.ts`'s 6 s.
+ *
+ * Not a guess. Five consecutive calls to `api.adsb.lol/v2/point` measured from
+ * the box that actually serves this deployment came back in 1.2 s, 5.7 s,
+ * 24.3 s, 3.5 s and 4.2 s — all of them `200`, none of them wrong, and three of
+ * the five outside the shared default. The feed is a volunteer-run aggregator
+ * answering a geographic query, and its tail is long in a way an NWS
+ * observation's is not.
+ *
+ * The failure that caused was invisible in the worst way: the request did not
+ * error, it timed out, and `flights/index.ts` did exactly what it should with a
+ * `null` — served the simulated plan. So the sky over California quietly stopped
+ * being real for whoever loaded the page in that window, the health endpoint
+ * still reported `flights: adsb` because the *source* was configured and
+ * reachable, and `degraded[]` stayed empty because nothing was degraded at boot.
+ *
+ * 25 s is above the slowest measured answer. It costs nothing when the feed is
+ * quick, because this runs behind `createUpstream`'s TTL and not on the request
+ * path of every visitor, and a slow real answer is worth more than a fast
+ * fabricated one on a board whose whole claim is that the aircraft are live.
+ */
+const ADSB_TIMEOUT_MS = 25_000;
+
 /**
  * One envelope, turned into a snapshot — or `null` if it is not an envelope.
  *