diff --git a/tasks/flightradar24/ingest/preprocess/main.py b/tasks/flightradar24/ingest/preprocess/main.py
index 79805ca..03ee4a9 100644
--- a/tasks/flightradar24/ingest/preprocess/main.py
+++ b/tasks/flightradar24/ingest/preprocess/main.py
@@ -309,6 +309,7 @@ def process_batch(conn, packets: list, aircraft_state: dict) -> int:
                 aircraft_state[icao24]["vrate"] = float(parsed["vrate"])
             if onground is not None:
                 aircraft_state[icao24]["onground"] = onground
+            aircraft_state[icao24]["velocity_ts"] = observed_at
 
         # update onground from any message
         if onground is not None and icao24 in aircraft_state:
@@ -317,11 +318,17 @@ def process_batch(conn, packets: list, aircraft_state: dict) -> int:
         # for MSG3: enrich with cached velocity
         if msg_type == "3":
             cached = aircraft_state.get(icao24, {})
-            if speed is None:
+            velocity_ts = cached.get("velocity_ts")
+            # use cached velocity only if it's fresh (< 30 sec old)
+            velocity_fresh = (
+                velocity_ts is not None and
+                (observed_at - velocity_ts).total_seconds() < 30
+            )
+            if speed is None and velocity_fresh:
                 speed = cached.get("speed")
-            if heading is None:
+            if heading is None and velocity_fresh:
                 heading = cached.get("heading")
-            if vrate is None:
+            if vrate is None and velocity_fresh:
                 vrate = cached.get("vrate")
             if onground is None:
                 onground = cached.get("onground")