ABOUT OUR DATA

How this data is collected and calculated

Every number on this site comes from somewhere. This page explains where, and where the limits are.

01Data Source

NRT CARGO WATCH is built on public ADS-B (Automatic Dependent Surveillance–Broadcast) data. Aircraft continuously broadcast their position, altitude, heading, and speed, which is picked up by a network of ground receivers within range of Narita Airport and made available through public flight-tracking services.

We monitor a 50 nautical mile radius centered on Narita (RJAA). Coverage depends on receiver placement and terrain, so aircraft flying low or far from any receiver may occasionally be missed.

02How We Identify Dedicated Freighters

Every aircraft we detect is checked against a set of rules based on its callsign, registration, and aircraft type — including known freighter-only carriers, dedicated freighter aircraft types, and specific registrations of aircraft operated by mixed passenger/cargo airlines.

This means our data covers dedicated freighters — aircraft that do not carry passengers. It does not currently include belly-cargo-only charter flights operated on passenger aircraft, which are rare but do occur. We're aware of this gap and may address it in the future.

In short: every flight shown here is a dedicated freighter, but not every cargo movement through Narita is shown here.

03How We Calculate Cargo Capacity (Tons)

Capacity figures on this site are estimates, not measurements. We do not know how much cargo was actually loaded on any given flight — that information isn't broadcast. Instead, each aircraft type is assigned a maximum payload figure based on the specifications published by the airlines that operate it, and capacity is calculated from that figure.

Maximum payload varies by airline even for the same aircraft type, depending on cabin configuration, engine variant, and operating restrictions. The figures below are representative values, not a precise match for every airframe — treat them as a reference for scale, not an exact number.

Reference Payload by Aircraft Type

Type	Max Payload
B748F	133.0 t
MD11F	95.0 t
B744F	113.0 t
B77L / B77W	102.0 t
A333	59.0 t
B763	54.0 t
A306	50.0 t
A321	28.0 t
B738	23.0 t
Other / unlisted types	20.0 t (default)

04Narita's Curfew

Narita operates under a legally mandated curfew: aircraft movements are prohibited from 23:00 to 06:00, with very limited exceptions for the A runway until 24:00 in unavoidable cases. This is why our hourly charts show zero activity overnight — it reflects the airport's operating rules, not a gap in our data.

05Update Frequency & Data Retention

Live figures (today's movements, capacity, active carriers) update continuously throughout the day.
Timestamps are based on detection time within our 50nm radius — not scheduled or actual arrival/departure times.
Trend pages currently show a rolling 90-day window of history.

06Known Limitations

Belly-cargo-only charter flights on passenger aircraft are not currently tracked (see Section 2).
Cargo capacity figures are estimates based on aircraft type, not actual load weights (see Section 3).
ADS-B reception can occasionally miss aircraft due to terrain, distance, or receiver downtime.
Freighter identification relies on maintained lists of carriers, aircraft types, and registrations, which may lag behind real-world changes (new operators, repainted aircraft, etc.).

Spotted something that looks wrong — a misclassified flight, a missing carrier, a rare airframe we mislabeled? Let us know via the Contact page. This kind of feedback directly improves the data.