Apparatus

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sensors Mode-S transponder

A561FD

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N446MC · BOEING 747-400 · operated by ATLAS AIR INC

Hex
A561FD
Octal
51260775
Decimal
10,838,525
Country
US
Tail
N446MC
Type
B744
No current signal · last broadcast 2h ago
Flights observed
20
Distinct callsigns
3
Country
US
Last broadcast
2h ago

Last known position

Most recent position reported by Mode-S A561FD.

Country allocation

The ICAO 24-bit address A561FD falls within the block assigned to United States (US) by ICAO Annex 10, Volume III. Every aircraft registered in United States receives a permanent address from this block at the time of registration; the address stays with the airframe even if the aircraft is re-registered to a different operator within the country.

Callsign history 3 distinct

Callsign Airline Flights Last seen
GTI512 Atlas Air 13 2026-04-18
GTI8028 Atlas Air 5 2026-04-16
GTI511 Atlas Air 2 2026-04-17

Recent flights last 20

DateFlightRouteTakeoffLandingDuration
2026-04-18 GTI512 ANC → ORD Apr 18, 14:20 UTCApr 18, 21:15 UTC6h 55m
2026-04-17 GTI511 ORD → ICN Apr 17, 23:45 UTCApr 18, 12:15 UTC12h 30m
2026-04-17 GTI512 ANC → ORD Apr 17, 19:25 UTCApr 17, 20:40 UTC1h 15m
2026-04-17 GTI512 ANC → ORD Apr 17, 19:10 UTCApr 17, 19:20 UTC10m
2026-04-17 GTI512 ANC → ORD Apr 17, 14:15 UTCApr 17, 14:30 UTC15m
2026-04-17 GTI512 ANC → ORD Apr 17, 13:20 UTCApr 17, 13:30 UTC10m
2026-04-17 GTI512 ANC → ORD Apr 17, 11:20 UTCApr 17, 12:50 UTC1h 30m
2026-04-17 GTI512 ANC → ORD Apr 17, 09:20 UTCApr 17, 11:15 UTC1h 55m
2026-04-17 GTI512 ANC → ORD Apr 17, 07:40 UTCApr 17, 09:15 UTC1h 35m
2026-04-17 GTI512 ANC → ORD Apr 17, 04:00 UTCApr 17, 05:15 UTC1h 16m
2026-04-16 GTI512 ANC → ORD Apr 16, 23:20 UTCApr 16, 23:45 UTC25m
2026-04-16 GTI512 ANC → ORD Apr 16, 22:24 UTCApr 16, 23:10 UTC45m
2026-04-16 GTI511 ORD → ICN Apr 16, 17:15 UTCApr 16, 17:44 UTC30m
2026-04-16 GTI8028 LAX → ICN Apr 16, 13:15 UTCApr 16, 15:05 UTC1h 50m
2026-04-16 GTI8028 LAX → ICN Apr 16, 07:09 UTCApr 16, 08:45 UTC1h 35m
2026-04-16 GTI8028 LAX → ICN Apr 16, 05:09 UTCApr 16, 07:05 UTC1h 55m
2026-04-16 GTI8028 LAX → ICN Apr 16, 03:09 UTCApr 16, 05:05 UTC1h 55m
2026-04-16 GTI8028 LAX → ICN Apr 16, 01:10 UTCApr 16, 03:04 UTC1h 55m
2026-04-14 GTI512 ANC → ORD Apr 14, 18:55 UTCApr 14, 19:45 UTC50m
2026-04-14 GTI512 ANC → ORD Apr 14, 18:15 UTCApr 14, 18:45 UTC30m

About Mode-S

A Mode-S transponder code (also called an "ICAO 24-bit address" or "hex code") is a 6-character hexadecimal identifier permanently assigned to an aircraft when it's first registered. Unlike callsigns (which change with each flight) or registrations (which can change if an aircraft is sold internationally), the Mode-S address stays with the airframe for the life of the aircraft in that country.

Every ADS-B transmission from an aircraft includes its Mode-S address, making it the most reliable way to identify a specific airframe. Flight-tracking services like Apparatus use the Mode-S address as the primary key for tying position broadcasts, callsigns, and ownership records together.

Prefer a tail-number view? See the N446MC page for operator, model, and routing details .

Mode-S A561FD frequently asked

What is Mode-S code A561FD?
A561FD is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N446MC.
Where is Mode-S A561FD registered?
Mode-S code A561FD is allocated to United States (US). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is A561FD broadcasting right now?
No active broadcast right now. Last signal was 2h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A561FD, octal 51260775, decimal 10,838,525.
What flights does A561FD operate?
Mode-S A561FD has broadcast 3 distinct callsigns, including GTI512, GTI8028, GTI511.