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
- Flights observed
- 91
- Distinct callsigns
- 20
- Country
- US
- Last broadcast
- 3h ago
Last known position
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 20 distinct
| Callsign | Airline | Flights | Last seen |
|---|---|---|---|
| GTI512 | Atlas Air | 15 | 2026-04-19 |
| GTI8560 | Atlas Air | 9 | 2026-06-01 |
| GTI8559 | Atlas Air | 6 | 2026-06-01 |
| GTI8028 | Atlas Air | 5 | 2026-04-16 |
| GTI8857 | Atlas Air | 3 | 2026-04-23 |
| GTI8824 | Atlas Air | 3 | 2026-05-27 |
| GTI8676 | Atlas Air | 3 | 2026-04-25 |
| GTI8551 | Atlas Air | 3 | 2026-05-11 |
| GTI8243 | Atlas Air | 3 | 2026-05-18 |
| GTI8242 | Atlas Air | 3 | 2026-06-03 |
| GTI8193 | Atlas Air | 3 | 2026-05-30 |
| GTI812 | Atlas Air | 3 | 2026-05-13 |
| GTI5579 | Atlas Air | 3 | 2026-05-05 |
| GTI518 | Atlas Air | 3 | 2026-05-25 |
| GTI511 | Atlas Air | 3 | 2026-04-19 |
| GTI8825 | Atlas Air | 2 | 2026-05-28 |
| GTI8692 | Atlas Air | 2 | 2026-05-06 |
| GTI8106 | Atlas Air | 2 | 2026-05-09 |
| GTI8021 | Atlas Air | 2 | 2026-05-07 |
| GTI517 | Atlas Air | 2 | 2026-05-24 |
Recent flights last 50
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-06-03 | GTI8242 | IND → HHN | Jun 3, 06:35 UTC | Jun 3, 07:00 UTC | 25m |
| 2026-06-02 | GTI8242 | IND → HHN | Jun 2, 22:15 UTC | Jun 3, 02:10 UTC | 3h 55m |
| 2026-06-02 | GTI8242 | IND → HHN | Jun 2, 05:10 UTC | Jun 2, 18:15 UTC | 13h 5m |
| 2026-06-01 | GTI8560 | ANC → DFW | Jun 1, 21:15 UTC | Jun 2, 02:40 UTC | 5h 25m |
| 2026-06-01 | GTI8560 | ANC → DFW | Jun 1, 10:40 UTC | Jun 1, 17:55 UTC | 7h 15m |
| 2026-06-01 | GTI8559 | GRK → SEA | Jun 1, 03:00 UTC | Jun 1, 03:15 UTC | 15m |
| 2026-05-31 | GTI8559 | GRK → SEA | May 31, 20:30 UTC | Jun 1, 00:25 UTC | 3h 55m |
| 2026-05-31 | GTI8559 | GRK → SEA | May 31, 12:05 UTC | May 31, 14:20 UTC | 2h 15m |
| 2026-05-31 | GTI8559 | GRK → SEA | May 31, 01:10 UTC | May 31, 01:11 UTC | 1m |
| 2026-05-30 | GTI8193 | YYZ → DFW | May 30, 06:30 UTC | May 30, 12:15 UTC | 5h 45m |
| 2026-05-29 | GTI8193 | YYZ → DFW | May 29, 20:35 UTC | May 30, 03:35 UTC | 7h 0m |
| 2026-05-29 | GTI8193 | YYZ → DFW | May 29, 18:05 UTC | May 29, 18:40 UTC | 35m |
| 2026-05-29 | GTI8192 | DFW → HKG | May 29, 08:50 UTC | May 29, 09:15 UTC | 25m |
| 2026-05-28 | GTI8825 | HHN → BWI | May 28, 06:20 UTC | May 28, 21:25 UTC | 15h 5m |
| 2026-05-27 | GTI8825 | HHN → BWI | May 27, 19:45 UTC | May 28, 02:50 UTC | 7h 5m |
| 2026-05-27 | GTI8824 | BWI → HHN | May 27, 14:20 UTC | May 27, 15:25 UTC | 1h 5m |
| 2026-05-27 | GTI8824 | BWI → HHN | May 27, 01:44 UTC | May 27, 09:15 UTC | 7h 30m |
| 2026-05-26 | GTI8824 | BWI → HHN | May 26, 18:10 UTC | May 26, 19:34 UTC | 1h 25m |
| 2026-05-25 | GTI518 | ANC → ORD | May 25, 08:20 UTC | May 25, 13:40 UTC | 5h 20m |
| 2026-05-24 | GTI518 | ANC → ORD | May 24, 14:35 UTC | May 25, 06:40 UTC | 16h 5m |
| 2026-05-24 | GTI518 | ANC → ORD | May 24, 09:20 UTC | May 25, 06:40 UTC | 21h 20m |
| 2026-05-24 | GTI517 | ANC → ICN | May 24, 08:00 UTC | May 25, 06:40 UTC | 22h 40m |
| 2026-05-24 | GTI517 | ANC → ICN | May 24, 03:20 UTC | May 24, 23:46 UTC | 20h 26m |
| 2026-05-23 | GTI8560 | ANC → DFW | May 23, 08:00 UTC | May 23, 13:25 UTC | 5h 25m |
| 2026-05-22 | GTI8560 | ANC → DFW | May 22, 22:45 UTC | May 23, 05:35 UTC | 6h 49m |
| 2026-05-22 | GTI8560 | ANC → DFW | May 22, 09:20 UTC | May 23, 05:35 UTC | 20h 14m |
| 2026-05-22 | GTI8560 | ANC → DFW | May 22, 09:05 UTC | May 23, 05:35 UTC | 20h 29m |
| 2026-05-21 | GTI8559 | GRK → SEA | May 21, 16:35 UTC | May 22, 06:15 UTC | 13h 40m |
| 2026-05-18 | GTI8243 | HHN → PSM | May 18, 05:05 UTC | May 18, 10:55 UTC | 5h 50m |
| 2026-05-17 | GTI8243 | HHN → PSM | May 17, 19:10 UTC | May 18, 02:25 UTC | 7h 15m |
| 2026-05-17 | GTI8243 | HHN → PSM | May 17, 00:10 UTC | May 17, 20:30 UTC | 20h 20m |
| 2026-05-16 | GTI824D | ORD → ICN | May 16, 08:31 UTC | May 16, 21:15 UTC | 12h 45m |
| 2026-05-15 | GTI8560 | ANC → DFW | May 15, 20:20 UTC | May 16, 01:55 UTC | 5h 35m |
| 2026-05-15 | GTI8560 | ANC → DFW | May 15, 10:55 UTC | May 15, 18:25 UTC | 7h 29m |
| 2026-05-14 | GTI8560 | ANC → DFW | May 14, 20:25 UTC | May 15, 18:25 UTC | 21h 59m |
| 2026-05-13 | GTI8559 | GRK → SEA | May 13, 20:35 UTC | May 14, 09:50 UTC | 13h 15m |
| 2026-05-13 | GTI812 | PVG → ANC | May 13, 16:20 UTC | May 13, 17:30 UTC | 1h 10m |
| 2026-05-13 | GTI812 | PVG → ANC | May 13, 09:05 UTC | May 13, 14:30 UTC | 5h 25m |
| 2026-05-12 | GTI812 | PVG → ANC | May 12, 16:25 UTC | May 13, 06:10 UTC | 13h 45m |
| 2026-05-11 | GTI9925 | ANC → HKG | May 11, 21:10 UTC | May 11, 21:25 UTC | 15m |
| 2026-05-11 | GTI8551 | HHN → PSM | May 11, 04:35 UTC | May 11, 15:20 UTC | 10h 45m |
| 2026-05-10 | GTI8551 | HHN → PSM | May 10, 16:44 UTC | May 11, 01:55 UTC | 9h 10m |
| 2026-05-10 | GTI8551 | HHN → PSM | May 10, 09:40 UTC | May 10, 11:55 UTC | 2h 15m |
| 2026-05-09 | GTI8106 | ANC → DFW | May 9, 12:15 UTC | May 9, 19:25 UTC | 7h 10m |
| 2026-05-09 | GTI8106 | ANC → DFW | May 9, 03:50 UTC | May 9, 10:20 UTC | 6h 30m |
| 2026-05-07 | GTI8107 | ANC → ICN | May 7, 16:55 UTC | May 7, 17:20 UTC | 25m |
| 2026-05-07 | GTI8021 | MIA → YMX | May 7, 00:35 UTC | May 7, 14:45 UTC | 14h 10m |
| 2026-05-06 | GTI8021 | MIA → YMX | May 6, 18:00 UTC | May 6, 21:00 UTC | 3h 0m |
| 2026-05-06 | GTI8692 | ANC → GDL | May 6, 00:35 UTC | May 6, 13:30 UTC | 12h 55m |
| 2026-05-05 | GTI8692 | ANC → GDL | May 5, 13:40 UTC | May 5, 22:35 UTC | 8h 55m |
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 .