sensors Mode-S transponder
A54535
ICAO 24-bit transponder address · allocated to United States
Currently assigned to N439GT · operated by ATLAS AIR INC
- Hex
- A54535
- Octal
- 51242465
- Decimal
- 10,831,157
- Country
- US
- Tail
- N439GT
- Type
- B744
- Flights observed
- 111
- Distinct callsigns
- 20
- Country
- US
- Last broadcast
- 26m ago
Last known position
Country allocation
The ICAO 24-bit address A54535 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 |
|---|---|---|---|
| GTI8174 | Atlas Air | 17 | 2026-05-15 |
| GTI8173 | Atlas Air | 8 | 2026-05-14 |
| GTI8439 | Atlas Air | 6 | 2026-04-17 |
| GTI812 | Atlas Air | 6 | 2026-04-13 |
| GTI8193 | Atlas Air | 5 | 2026-05-21 |
| GTI518 | Atlas Air | 5 | 2026-05-07 |
| GTI8002 | Atlas Air | 4 | 2026-04-28 |
| GTI517 | Atlas Air | 4 | 2026-05-05 |
| GTI8554 | Atlas Air | 3 | 2026-05-18 |
| GTI8318 | Atlas Air | 3 | 2026-04-30 |
| GTI8292 | Atlas Air | 3 | 2026-05-30 |
| GTI8243 | Atlas Air | 3 | 2026-05-23 |
| GTI365 | Atlas Air | 3 | 2026-05-02 |
| GTI364 | Atlas Air | 3 | 2026-05-01 |
| CMB541 | - | 3 | 2026-05-19 |
| GTI9942 | Atlas Air | 2 | 2026-05-26 |
| GTI9928 | Atlas Air | 2 | 2026-05-19 |
| GTI8833 | Atlas Air | 2 | 2026-04-25 |
| GTI8662 | Atlas Air | 2 | 2026-05-25 |
| GTI8275 | Atlas Air | 2 | 2026-05-09 |
Recent flights last 50
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-05-30 | GTI8292 | GUA → IAH | May 30, 03:00 UTC | May 30, 05:15 UTC | 2h 15m |
| 2026-05-29 | GTI8292 | GUA → IAH | May 29, 14:05 UTC | May 29, 22:55 UTC | 8h 50m |
| 2026-05-29 | GTI8292 | GUA → IAH | May 29, 08:00 UTC | May 29, 10:00 UTC | 2h 0m |
| 2026-05-28 | GTI8120 | HOP → HHN | May 28, 19:05 UTC | May 29, 00:15 UTC | 5h 10m |
| 2026-05-28 | GTI8120 | HOP → HHN | May 28, 09:50 UTC | May 28, 16:45 UTC | 6h 55m |
| 2026-05-28 | GTI8117 | ORD → ICN | May 28, 03:30 UTC | May 28, 03:50 UTC | 20m |
| 2026-05-27 | GTI8117 | ORD → ICN | May 27, 20:45 UTC | May 28, 00:30 UTC | 3h 45m |
| 2026-05-26 | GTI9942 | MIA → LAX | May 26, 23:05 UTC | May 26, 23:25 UTC | 20m |
| 2026-05-26 | GTI9942 | MIA → LAX | May 26, 11:34 UTC | May 26, 22:29 UTC | 10h 55m |
| 2026-05-25 | GTI8662 | ORD → HIF | May 25, 22:30 UTC | May 26, 07:19 UTC | 8h 50m |
| 2026-05-25 | GTI8662 | ORD → HIF | May 25, 15:05 UTC | May 25, 17:55 UTC | 2h 50m |
| 2026-05-24 | GTI8238 | FRA → ORD | May 24, 19:00 UTC | May 25, 03:45 UTC | 8h 45m |
| 2026-05-24 | GTI8237 | ORD → FRA | May 24, 07:30 UTC | May 24, 15:25 UTC | 7h 55m |
| 2026-05-23 | GTI8243 | HHN → PSM | May 23, 21:20 UTC | May 24, 02:35 UTC | 5h 15m |
| 2026-05-23 | GTI8243 | HHN → PSM | May 23, 11:35 UTC | May 23, 18:40 UTC | 7h 6m |
| 2026-05-22 | GTI8243 | HHN → PSM | May 22, 20:35 UTC | May 23, 18:40 UTC | 22h 5m |
| 2026-05-21 | GTI8242 | IND → HHN | May 21, 22:10 UTC | May 22, 11:40 UTC | 13h 30m |
| 2026-05-21 | GTI8193 | YYZ → DFW | May 21, 07:05 UTC | May 21, 12:20 UTC | 5h 15m |
| 2026-05-20 | GTI8193 | YYZ → DFW | May 20, 21:45 UTC | May 21, 05:05 UTC | 7h 20m |
| 2026-05-20 | GTI8193 | YYZ → DFW | May 20, 17:25 UTC | May 20, 19:35 UTC | 2h 10m |
| 2026-05-20 | GTI8192 | DFW → HKG | May 20, 11:00 UTC | May 20, 11:25 UTC | 25m |
| 2026-05-19 | GTI9928 | SOF → ICN | May 19, 21:30 UTC | May 19, 22:00 UTC | 30m |
| 2026-05-19 | GTI9928 | SOF → ICN | May 19, 12:00 UTC | May 19, 20:50 UTC | 8h 50m |
| 2026-05-19 | CMB541 | - | May 19, 05:40 UTC | May 19, 08:25 UTC | 2h 45m |
| 2026-05-19 | CMB541 | - | May 19, 00:15 UTC | May 19, 02:25 UTC | 2h 10m |
| 2026-05-18 | CMB541 | - | May 18, 08:55 UTC | May 18, 19:10 UTC | 10h 14m |
| 2026-05-18 | GTI8554 | PSM → HHN | May 18, 04:11 UTC | May 18, 05:55 UTC | 1h 45m |
| 2026-05-17 | GTI8554 | PSM → HHN | May 17, 09:20 UTC | May 18, 05:55 UTC | 20h 35m |
| 2026-05-17 | GTI8554 | PSM → HHN | May 17, 08:40 UTC | May 18, 05:55 UTC | 21h 15m |
| 2026-05-16 | GTI9460 | MXP → ICN | May 16, 14:05 UTC | May 17, 00:50 UTC | 10h 45m |
| 2026-05-16 | CMB391 | - | May 16, 02:40 UTC | May 16, 10:40 UTC | 8h 1m |
| 2026-05-15 | GTI8504 | ORD → PIT | May 15, 18:50 UTC | May 15, 22:35 UTC | 3h 45m |
| 2026-05-15 | GTI8174 | ANC → NLU | May 15, 09:05 UTC | May 15, 15:05 UTC | 5h 59m |
| 2026-05-14 | GTI8174 | ANC → NLU | May 14, 15:15 UTC | May 15, 07:15 UTC | 16h 0m |
| 2026-05-14 | GTI8174 | ANC → NLU | May 14, 09:20 UTC | May 15, 07:15 UTC | 21h 55m |
| 2026-05-14 | GTI8173 | LAX → PVG | May 14, 05:20 UTC | May 15, 00:50 UTC | 19h 30m |
| 2026-05-14 | GTI8173 | LAX → PVG | May 14, 05:05 UTC | May 15, 00:50 UTC | 19h 45m |
| 2026-05-13 | GTI8174 | ANC → NLU | May 13, 19:05 UTC | May 13, 22:25 UTC | 3h 20m |
| 2026-05-13 | GTI8174 | ANC → NLU | May 13, 09:20 UTC | May 13, 14:45 UTC | 5h 25m |
| 2026-05-12 | GTI8174 | ANC → NLU | May 12, 11:20 UTC | May 13, 06:45 UTC | 19h 25m |
| 2026-05-12 | GTI8174 | ANC → NLU | May 12, 09:55 UTC | May 13, 06:45 UTC | 20h 50m |
| 2026-05-12 | GTI8173 | LAX → PVG | May 12, 07:20 UTC | May 13, 06:45 UTC | 23h 25m |
| 2026-05-12 | GTI8173 | LAX → PVG | May 12, 06:05 UTC | May 13, 05:15 UTC | 23h 10m |
| 2026-05-12 | GTI8294 | SYD → HNL | May 12, 02:45 UTC | May 12, 03:45 UTC | 1h 0m |
| 2026-05-11 | GTI8174 | ANC → NLU | May 11, 07:35 UTC | May 11, 13:20 UTC | 5h 45m |
| 2026-05-10 | GTI8174 | ANC → NLU | May 10, 14:25 UTC | May 11, 05:30 UTC | 15h 5m |
| 2026-05-10 | GTI8174 | ANC → NLU | May 10, 05:20 UTC | May 11, 05:15 UTC | 23h 55m |
| 2026-05-10 | GTI8173 | LAX → PVG | May 10, 04:04 UTC | May 10, 23:35 UTC | 19h 30m |
| 2026-05-09 | GTI8275 | HNL → BNE | May 9, 09:15 UTC | May 9, 13:45 UTC | 4h 30m |
| 2026-05-08 | GTI8275 | HNL → BNE | May 8, 13:50 UTC | May 9, 05:40 UTC | 15h 50m |
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 N439GT page for operator, model, and routing details .