Apparatus

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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
No current signal · last broadcast 5d ago
Flights observed
189
Distinct callsigns
20
Country
US
Last broadcast
5d ago

Last known position

Most recent position reported by Mode-S A54535.

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 - 28 2026-06-27
GTI8173 - 15 2026-06-25
GTI518 - 15 2026-07-09
GTI517 - 11 2026-07-07
GTI812 Atlas Air 9 2026-06-03
GTI365 Atlas Air 7 2026-06-13
GTI8439 Atlas Air 6 2026-04-17
GTI8577 - 5 2026-07-04
GTI8193 Atlas Air 5 2026-05-21
GTI364 Atlas Air 5 2026-06-12
GTI8523 Atlas Air 4 2026-06-01
GTI8275 Atlas Air 4 2026-06-20
GTI8002 Atlas Air 4 2026-04-28
GTI8948 - 3 2026-06-18
GTI8679 - 3 2026-06-06
GTI8554 Atlas Air 3 2026-05-18
GTI8318 Atlas Air 3 2026-04-30
GTI8296 Atlas Air 3 2026-06-28
GTI8292 Atlas Air 3 2026-05-30
GTI8274 Atlas Air 3 2026-06-19

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-09 GTI518 - Jul 9, 00:05 UTCJul 9, 07:45 UTC7h 40m
2026-07-08 GTI518 - Jul 8, 01:20 UTCJul 9, 01:15 UTC23h 55m
2026-07-07 GTI517 - Jul 7, 12:55 UTCJul 8, 02:05 UTC13h 10m
2026-07-07 GTI518 ANC → ORD Jul 7, 04:45 UTCJul 7, 10:10 UTC5h 25m
2026-07-06 GTI518 - Jul 6, 10:50 UTCJul 7, 02:55 UTC16h 5m
2026-07-06 GTI518 - Jul 6, 05:20 UTCJul 7, 02:55 UTC21h 35m
2026-07-06 GTI517 - Jul 6, 04:40 UTCJul 7, 02:55 UTC22h 15m
2026-07-06 GTI517 - Jul 6, 01:20 UTCJul 7, 01:15 UTC23h 55m
2026-07-06 GTI517 - Jul 6, 00:00 UTCJul 6, 20:55 UTC20h 55m
2026-07-05 GTI8500 SUU → PSM Jul 5, 03:05 UTCJul 5, 04:20 UTC1h 15m
2026-07-04 GTI8577 ANC → CVG Jul 4, 15:30 UTCJul 4, 21:20 UTC5h 50m
2026-07-04 GTI8577 - Jul 4, 06:15 UTCJul 4, 13:40 UTC7h 25m
2026-07-04 GTI8577 - Jul 4, 04:50 UTCJul 4, 05:05 UTC15m
2026-07-03 GTI8576 - Jul 3, 22:45 UTCJul 4, 00:55 UTC2h 10m
2026-06-28 GTI8296 NGU → HHN Jun 28, 19:49 UTCJun 28, 20:09 UTC20m
2026-06-28 GTI8296 NGU → HHN Jun 28, 02:05 UTCJun 28, 19:09 UTC17h 5m
2026-06-27 GTI8296 NGU → HHN Jun 27, 14:05 UTCJun 27, 23:00 UTC8h 55m
2026-06-27 GTI8174 - Jun 27, 08:44 UTCJun 27, 10:19 UTC1h 35m
2026-06-26 GTI8174 - Jun 26, 23:04 UTCJun 27, 04:29 UTC5h 25m
2026-06-26 GTI8174 - Jun 26, 04:30 UTCJun 26, 20:24 UTC15h 55m
2026-06-25 GTI8174 - Jun 25, 23:19 UTCJun 26, 20:24 UTC21h 5m
2026-06-25 GTI8173 - Jun 25, 21:20 UTCJun 26, 20:24 UTC23h 5m
2026-06-25 GTI8173 - Jun 25, 19:20 UTCJun 26, 19:09 UTC23h 50m
2026-06-25 GTI8173 - Jun 25, 17:49 UTCJun 26, 14:29 UTC20h 40m
2026-06-25 GTI8174 - Jun 25, 13:05 UTCJun 25, 14:34 UTC1h 30m
2026-06-25 GTI8174 - Jun 25, 11:30 UTCJun 25, 11:39 UTC10m
2026-06-25 GTI8174 - Jun 25, 01:40 UTCJun 25, 07:30 UTC5h 50m
2026-06-24 GTI8174 - Jun 24, 16:14 UTCJun 24, 23:40 UTC7h 25m
2026-06-23 GTI8173 - Jun 23, 04:25 UTCJun 23, 16:39 UTC12h 15m
2026-06-22 GTI8174 - Jun 22, 18:04 UTCJun 22, 21:10 UTC3h 5m
2026-06-22 GTI8174 - Jun 22, 08:19 UTCJun 22, 14:14 UTC5h 55m
2026-06-21 GTI8174 - Jun 21, 11:20 UTCJun 22, 06:35 UTC19h 15m
2026-06-21 GTI8173 - Jun 21, 10:44 UTCJun 22, 06:35 UTC19h 50m
2026-06-21 GTI8173 - Jun 21, 07:20 UTCJun 22, 06:35 UTC23h 15m
2026-06-21 GTI8173 - Jun 21, 06:40 UTCJun 22, 05:15 UTC22h 35m
2026-06-20 GTI8275 HNL → BNE Jun 20, 08:49 UTCJun 20, 13:14 UTC4h 25m
2026-06-19 GTI8275 HNL → BNE Jun 19, 14:19 UTCJun 20, 06:49 UTC16h 30m
2026-06-19 GTI8274 NLU → AUS Jun 19, 05:19 UTCJun 20, 05:14 UTC23h 55m
2026-06-19 GTI8274 NLU → AUS Jun 19, 04:50 UTCJun 20, 00:49 UTC20h 0m
2026-06-18 GTI8592 - Jun 18, 12:35 UTCJun 18, 16:25 UTC3h 50m
2026-06-18 GTI8948 ANC → ORD Jun 18, 03:55 UTCJun 18, 09:30 UTC5h 35m
2026-06-17 GTI8948 ICN → ANC Jun 17, 18:10 UTCJun 18, 01:40 UTC7h 30m
2026-06-17 GTI8948 - Jun 17, 14:30 UTCJun 17, 15:20 UTC50m
2026-06-17 GTI8947 - Jun 17, 07:50 UTCJun 17, 08:15 UTC25m
2026-06-15 GTI8675 - Jun 15, 20:45 UTCJun 16, 10:09 UTC13h 25m
2026-06-15 GTI518 - Jun 15, 09:35 UTCJun 15, 14:50 UTC5h 15m
2026-06-14 GTI518 - Jun 14, 16:50 UTCJun 15, 07:20 UTC14h 29m
2026-06-14 GTI518 - Jun 14, 11:20 UTCJun 15, 07:20 UTC19h 59m
2026-06-14 GTI517 ANC → ICN Jun 14, 09:20 UTCJun 15, 07:20 UTC22h 0m
2026-06-14 GTI517 ANC → ICN Jun 14, 07:30 UTCJun 15, 07:15 UTC23h 44m

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 .

Mode-S A54535 frequently asked

What is Mode-S code A54535?
A54535 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N439GT.
Where is Mode-S A54535 registered?
Mode-S code A54535 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 A54535 broadcasting right now?
No active broadcast right now. Last signal was 5d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A54535, octal 51242465, decimal 10,831,157.
What flights does A54535 operate?
Mode-S A54535 has broadcast 20 distinct callsigns, including GTI8174, GTI8173, GTI518, GTI517, GTI812.