Apparatus

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sensors Mode-S transponder

A2ADF4

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N272AK · BOEING 737-900 · operated by ALASKA AIRLINES INC

Hex
A2ADF4
Octal
50526764
Decimal
10,661,364
Country
US
Tail
N272AK
Type
B739
No current signal · last broadcast 3h ago
Flights observed
353
Distinct callsigns
20
Country
US
Last broadcast
3h ago

Last known position

Most recent position reported by Mode-S A2ADF4.

Country allocation

The ICAO 24-bit address A2ADF4 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
ASA767 Alaska Airlines 6 2026-05-07
ASA787 - 4 2026-06-21
ASA535 - 4 2026-07-06
ASA522 Alaska Airlines 4 2026-06-29
ASA500 - 4 2026-07-13
ASA379 - 4 2026-07-11
ASA378 - 4 2026-07-11
ASA329 Alaska Airlines 4 2026-05-23
AS412 - 4 2026-04-15
ASA723 Alaska Airlines 3 2026-05-16
ASA719 Alaska Airlines 3 2026-05-22
ASA716 Alaska Airlines 3 2026-06-24
ASA69 Alaska Airlines 3 2026-05-28
ASA638 Alaska Airlines 3 2026-05-07
ASA612 - 3 2026-07-08
ASA60 Alaska Airlines 3 2026-05-28
ASA584 Alaska Airlines 3 2026-06-04
ASA460 - 3 2026-07-08
ASA415 Alaska Airlines 3 2026-04-16
ASA414 - 3 2026-04-16

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-13 ASA500 - Jul 13, 21:45 UTCJul 14, 01:45 UTC4h 0m
2026-07-13 ASA500 - Jul 13, 16:40 UTCJul 13, 20:20 UTC3h 40m
2026-07-13 ASA473 STL → SEA Jul 13, 11:10 UTCJul 13, 14:40 UTC3h 30m
2026-07-13 ASA473 STL → SEA Jul 13, 11:07 UTCJul 13, 14:33 UTC3h 26m
2026-07-13 ASA615 SEA → STL Jul 13, 01:15 UTCJul 13, 04:40 UTC3h 25m
2026-07-13 ASA615 SEA → STL Jul 13, 01:15 UTCJul 13, 04:35 UTC3h 20m
2026-07-12 ASA618 STL → SEA Jul 12, 20:01 UTCJul 12, 23:45 UTC3h 45m
2026-07-12 ASA618 SEA → STL Jul 12, 15:10 UTCJul 12, 18:25 UTC3h 15m
2026-07-11 ASA379 - Jul 11, 22:35 UTCJul 12, 03:35 UTC5h 0m
2026-07-11 ASA378 SEA → BWI Jul 11, 16:20 UTCJul 11, 20:55 UTC4h 35m
2026-07-11 ASA387 MSP → SEA Jul 11, 11:20 UTCJul 11, 14:30 UTC3h 10m
2026-07-10 ASA527 SNA → SEA Jul 10, 21:05 UTCJul 11, 00:00 UTC2h 55m
2026-07-10 ASA338 BOS → SEA Jul 10, 13:25 UTCJul 10, 18:50 UTC5h 25m
2026-07-10 ASA1431 SAN → SEA Jul 10, 01:46 UTCJul 10, 03:58 UTC2h 12m
2026-07-09 ASA251 GEG → PDX Jul 9, 19:55 UTCJul 9, 20:45 UTC50m
2026-07-09 ASA251 GEG → PDX Jul 9, 19:55 UTCJul 10, 19:00 UTC23h 5m
2026-07-09 ASA250 PDX → GEG Jul 9, 17:35 UTCJul 9, 18:20 UTC45m
2026-07-09 ASA311 SEA → SFO Jul 9, 10:30 UTCJul 9, 16:00 UTC5h 30m
2026-07-08 ASA460 SEA → BOS Jul 8, 22:50 UTCJul 9, 03:35 UTC4h 45m
2026-07-08 ASA785 LAS → SEA Jul 8, 19:05 UTCJul 8, 21:10 UTC2h 5m
2026-07-08 ASA612 SEA → LAS Jul 8, 15:15 UTCJul 8, 17:10 UTC1h 55m
2026-07-08 ASA612 SEA → LAS Jul 8, 15:13 UTCJul 8, 17:08 UTC1h 55m
2026-07-08 ASA591 CUN → SFO Jul 8, 04:00 UTCJul 8, 05:30 UTC1h 30m
2026-07-08 ASA504 OAK → SEA Jul 8, 01:15 UTCJul 8, 02:45 UTC1h 30m
2026-07-07 ASA1315 - Jul 7, 21:55 UTCJul 7, 23:50 UTC1h 55m
2026-07-07 ASA695 SJC → PDX Jul 7, 18:30 UTCJul 7, 20:25 UTC1h 55m
2026-07-07 ASA1626 DEN → PDX Jul 7, 14:20 UTCJul 7, 16:40 UTC2h 20m
2026-07-07 ASA752 ANC → DEN Jul 7, 07:40 UTCJul 7, 12:40 UTC5h 0m
2026-07-07 ASA661 - Jul 7, 02:45 UTCJul 7, 03:00 UTC15m
2026-07-07 ASA661 SEA → ANC Jul 7, 02:44 UTCJul 7, 05:27 UTC2h 43m
2026-07-06 ASA535 DEN → SEA Jul 6, 23:00 UTCJul 7, 01:20 UTC2h 20m
2026-07-06 ASA535 DEN → SEA Jul 6, 23:02 UTCJul 7, 01:12 UTC2h 10m
2026-07-06 ASA535 SEA → DEN Jul 6, 19:15 UTCJul 6, 21:30 UTC2h 15m
2026-07-06 ASA241 - Jul 6, 13:15 UTCJul 6, 17:20 UTC4h 5m
2026-07-06 ASA398 - Jul 6, 07:20 UTCJul 6, 11:05 UTC3h 45m
2026-07-06 ASA282 - Jul 6, 03:55 UTCJul 6, 05:30 UTC1h 35m
2026-07-06 ASA393 - Jul 6, 00:55 UTCJul 6, 02:35 UTC1h 40m
2026-07-05 ASA418 - Jul 5, 20:00 UTCJul 5, 23:10 UTC3h 10m
2026-07-05 ASA418 - Jul 5, 15:55 UTCJul 5, 18:50 UTC2h 55m
2026-07-04 ASA1464 OAK → SEA Jul 4, 22:55 UTCJul 5, 00:25 UTC1h 30m
2026-07-04 ASA1328 SEA → SFO Jul 4, 20:15 UTCJul 4, 21:55 UTC1h 40m
2026-07-04 ASA512 - Jul 4, 14:45 UTCJul 4, 17:10 UTC2h 25m
2026-07-03 ASA474 - Jul 3, 23:30 UTCJul 4, 04:15 UTC4h 45m
2026-07-03 ASA434 - Jul 3, 17:25 UTCJul 3, 21:50 UTC4h 25m
2026-07-03 ASA1623 SJC → SAN Jul 3, 14:59 UTCJul 3, 16:03 UTC1h 4m
2026-07-03 ASA1623 SJC → SAN Jul 3, 15:00 UTCJul 3, 16:10 UTC1h 10m
2026-07-03 ASA678 PDX → SJC Jul 3, 04:50 UTCJul 3, 06:10 UTC1h 20m
2026-07-03 ASA678 PDX → SJC Jul 3, 04:50 UTCJul 3, 06:05 UTC1h 15m
2026-07-02 ASA290 - Jul 2, 21:30 UTCJul 3, 02:40 UTC5h 10m
2026-07-02 ASA294 - Jul 2, 19:40 UTCJul 2, 19:45 UTC5m

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 N272AK page for operator, model, and routing details .

Mode-S A2ADF4 frequently asked

What is Mode-S code A2ADF4?
A2ADF4 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N272AK.
Where is Mode-S A2ADF4 registered?
Mode-S code A2ADF4 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 A2ADF4 broadcasting right now?
No active broadcast right now. Last signal was 3h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A2ADF4, octal 50526764, decimal 10,661,364.
What flights does A2ADF4 operate?
Mode-S A2ADF4 has broadcast 20 distinct callsigns, including ASA767, ASA787, ASA535, ASA522, ASA500.