Apparatus

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sensors Mode-S transponder

AD4AFB

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N956AK · BOEING 737 MAX 9 · operated by BANK OF UTAH TRUSTEE

Hex
AD4AFB
Octal
53245373
Decimal
11,356,923
Country
US
Tail
N956AK
Type
B39M
No current signal · last broadcast 2h ago
Flights observed
369
Distinct callsigns
20
Country
US
Last broadcast
2h ago

Last known position

Most recent position reported by Mode-S AD4AFB.

Country allocation

The ICAO 24-bit address AD4AFB 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
ASA617 Alaska Airlines 7 2026-05-23
ASA508 - 6 2026-06-22
ASA787 Alaska Airlines 5 2026-05-20
ASA502 Alaska Airlines 5 2026-06-08
ASA433 Alaska Airlines 5 2026-05-28
ASA727 - 4 2026-07-07
ASA639 Alaska Airlines 4 2026-04-14
ASA287 - 4 2026-07-09
ASA22 Alaska Airlines 4 2026-06-10
ASA1332 - 4 2026-06-20
ASA795 Alaska Airlines 3 2026-06-15
ASA779 - 3 2026-07-06
ASA776 - 3 2026-07-05
ASA751 Alaska Airlines 3 2026-05-19
ASA657 Alaska Airlines 3 2026-06-04
ASA647 - 3 2026-07-02
ASA643 - 3 2026-07-11
ASA561 Alaska Airlines 3 2026-06-04
ASA500 - 3 2026-07-12
ASA459 - 3 2026-06-26

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-13 ASA313 - Jul 13, 21:45 UTCJul 14, 02:00 UTC4h 15m
2026-07-13 ASA313 SEA → DTW Jul 13, 16:30 UTCJul 13, 20:10 UTC3h 40m
2026-07-13 ASA323 - Jul 13, 13:20 UTCJul 13, 14:35 UTC1h 15m
2026-07-13 ASA736 - Jul 13, 04:55 UTCJul 13, 06:20 UTC1h 25m
2026-07-13 ASA736 SEA → RNO Jul 13, 04:20 UTCJul 13, 06:20 UTC2h 0m
2026-07-12 ASA500 IND → SEA Jul 12, 21:41 UTCJul 13, 01:24 UTC3h 43m
2026-07-12 ASA500 IND → SEA Jul 12, 21:25 UTCJul 13, 01:25 UTC4h 0m
2026-07-12 ASA500 SEA → IND Jul 12, 16:20 UTCJul 12, 19:55 UTC3h 35m
2026-07-11 ASA503 AUS → SEA Jul 11, 21:55 UTCJul 12, 01:40 UTC3h 45m
2026-07-11 ASA503 AUS → SEA Jul 11, 21:54 UTCJul 12, 01:28 UTC3h 34m
2026-07-11 ASA422 SEA → AUS Jul 11, 16:25 UTCJul 11, 20:05 UTC3h 40m
2026-07-11 ASA643 DEN → SEA Jul 11, 12:20 UTCJul 11, 14:45 UTC2h 25m
2026-07-11 ASA310 - Jul 11, 02:35 UTCJul 11, 04:40 UTC2h 5m
2026-07-10 ASA246 - Jul 10, 23:00 UTCJul 11, 00:00 UTC1h 0m
2026-07-10 ASA202 - Jul 10, 02:50 UTCJul 10, 03:50 UTC1h 0m
2026-07-10 ASA202 SEA → OGG Jul 10, 02:49 UTCJul 10, 08:11 UTC5h 22m
2026-07-09 ASA402 ANC → SEA Jul 9, 21:50 UTCJul 10, 00:50 UTC3h 0m
2026-07-09 ASA402 ANC → SEA Jul 9, 21:49 UTCJul 10, 00:41 UTC2h 52m
2026-07-09 ASA53 - Jul 9, 14:45 UTCJul 9, 19:35 UTC4h 50m
2026-07-09 ASA53 LAX → ANC Jul 9, 14:44 UTCJul 9, 19:32 UTC4h 48m
2026-07-09 ASA287 - Jul 9, 00:00 UTCJul 9, 05:00 UTC5h 0m
2026-07-08 ASA477 SEA → EWR Jul 8, 17:50 UTCJul 8, 22:35 UTC4h 45m
2026-07-08 ASA377 ATL → SEA Jul 8, 11:10 UTCJul 8, 15:50 UTC4h 40m
2026-07-07 ASA727 SEA → ATL Jul 7, 23:55 UTCJul 8, 04:25 UTC4h 30m
2026-07-07 ASA1476 SMF → SEA Jul 7, 20:25 UTCJul 7, 21:55 UTC1h 30m
2026-07-07 ASA1380 SEA → SMF Jul 7, 17:30 UTCJul 7, 18:55 UTC1h 25m
2026-07-07 ASA1380 SEA → SMF Jul 7, 17:30 UTCJul 7, 18:54 UTC1h 24m
2026-07-07 ASA377 ATL → SEA Jul 7, 11:25 UTCJul 7, 15:55 UTC4h 30m
2026-07-06 ASA727 SEA → ATL Jul 6, 23:33 UTCJul 7, 03:52 UTC4h 19m
2026-07-06 ASA727 SEA → ATL Jul 6, 23:40 UTCJul 7, 04:00 UTC4h 20m
2026-07-06 ASA676 LAS → SEA Jul 6, 19:25 UTCJul 6, 21:30 UTC2h 5m
2026-07-06 ASA1628 PDX → LAS Jul 6, 16:15 UTCJul 6, 18:05 UTC1h 50m
2026-07-06 ASA779 LAS → PDX Jul 6, 02:05 UTCJul 6, 03:50 UTC1h 45m
2026-07-05 ASA776 HAF → LAS Jul 5, 23:30 UTCJul 6, 00:35 UTC1h 5m
2026-07-05 ASA776 SFO → LAS Jul 5, 23:16 UTCJul 6, 00:27 UTC1h 11m
2026-07-05 ASA655 SEA → SFO Jul 5, 19:05 UTCJul 5, 20:45 UTC1h 40m
2026-07-05 ASA21 JFK → SEA Jul 5, 11:45 UTCJul 5, 17:20 UTC5h 35m
2026-07-05 ASA211 - Jul 5, 04:45 UTCJul 5, 09:45 UTC5h 0m
2026-07-04 ASA421 SEA → SFO Jul 4, 18:20 UTCJul 5, 02:20 UTC8h 0m
2026-07-04 ASA377 ATL → SEA Jul 4, 11:15 UTCJul 4, 16:05 UTC4h 50m
2026-07-03 ASA727 SEA → ATL Jul 3, 23:25 UTCJul 4, 04:00 UTC4h 35m
2026-07-03 ASA676 LAS → SEA Jul 3, 19:30 UTCJul 3, 21:45 UTC2h 15m
2026-07-03 ASA1628 PDX → LAS Jul 3, 16:10 UTCJul 3, 17:55 UTC1h 45m
2026-07-02 ASA1350 - Jul 2, 22:20 UTCJul 3, 02:30 UTC4h 10m
2026-07-02 ASA1345 SEA → BNA Jul 2, 16:25 UTCJul 2, 20:30 UTC4h 5m
2026-07-02 ASA647 STL → SEA Jul 2, 01:20 UTCJul 2, 05:05 UTC3h 45m
2026-07-01 ASA647 SEA → STL Jul 1, 20:15 UTCJul 1, 23:40 UTC3h 25m
2026-07-01 ASA395 MCO → SEA Jul 1, 12:55 UTCJul 1, 18:15 UTC5h 20m
2026-07-01 ASA707 - Jul 1, 04:35 UTCJul 1, 08:55 UTC4h 20m
2026-06-30 ASA25 - Jun 30, 21:50 UTCJul 1, 03:00 UTC5h 10m

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 N956AK page for operator, model, and routing details .

Mode-S AD4AFB frequently asked

What is Mode-S code AD4AFB?
AD4AFB is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N956AK.
Where is Mode-S AD4AFB registered?
Mode-S code AD4AFB 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 AD4AFB 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 AD4AFB, octal 53245373, decimal 11,356,923.
What flights does AD4AFB operate?
Mode-S AD4AFB has broadcast 20 distinct callsigns, including ASA617, ASA508, ASA787, ASA502, ASA433.