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sensors Mode-S transponder

AD1857

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N943AK · operated by ALASKA AIRLINES INC

Hex
AD1857
Octal
53214127
Decimal
11,343,959
Country
US
Tail
N943AK
Type
B39M
Broadcasting now · callsign ASA1459 · 28,225 ft
Flights observed
415
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 21:45 UTC

Current position

AD1857 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address AD1857 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
ASA50 - 11 2026-07-18
ASA49 Alaska Airlines 8 2026-07-18
ASA626 - 7 2026-06-14
ASA581 - 6 2026-07-01
ASA203 - 6 2026-07-06
ASA221 Alaska Airlines 5 2026-05-10
ASA755 Alaska Airlines 4 2026-06-01
ASA62 - 4 2026-07-14
ASA508 Alaska Airlines 4 2026-05-21
ASA418 Alaska Airlines 4 2026-05-15
ASA317 - 4 2026-06-26
ASA270 Alaska Airlines 4 2026-07-26
ASA1403 Alaska Airlines 4 2026-04-17
ASA84 Alaska Airlines 3 2026-05-25
ASA784 Alaska Airlines 3 2026-06-04
ASA763 - 3 2026-07-01
ASA602 - 3 2026-06-26
ASA549 Alaska Airlines 3 2026-04-23
ASA544 Alaska Airlines 3 2026-06-23
ASA535 Alaska Airlines 3 2026-07-24

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 ASA270 SFO → PDX Jul 26, 16:20 UTCJul 26, 21:45 UTC5h 25m
2026-07-26 ASA1332 SAN → BOI Jul 26, 03:45 UTCJul 26, 04:35 UTC50m
2026-07-25 ASA1332 SAN → BOI Jul 25, 23:45 UTCJul 26, 00:00 UTC15m
2026-07-25 ASA270 SFO → PDX Jul 25, 16:25 UTCJul 25, 22:00 UTC5h 35m
2026-07-25 ASA489 MSY → SEA Jul 25, 03:55 UTCJul 25, 06:10 UTC2h 15m
2026-07-24 ASA535 AUS → SFO Jul 24, 23:05 UTCJul 25, 01:25 UTC2h 20m
2026-07-24 ASA535 AUS → SFO Jul 24, 23:00 UTCJul 25, 01:16 UTC2h 16m
2026-07-24 ASA535 AUS → SFO Jul 24, 19:20 UTCJul 24, 21:30 UTC2h 10m
2026-07-24 ASA427 SEA → CVG Jul 24, 17:20 UTCJul 24, 17:55 UTC35m
2026-07-23 ASA1538 SLC → SEA Jul 23, 22:50 UTCJul 24, 02:40 UTC3h 50m
2026-07-23 ASA1538 SLC → SEA Jul 23, 22:49 UTCJul 24, 02:32 UTC3h 43m
2026-07-23 ASA1635 PDX → STL Jul 23, 18:05 UTCJul 23, 21:20 UTC3h 15m
2026-07-23 ASA399 MCO → SFO Jul 23, 14:15 UTCJul 23, 16:15 UTC2h 0m
2026-07-23 ASA1548 ANC → SAN Jul 23, 00:37 UTCJul 23, 05:36 UTC4h 59m
2026-07-23 ASA1548 ANC → SAN Jul 23, 00:40 UTCJul 23, 05:40 UTC5h 0m
2026-07-22 ASA9660 - Jul 22, 19:25 UTCJul 22, 20:15 UTC50m
2026-07-22 ASA9660 SCC → ANC Jul 22, 19:05 UTCJul 22, 20:23 UTC1h 18m
2026-07-22 ASA9661 - Jul 22, 16:40 UTCJul 22, 19:45 UTC3h 5m
2026-07-22 ASA9661 ANC → SCC Jul 22, 16:39 UTCJul 22, 18:19 UTC1h 40m
2026-07-22 ASA1560 - Jul 22, 05:20 UTCJul 22, 05:25 UTC5m
2026-07-22 ASA1560 SEA → ANC Jul 22, 05:16 UTCJul 22, 08:26 UTC3h 10m
2026-07-22 ASA1375 LTO → LAX Jul 22, 00:10 UTCJul 22, 02:10 UTC2h 0m
2026-07-21 ASA1604 SFO → LAX Jul 21, 22:00 UTCJul 21, 22:36 UTC36m
2026-07-21 ASA1604 SFO → LAX Jul 21, 21:50 UTCJul 21, 22:55 UTC1h 5m
2026-07-21 ASA227 SJC → SEA Jul 21, 14:45 UTCJul 21, 20:25 UTC5h 40m
2026-07-21 ASA22 SEA → JFK Jul 21, 10:50 UTCJul 21, 10:55 UTC5m
2026-07-21 ASA22 SEA → JFK Jul 21, 06:35 UTCJul 21, 10:55 UTC4h 20m
2026-07-21 ASA22 SEA → JFK Jul 21, 06:30 UTCJul 21, 10:33 UTC4h 3m
2026-07-21 ASA611 LAX → SEA Jul 21, 02:30 UTCJul 21, 05:00 UTC2h 30m
2026-07-20 ASA515 BOS → PDX Jul 20, 22:10 UTCJul 21, 01:10 UTC2h 59m
2026-07-20 ASA514 PDX → BOS Jul 20, 18:05 UTCJul 20, 20:30 UTC2h 25m
2026-07-20 ASA1349 PDX → PHX Jul 20, 14:35 UTCJul 20, 16:50 UTC2h 15m
2026-07-20 ASA1457 SEA → PDX Jul 20, 05:55 UTCJul 20, 06:25 UTC30m
2026-07-20 ASA249 DEN → SEA Jul 20, 01:05 UTCJul 20, 03:30 UTC2h 25m
2026-07-19 ASA242 SEA → DEN Jul 19, 21:05 UTCJul 19, 23:10 UTC2h 5m
2026-07-19 ASA451 IAD → SFO Jul 19, 15:00 UTCJul 19, 19:20 UTC4h 20m
2026-07-19 ASA451 IAD → SFO Jul 19, 14:59 UTCJul 19, 19:10 UTC4h 11m
2026-07-19 ASA490 SEA → MSY Jul 19, 09:20 UTCJul 19, 13:35 UTC4h 15m
2026-07-19 ASA647 STL → SEA Jul 19, 01:00 UTCJul 19, 04:45 UTC3h 45m
2026-07-18 ASA647 SEA → STL Jul 18, 20:20 UTCJul 18, 23:40 UTC3h 20m
2026-07-18 ASA47 ANC → SEA Jul 18, 15:10 UTCJul 18, 18:05 UTC2h 55m
2026-07-18 ASA50 - Jul 18, 12:00 UTCJul 18, 13:00 UTC1h 0m
2026-07-18 ASA50 - Jul 18, 07:35 UTCJul 18, 07:50 UTC15m
2026-07-18 ASA50 HNL → ANC Jul 18, 07:43 UTCJul 18, 12:56 UTC5h 13m
2026-07-18 ASA49 SNA → PDX Jul 18, 06:00 UTCJul 18, 06:10 UTC10m
2026-07-18 ASA49 SNA → PDX Jul 18, 00:25 UTCJul 18, 01:15 UTC50m
2026-07-17 ASA83 SEA → ANC Jul 17, 19:45 UTCJul 17, 22:40 UTC2h 55m
2026-07-17 ASA451 - Jul 17, 13:35 UTCJul 17, 18:00 UTC4h 25m
2026-07-17 ASA490 SEA → MSY Jul 17, 07:25 UTCJul 17, 11:35 UTC4h 10m
2026-07-17 ASA1681 LAS → SEA Jul 17, 03:50 UTCJul 17, 05:45 UTC1h 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 N943AK page for operator, model, and routing details .

Mode-S AD1857 frequently asked

What is Mode-S code AD1857?
AD1857 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N943AK.
Where is Mode-S AD1857 registered?
Mode-S code AD1857 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 AD1857 broadcasting right now?
Yes. Mode-S AD1857 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AD1857, octal 53214127, decimal 11,343,959.
What flights does AD1857 operate?
Mode-S AD1857 has broadcast 20 distinct callsigns, including ASA50, ASA49, ASA626, ASA581, ASA203.