Apparatus

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sensors Mode-S transponder

A4C6B3

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N407AS · BOEING 737-900 · operated by ALASKA AIRLINES INC

Hex
A4C6B3
Octal
51143263
Decimal
10,798,771
Country
US
Tail
N407AS
Type
B739
No current signal · last broadcast 2h ago
Flights observed
361
Distinct callsigns
20
Country
US
Last broadcast
2h ago

Last known position

Most recent position reported by Mode-S A4C6B3.

Country allocation

The ICAO 24-bit address A4C6B3 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
ASA397 - 9 2026-06-17
ASA500 - 6 2026-06-29
ASA396 Alaska Airlines 6 2026-06-17
ASA387 Alaska Airlines 5 2026-06-28
ASA386 Alaska Airlines 4 2026-05-20
ASA294 Alaska Airlines 4 2026-05-17
ASA216 - 4 2026-07-04
ASA1335 Alaska Airlines 4 2026-05-05
ASA714 Alaska Airlines 3 2026-06-05
ASA596 - 3 2026-07-07
ASA508 Alaska Airlines 3 2026-05-27
ASA459 - 3 2026-06-23
ASA398 - 3 2026-07-10
ASA266 Alaska Airlines 3 2026-05-23
ASA265 Alaska Airlines 3 2026-05-07
ASA1394 Alaska Airlines 3 2026-06-09
ASA1350 Alaska Airlines 3 2026-05-22
ASA1302 - 3 2026-07-10
ASA9806 - 2 2026-04-12
ASA765 Alaska Airlines 2 2026-04-17

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-13 ASA59 - Jul 13, 23:25 UTCJul 14, 04:50 UTC5h 25m
2026-07-13 ASA34 SEA → JFK Jul 13, 16:55 UTCJul 13, 21:45 UTC4h 50m
2026-07-13 ASA491 OAK → SEA Jul 13, 13:25 UTCJul 13, 14:45 UTC1h 20m
2026-07-13 ASA706 SEA → OAK Jul 13, 02:05 UTCJul 13, 03:50 UTC1h 45m
2026-07-11 ASA9577 - Jul 11, 18:40 UTCJul 11, 20:50 UTC2h 10m
2026-07-11 ASA369 PDX → SAN Jul 11, 01:10 UTCJul 11, 03:20 UTC2h 10m
2026-07-10 ASA1302 - Jul 10, 22:30 UTCJul 10, 23:45 UTC1h 15m
2026-07-10 ASA655 SEA → SFO Jul 10, 19:15 UTCJul 10, 21:00 UTC1h 45m
2026-07-10 ASA241 - Jul 10, 13:25 UTCJul 10, 17:35 UTC4h 10m
2026-07-10 ASA398 SEA → IAH Jul 10, 07:25 UTCJul 10, 10:46 UTC3h 21m
2026-07-10 ASA398 - Jul 10, 07:10 UTCJul 10, 10:55 UTC3h 45m
2026-07-10 ASA501 - Jul 10, 01:20 UTCJul 10, 04:50 UTC3h 30m
2026-07-09 ASA497 - Jul 9, 21:00 UTCJul 9, 23:55 UTC2h 55m
2026-07-09 ASA275 - Jul 9, 16:15 UTCJul 9, 19:25 UTC3h 10m
2026-07-09 ASA1521 PDX → FAI Jul 9, 05:20 UTCJul 9, 08:50 UTC3h 30m
2026-07-08 ASA1538 STL → PDX Jul 8, 22:45 UTCJul 9, 02:40 UTC3h 55m
2026-07-08 ASA1635 PDX → STL Jul 8, 18:05 UTCJul 8, 21:20 UTC3h 15m
2026-07-08 ASA1629 LAS → PDX Jul 8, 14:05 UTCJul 8, 15:55 UTC1h 50m
2026-07-08 ASA1456 SJC → PDX Jul 8, 00:00 UTCJul 8, 02:05 UTC2h 5m
2026-07-07 ASA596 - Jul 7, 20:30 UTCJul 7, 22:05 UTC1h 35m
2026-07-07 ASA596 KTN → SEA Jul 7, 20:24 UTCJul 7, 22:00 UTC1h 36m
2026-07-07 ASA653 SFO → ZIH Jul 7, 17:25 UTCJul 7, 18:45 UTC1h 20m
2026-07-07 ASA607 TPA → SFO Jul 7, 13:15 UTCJul 7, 15:20 UTC2h 5m
2026-07-06 ASA1332 - Jul 6, 23:45 UTCJul 7, 04:40 UTC4h 55m
2026-07-06 ASA1332 HNL → ONT Jul 6, 23:56 UTCJul 7, 04:36 UTC4h 40m
2026-07-06 ASA270 - Jul 6, 16:20 UTCJul 6, 21:35 UTC5h 15m
2026-07-06 ASA489 SEA → ONT Jul 6, 04:00 UTCJul 6, 06:15 UTC2h 15m
2026-07-05 ASA582 - Jul 5, 22:25 UTCJul 6, 00:30 UTC2h 5m
2026-07-05 ASA582 PSP → SEA Jul 5, 22:19 UTCJul 6, 00:43 UTC2h 24m
2026-07-05 ASA692 PDX → SFO Jul 5, 18:45 UTCJul 5, 21:00 UTC2h 15m
2026-07-05 ASA274 - Jul 5, 12:20 UTCJul 5, 17:00 UTC4h 40m
2026-07-04 ASA216 SEA → CLE Jul 4, 16:55 UTCJul 4, 20:40 UTC3h 45m
2026-07-04 ASA620 - Jul 4, 13:30 UTCJul 4, 15:15 UTC1h 45m
2026-07-04 ASA590 SFO → ORD Jul 4, 04:15 UTCJul 4, 05:55 UTC1h 40m
2026-07-03 ASA313 SEA → DTW Jul 3, 21:45 UTCJul 4, 02:15 UTC4h 30m
2026-07-03 ASA313 SEA → DTW Jul 3, 16:45 UTCJul 3, 20:30 UTC3h 45m
2026-07-03 ASA440 - Jul 3, 11:10 UTCJul 3, 14:55 UTC3h 45m
2026-07-03 ASA307 SEA → MKE Jul 3, 02:00 UTCJul 3, 05:20 UTC3h 20m
2026-07-03 ASA307 SEA → MKE Jul 3, 01:57 UTCJul 3, 05:24 UTC3h 27m
2026-07-02 ASA1464 OAK → SEA Jul 2, 22:45 UTCJul 3, 00:25 UTC1h 40m
2026-07-02 ASA1328 SEA → SFO Jul 2, 18:55 UTCJul 2, 20:30 UTC1h 35m
2026-07-02 ASA299 EWR → SEA Jul 2, 11:35 UTCJul 2, 16:55 UTC5h 20m
2026-07-02 ASA1631 SFO → EWR Jul 2, 04:45 UTCJul 2, 09:30 UTC4h 45m
2026-07-02 ASA1609 ANC → PDX Jul 2, 00:20 UTCJul 2, 03:30 UTC3h 10m
2026-07-01 ASA657 - Jul 1, 19:46 UTCJul 1, 22:57 UTC3h 11m
2026-07-01 ASA657 SEA → ANC Jul 1, 19:40 UTCJul 1, 23:00 UTC3h 20m
2026-07-01 ASA215 AUS → SEA Jul 1, 13:45 UTCJul 1, 17:35 UTC3h 50m
2026-07-01 ASA1370 PDX → AUS Jul 1, 01:20 UTCJul 1, 05:00 UTC3h 40m
2026-06-30 ASA1302 - Jun 30, 22:35 UTCJun 30, 23:55 UTC1h 20m
2026-06-30 ASA1302 SFO → PDX Jun 30, 22:29 UTCJun 30, 23:57 UTC1h 28m

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 N407AS page for operator, model, and routing details .

Mode-S A4C6B3 frequently asked

What is Mode-S code A4C6B3?
A4C6B3 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N407AS.
Where is Mode-S A4C6B3 registered?
Mode-S code A4C6B3 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 A4C6B3 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 A4C6B3, octal 51143263, decimal 10,798,771.
What flights does A4C6B3 operate?
Mode-S A4C6B3 has broadcast 20 distinct callsigns, including ASA397, ASA500, ASA396, ASA387, ASA386.