Apparatus

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sensors Mode-S transponder

A4F5A0

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N419AS · BOEING 737-900 · operated by ALASKA AIRLINES INC

Hex
A4F5A0
Octal
51172640
Decimal
10,810,784
Country
US
Tail
N419AS
Type
B739
Broadcasting now · callsign ASA16 · 32,000 ft
Flights observed
452
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 21:25 UTC

Current position

A4F5A0 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A4F5A0 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
ASA616 - 6 2026-06-16
ASA490 - 6 2026-06-22
ASA451 Alaska Airlines 6 2026-06-22
ASA396 Alaska Airlines 6 2026-06-09
ASA1433 - 5 2026-06-29
ASA1331 Alaska Airlines 5 2026-06-16
ASA698 - 4 2026-07-20
ASA67 - 4 2026-07-12
ASA619 Alaska Airlines 4 2026-06-07
ASA459 Alaska Airlines 4 2026-06-11
ASA455 - 4 2026-07-02
ASA421 - 4 2026-06-22
ASA412 Alaska Airlines 4 2026-05-06
ASA35 Alaska Airlines 4 2026-07-07
ASA301 Alaska Airlines 4 2026-06-09
ASA222 - 4 2026-07-08
ASA1411 Alaska Airlines 4 2026-04-28
ASA106 Alaska Airlines 4 2026-04-17
ASA761 - 3 2026-06-24
ASA746 - 3 2026-07-11

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 ASA768 SEA → LAS Jul 26, 16:05 UTCJul 26, 21:25 UTC5h 20m
2026-07-26 ASA1351 SJC → SEA Jul 26, 07:20 UTCJul 26, 12:45 UTC5h 25m
2026-07-26 ASA1352 SFO → BOS Jul 26, 00:25 UTCJul 26, 05:55 UTC5h 30m
2026-07-26 ASA1352 SFO → BOS Jul 26, 00:22 UTCJul 26, 06:05 UTC5h 43m
2026-07-25 ASA502 SEA → AUS Jul 25, 19:55 UTCJul 25, 22:15 UTC2h 20m
2026-07-25 ASA502 SEA → AUS Jul 25, 19:54 UTCJul 25, 22:08 UTC2h 14m
2026-07-25 ASA299 EWR → SEA Jul 25, 11:40 UTCJul 25, 17:15 UTC5h 35m
2026-07-25 ASA1631 SFO → EWR Jul 25, 05:05 UTCJul 25, 09:35 UTC4h 30m
2026-07-24 ASA290 PDX → EWR Jul 24, 22:15 UTCJul 25, 03:45 UTC5h 30m
2026-07-24 ASA294 SFO → EWR Jul 24, 15:00 UTCJul 24, 19:25 UTC4h 25m
2026-07-24 ASA650 LAX → SFO Jul 24, 04:35 UTCJul 24, 06:45 UTC2h 10m
2026-07-24 ASA744 SEA → PHX Jul 24, 00:20 UTCJul 24, 03:00 UTC2h 40m
2026-07-23 ASA446 PHL → SEA Jul 23, 20:45 UTCJul 23, 22:35 UTC1h 50m
2026-07-23 ASA446 PHL → SEA Jul 23, 20:38 UTCJul 23, 22:26 UTC1h 48m
2026-07-23 ASA208 SEA → SFO Jul 23, 17:30 UTCJul 23, 19:40 UTC2h 10m
2026-07-23 ASA208 SEA → SFO Jul 23, 17:30 UTCJul 23, 19:35 UTC2h 5m
2026-07-23 ASA344 LAX → IAD Jul 23, 11:25 UTCJul 23, 15:40 UTC4h 15m
2026-07-23 ASA343 EWR → LAX Jul 23, 05:50 UTCJul 23, 09:20 UTC3h 30m
2026-07-23 ASA268 ANC → SEA Jul 23, 00:50 UTCJul 23, 03:50 UTC3h 0m
2026-07-22 ASA657 JFK → SFO Jul 22, 20:05 UTCJul 22, 23:20 UTC3h 15m
2026-07-22 ASA1473 KOA → SEA Jul 22, 16:05 UTCJul 22, 18:15 UTC2h 10m
2026-07-22 ASA1617 DEN → SAN Jul 22, 12:30 UTCJul 22, 14:20 UTC1h 50m
2026-07-22 ASA1619 SAN → DEN Jul 22, 03:15 UTCJul 22, 05:10 UTC1h 55m
2026-07-22 ASA266 SJC → PDX Jul 22, 01:00 UTCJul 22, 01:40 UTC40m
2026-07-21 ASA266 SJC → PDX Jul 21, 20:50 UTCJul 21, 21:00 UTC10m
2026-07-21 ASA693 PDX → SFO Jul 21, 19:20 UTCJul 21, 19:35 UTC15m
2026-07-21 ASA693 PDX → SFO Jul 21, 14:25 UTCJul 21, 15:05 UTC40m
2026-07-21 ASA628 SEA → JFK Jul 21, 06:00 UTCJul 21, 07:45 UTC1h 45m
2026-07-20 ASA698 LAS → SEA Jul 20, 22:42 UTCJul 21, 00:25 UTC1h 43m
2026-07-20 ASA698 LAS → SEA Jul 20, 22:30 UTCJul 21, 00:30 UTC2h 0m
2026-07-20 ASA738 SEA → LAS Jul 20, 18:50 UTCJul 20, 21:00 UTC2h 10m
2026-07-20 ASA512 - Jul 20, 14:30 UTCJul 20, 16:40 UTC2h 10m
2026-07-19 ASA203 SEA → SJC Jul 19, 22:48 UTCJul 20, 03:29 UTC4h 41m
2026-07-19 ASA245 SEA → OGG Jul 19, 15:40 UTCJul 20, 03:45 UTC12h 5m
2026-07-19 ASA461 ANC → FAI Jul 19, 04:15 UTCJul 19, 13:45 UTC9h 30m
2026-07-18 ASA216 - Jul 18, 22:25 UTCJul 19, 03:00 UTC4h 35m
2026-07-18 ASA216 SEA → CLE Jul 18, 17:10 UTCJul 18, 21:00 UTC3h 50m
2026-07-18 ASA625 PHX → SEA Jul 18, 11:30 UTCJul 18, 15:30 UTC4h 0m
2026-07-18 ASA624 SEA → IND Jul 18, 06:20 UTCJul 18, 09:55 UTC3h 35m
2026-07-18 ASA337 - Jul 18, 00:19 UTCJul 18, 04:15 UTC3h 56m
2026-07-18 ASA337 ORD → SEA Jul 18, 00:29 UTCJul 18, 04:00 UTC3h 31m
2026-07-17 ASA429 SEA → ORD Jul 17, 18:15 UTCJul 17, 22:05 UTC3h 50m
2026-07-17 ASA377 ATL → SEA Jul 17, 11:55 UTCJul 17, 16:19 UTC4h 25m
2026-07-16 ASA727 SEA → ATL Jul 16, 23:35 UTCJul 17, 03:59 UTC4h 25m
2026-07-16 ASA676 LAS → SEA Jul 16, 19:50 UTCJul 16, 21:55 UTC2h 5m
2026-07-16 ASA1628 - Jul 16, 16:35 UTCJul 16, 18:25 UTC1h 50m
2026-07-16 ASA649 BUR → PDX Jul 16, 01:35 UTCJul 16, 03:15 UTC1h 40m
2026-07-15 ASA1386 PDX → BUR Jul 15, 22:20 UTCJul 16, 00:25 UTC2h 5m
2026-07-15 ASA235 - Jul 15, 20:00 UTCJul 15, 21:10 UTC1h 10m
2026-07-15 ASA528 SEA → SFO Jul 15, 16:40 UTCJul 15, 18:40 UTC2h 0m

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 N419AS page for operator, model, and routing details .

Mode-S A4F5A0 frequently asked

What is Mode-S code A4F5A0?
A4F5A0 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N419AS.
Where is Mode-S A4F5A0 registered?
Mode-S code A4F5A0 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 A4F5A0 broadcasting right now?
Yes. Mode-S A4F5A0 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A4F5A0, octal 51172640, decimal 10,810,784.
What flights does A4F5A0 operate?
Mode-S A4F5A0 has broadcast 20 distinct callsigns, including ASA616, ASA490, ASA451, ASA396, ASA1433.