Apparatus

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sensors Mode-S transponder

A5FEF4

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N486AS · BOEING 737-900 · operated by ALASKA AIRLINES INC

Hex
A5FEF4
Octal
51377364
Decimal
10,878,708
Country
US
Tail
N486AS
Type
B739
No current signal · last broadcast Jul 26, 23:00 UTC
Flights observed
414
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 23:00 UTC

Last known position

Most recent position reported by Mode-S A5FEF4.

Country allocation

The ICAO 24-bit address A5FEF4 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
ASA546 Alaska Airlines 7 2026-07-23
ASA422 Alaska Airlines 6 2026-07-22
ASA216 Alaska Airlines 6 2026-05-07
ASA200 - 6 2026-06-14
ASA719 Alaska Airlines 4 2026-06-07
ASA700 - 4 2026-06-23
ASA657 - 4 2026-06-28
ASA500 - 4 2026-07-15
ASA75 Alaska Airlines 3 2026-06-07
ASA654 Alaska Airlines 3 2026-05-23
ASA595 Alaska Airlines 3 2026-06-03
ASA507 Alaska Airlines 3 2026-05-18
ASA491 Alaska Airlines 3 2026-05-07
ASA351 Alaska Airlines 3 2026-05-18
ASA283 - 3 2026-06-29
ASA260 Alaska Airlines 3 2026-04-18
ASA236 Alaska Airlines 3 2026-07-26
ASA222 Alaska Airlines 3 2026-04-22
ASA218 Alaska Airlines 3 2026-04-15
ASA1776 Alaska Airlines 3 2026-06-04

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 ASA236 SFO → LAS Jul 26, 22:25 UTCJul 26, 23:00 UTC35m
2026-07-26 ASA621 PDX → SFO Jul 26, 19:00 UTCJul 26, 20:05 UTC1h 5m
2026-07-26 ASA485 CHS → SEA Jul 26, 15:20 UTCJul 26, 16:35 UTC1h 15m
2026-07-25 ASA646 PDX → PHX Jul 25, 23:25 UTCJul 26, 02:45 UTC3h 20m
2026-07-25 ASA392 PDX → DFW Jul 25, 18:35 UTCJul 25, 21:55 UTC3h 20m
2026-07-25 ASA511 BNA → PDX Jul 25, 14:40 UTCJul 25, 16:50 UTC2h 10m
2026-07-25 ASA1550 ANC → SEA Jul 25, 07:30 UTCJul 25, 12:50 UTC5h 20m
2026-07-25 ASA46 BET → ANC Jul 25, 04:40 UTCJul 25, 05:25 UTC45m
2026-07-25 ASA45 ANC → BET Jul 25, 02:25 UTCJul 25, 03:15 UTC50m
2026-07-24 ASA1565 PDX → ANC Jul 24, 21:45 UTCJul 25, 00:55 UTC3h 10m
2026-07-24 ASA1467 LAS → PDX Jul 24, 18:25 UTCJul 24, 20:15 UTC1h 50m
2026-07-24 ASA1467 LAS → PDX Jul 24, 18:24 UTCJul 24, 20:07 UTC1h 43m
2026-07-24 ASA627 PDX → LAS Jul 24, 14:57 UTCJul 24, 16:35 UTC1h 38m
2026-07-24 ASA627 PDX → LAS Jul 24, 14:50 UTCJul 24, 16:45 UTC1h 55m
2026-07-24 ASA609 LAX → PDX Jul 24, 09:25 UTCJul 24, 11:00 UTC1h 35m
2026-07-24 ASA609 LAX → PDX Jul 24, 09:21 UTCJul 24, 12:23 UTC3h 2m
2026-07-24 ASA1899 LAX → ANC Jul 24, 02:50 UTCJul 24, 07:40 UTC4h 50m
2026-07-24 ASA1899 LAX → ANC Jul 24, 02:58 UTCJul 24, 07:40 UTC4h 42m
2026-07-23 ASA1406 LAX → ZLO Jul 23, 23:50 UTCJul 24, 01:05 UTC1h 15m
2026-07-23 ASA546 LAX → EWR Jul 23, 19:55 UTCJul 23, 21:00 UTC1h 5m
2026-07-23 ASA546 LAX → EWR Jul 23, 19:56 UTCJul 23, 21:50 UTC1h 54m
2026-07-23 ASA673 LAS → SFO Jul 23, 15:55 UTCJul 23, 18:15 UTC2h 20m
2026-07-23 ASA1342 PVR → SFO Jul 23, 04:00 UTCJul 23, 04:40 UTC40m
2026-07-22 ASA503 LAX → SEA Jul 22, 22:00 UTCJul 23, 01:40 UTC3h 40m
2026-07-22 ASA422 SEA → SFO Jul 22, 20:20 UTCJul 22, 20:25 UTC5m
2026-07-22 ASA422 SEA → SFO Jul 22, 16:30 UTCJul 22, 20:25 UTC3h 55m
2026-07-22 ASA422 SEA → SFO Jul 22, 16:29 UTCJul 22, 20:05 UTC3h 36m
2026-07-22 ASA323 - Jul 22, 13:10 UTCJul 22, 14:25 UTC1h 15m
2026-07-22 ASA598 SFO → ORD Jul 22, 00:25 UTCJul 22, 01:45 UTC1h 20m
2026-07-22 ASA598 SFO → ORD Jul 22, 00:22 UTCJul 22, 01:37 UTC1h 15m
2026-07-21 ASA446 PHL → SEA Jul 21, 21:00 UTCJul 21, 23:00 UTC2h 0m
2026-07-21 ASA208 SEA → JNU Jul 21, 17:44 UTCJul 21, 19:38 UTC1h 54m
2026-07-21 ASA208 - Jul 21, 17:45 UTCJul 21, 19:00 UTC1h 15m
2026-07-21 ASA607 TPA → SFO Jul 21, 13:15 UTCJul 21, 15:10 UTC1h 55m
2026-07-21 ASA1332 SAN → BOI Jul 21, 00:15 UTCJul 21, 05:15 UTC5h 0m
2026-07-20 ASA270 - Jul 20, 21:40 UTCJul 20, 21:55 UTC15m
2026-07-20 ASA270 - Jul 20, 16:25 UTCJul 20, 17:25 UTC1h 0m
2026-07-20 ASA489 SEA → ONT Jul 20, 03:55 UTCJul 20, 06:10 UTC2h 15m
2026-07-19 ASA641 TUS → SEA Jul 19, 21:40 UTCJul 20, 00:15 UTC2h 35m
2026-07-19 ASA648 SEA → TUS Jul 19, 17:40 UTCJul 19, 20:20 UTC2h 40m
2026-07-19 ASA749 NAS → SEA Jul 19, 04:15 UTCJul 19, 06:15 UTC2h 0m
2026-07-19 ASA531 LAX → PDX Jul 19, 01:05 UTCJul 19, 03:00 UTC1h 55m
2026-07-18 ASA1633 SJC → PDX Jul 18, 21:51 UTCJul 18, 22:51 UTC1h 0m
2026-07-18 ASA1633 SJC → PDX Jul 18, 21:40 UTCJul 18, 22:55 UTC1h 15m
2026-07-18 ASA1632 PDX → SJC Jul 18, 19:00 UTCJul 18, 20:30 UTC1h 30m
2026-07-17 ASA1396 SAN → CUN Jul 17, 23:14 UTCJul 18, 02:50 UTC3h 36m
2026-07-17 ASA540 SFO → AUS Jul 17, 17:55 UTCJul 17, 21:39 UTC3h 45m
2026-07-16 ASA1350 BNA → PDX Jul 16, 23:15 UTCJul 17, 03:25 UTC4h 10m
2026-07-16 ASA1345 SEA → BNA Jul 16, 17:45 UTCJul 16, 21:40 UTC3h 55m
2026-07-16 ASA1529 ABQ → SEA Jul 16, 12:09 UTCJul 16, 14:45 UTC2h 35m

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 N486AS page for operator, model, and routing details .

Mode-S A5FEF4 frequently asked

What is Mode-S code A5FEF4?
A5FEF4 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N486AS.
Where is Mode-S A5FEF4 registered?
Mode-S code A5FEF4 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 A5FEF4 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 23:00 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A5FEF4, octal 51377364, decimal 10,878,708.
What flights does A5FEF4 operate?
Mode-S A5FEF4 has broadcast 20 distinct callsigns, including ASA546, ASA422, ASA216, ASA200, ASA719.