Apparatus

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sensors Mode-S transponder

A61B4E

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N493AS · BOEING 737-900 · operated by ALASKA AIRLINES INC

Hex
A61B4E
Octal
51415516
Decimal
10,885,966
Country
US
Tail
N493AS
Type
B739
No current signal · last broadcast Jul 26, 15:30 UTC
Flights observed
468
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 15:30 UTC

Last known position

Most recent position reported by Mode-S A61B4E.

Country allocation

The ICAO 24-bit address A61B4E 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
ASA252 Alaska Airlines 8 2026-06-13
ASA253 Alaska Airlines 7 2026-06-13
ASA222 - 7 2026-07-10
ASA205 - 6 2026-07-10
ASA62 - 5 2026-07-12
ASA49 Alaska Airlines 5 2026-07-23
ASA35 Alaska Airlines 5 2026-04-30
ASA1477 Alaska Airlines 5 2026-06-25
ASA731 - 4 2026-07-05
ASA682 - 4 2026-04-16
ASA677 Alaska Airlines 4 2026-04-17
ASA670 - 4 2026-04-17
ASA450 - 4 2026-06-19
ASA42 Alaska Airlines 4 2026-04-14
ASA324 Alaska Airlines 4 2026-06-16
ASA295 - 4 2026-07-13
ASA206 Alaska Airlines 4 2026-06-12
ASA744 - 3 2026-06-16
ASA737 Alaska Airlines 3 2026-05-21
ASA725 Alaska Airlines 3 2026-06-23

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 ASA607 TPA → SFO Jul 26, 13:25 UTCJul 26, 15:25 UTC2h 0m
2026-07-26 ASA607 TPA → SFO Jul 26, 13:32 UTCJul 26, 15:14 UTC1h 42m
2026-07-26 ASA489 MSY → SEA Jul 26, 04:50 UTCJul 26, 07:00 UTC2h 11m
2026-07-25 ASA218 SFO → PDX Jul 25, 21:20 UTCJul 26, 02:05 UTC4h 45m
2026-07-25 ASA784 PDX → ATL Jul 25, 14:55 UTCJul 25, 20:00 UTC5h 5m
2026-07-24 ASA1350 SEA → SFO Jul 24, 22:30 UTCJul 25, 02:50 UTC4h 20m
2026-07-24 ASA1345 SJD → SFO Jul 24, 17:25 UTCJul 24, 21:10 UTC3h 45m
2026-07-24 ASA409 IAD → SEA Jul 24, 10:20 UTCJul 24, 15:40 UTC5h 20m
2026-07-24 ASA406 IAD → SEA Jul 24, 00:35 UTCJul 24, 04:45 UTC4h 10m
2026-07-23 ASA293 EWR → SFO Jul 23, 22:15 UTCJul 23, 23:00 UTC45m
2026-07-23 ASA293 EWR → SFO Jul 23, 22:01 UTCJul 23, 22:55 UTC54m
2026-07-23 ASA449 TPA → SFO Jul 23, 20:05 UTCJul 23, 20:45 UTC40m
2026-07-23 ASA753 PSP → SEA Jul 23, 16:10 UTCJul 23, 18:02 UTC1h 52m
2026-07-23 ASA753 PSP → SEA Jul 23, 15:55 UTCJul 23, 18:15 UTC2h 20m
2026-07-23 ASA1412 SJD → SEA Jul 23, 12:30 UTCJul 23, 13:15 UTC45m
2026-07-23 ASA1412 SJD → SEA Jul 23, 08:25 UTCJul 23, 08:40 UTC15m
2026-07-23 ASA49 SNA → PDX Jul 23, 06:10 UTCJul 23, 06:25 UTC15m
2026-07-23 ASA49 SNA → PDX Jul 23, 00:55 UTCJul 23, 01:35 UTC40m
2026-07-22 ASA44 - Jul 22, 22:20 UTCJul 22, 23:10 UTC50m
2026-07-22 ASA43 - Jul 22, 19:50 UTCJul 22, 20:35 UTC45m
2026-07-22 ASA79 SJC → PVR Jul 22, 15:10 UTCJul 22, 18:30 UTC3h 20m
2026-07-22 ASA79 SJC → PVR Jul 22, 15:09 UTCJul 22, 18:19 UTC3h 10m
2026-07-22 ASA17 JFK → SEA Jul 22, 04:05 UTCJul 22, 05:25 UTC1h 20m
2026-07-21 ASA20 SFO → JFK Jul 21, 23:30 UTCJul 22, 02:10 UTC2h 40m
2026-07-21 ASA20 SFO → JFK Jul 21, 14:45 UTCJul 21, 20:00 UTC5h 15m
2026-07-21 ASA590 SFO → ORD Jul 21, 05:55 UTCJul 21, 07:40 UTC1h 45m
2026-07-21 ASA590 SFO → ORD Jul 21, 04:34 UTCJul 21, 07:37 UTC3h 3m
2026-07-20 ASA313 - Jul 20, 21:35 UTCJul 21, 02:15 UTC4h 40m
2026-07-20 ASA313 SEA → DTW Jul 20, 16:40 UTCJul 20, 20:05 UTC3h 25m
2026-07-20 ASA620 SEA → DEN Jul 20, 13:15 UTCJul 20, 14:45 UTC1h 30m
2026-07-20 ASA590 SFO → ORD Jul 20, 05:30 UTCJul 20, 07:30 UTC2h 0m
2026-07-20 ASA665 PDX → ANC Jul 20, 01:19 UTCJul 20, 02:31 UTC1h 12m
2026-07-20 ASA665 PDX → ANC Jul 20, 01:05 UTCJul 20, 02:45 UTC1h 40m
2026-07-19 ASA368 SEA → SLC Jul 19, 22:15 UTCJul 19, 23:55 UTC1h 40m
2026-07-19 ASA275 FAI → SEA Jul 19, 16:10 UTCJul 19, 19:20 UTC3h 10m
2026-07-19 ASA275 FAI → SEA Jul 19, 16:10 UTCJul 19, 19:07 UTC2h 57m
2026-07-19 ASA1521 SAN → ORD Jul 19, 05:15 UTCJul 19, 08:45 UTC3h 30m
2026-07-19 ASA1521 SAN → ORD Jul 19, 05:15 UTCJul 19, 08:49 UTC3h 34m
2026-07-18 ASA1319 SFO → PDX Jul 18, 21:40 UTCJul 19, 03:30 UTC5h 50m
2026-07-18 ASA390 - Jul 18, 14:30 UTCJul 18, 20:00 UTC5h 30m
2026-07-18 ASA1398 SEA → SAN Jul 18, 04:00 UTCJul 18, 06:25 UTC2h 25m
2026-07-18 ASA1413 GDL → LAX Jul 18, 00:39 UTCJul 18, 02:14 UTC1h 35m
2026-07-17 ASA1366 SEA → SJC Jul 17, 21:34 UTCJul 17, 23:25 UTC1h 50m
2026-07-16 ASA17 JFK → SEA Jul 16, 03:32 UTCJul 16, 08:53 UTC5h 21m
2026-07-16 ASA17 JFK → SEA Jul 16, 03:35 UTCJul 16, 08:55 UTC5h 20m
2026-07-16 ASA18 - Jul 16, 01:35 UTCJul 16, 01:50 UTC15m
2026-07-16 ASA18 - Jul 16, 00:40 UTCJul 16, 01:50 UTC1h 10m
2026-07-15 ASA18 - Jul 15, 18:15 UTCJul 15, 23:10 UTC4h 55m
2026-07-15 ASA1626 DEN → PDX Jul 15, 14:05 UTCJul 15, 16:15 UTC2h 10m
2026-07-15 ASA752 - Jul 15, 07:30 UTCJul 15, 12:20 UTC4h 50m

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 N493AS page for operator, model, and routing details .

Mode-S A61B4E frequently asked

What is Mode-S code A61B4E?
A61B4E is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N493AS.
Where is Mode-S A61B4E registered?
Mode-S code A61B4E 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 A61B4E broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 15:30 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A61B4E, octal 51415516, decimal 10,885,966.
What flights does A61B4E operate?
Mode-S A61B4E has broadcast 20 distinct callsigns, including ASA252, ASA253, ASA222, ASA205, ASA62.