Apparatus

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sensors Mode-S transponder

A2C43E

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N278AK · BOEING 737-900 · operated by ALASKA AIRLINES INC

Hex
A2C43E
Octal
50542076
Decimal
10,667,070
Country
US
Tail
N278AK
Type
B739
No current signal · last broadcast 13d ago
Flights observed
361
Distinct callsigns
20
Country
US
Last broadcast
13d ago

Last known position

Most recent position reported by Mode-S A2C43E.

Country allocation

The ICAO 24-bit address A2C43E 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
ASA450 Alaska Airlines 9 2026-06-05
ASA785 - 6 2026-06-28
ASA530 Alaska Airlines 6 2026-06-09
ASA682 Alaska Airlines 5 2026-06-05
ASA472 Alaska Airlines 5 2026-05-21
ASA787 - 4 2026-06-26
ASA67 - 4 2026-06-28
ASA625 - 4 2026-06-17
ASA573 - 4 2026-06-13
ASA568 - 4 2026-06-18
ASA508 Alaska Airlines 4 2026-05-28
ASA410 Alaska Airlines 4 2026-05-08
ASA351 Alaska Airlines 4 2026-06-06
ASA331 Alaska Airlines 4 2026-06-06
ASA1449 Alaska Airlines 4 2026-05-22
ASA122 Alaska Airlines 4 2026-04-18
ASA765 - 3 2026-06-19
ASA740 Alaska Airlines 3 2026-05-02
ASA623 Alaska Airlines 3 2026-06-02
ASA569 - 3 2026-06-18

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-06-30 ASA9420 SEA → OKC Jun 30, 17:35 UTCJun 30, 21:05 UTC3h 30m
2026-06-30 ASA544 PDX → SFO Jun 30, 01:45 UTCJun 30, 04:45 UTC3h 0m
2026-06-30 ASA544 PDX → SFO Jun 30, 01:44 UTCJun 30, 04:34 UTC2h 50m
2026-06-29 ASA659 LAX → SFO Jun 29, 21:19 UTCJun 30, 00:35 UTC3h 15m
2026-06-29 ASA796 SLC → SEA Jun 29, 17:40 UTCJun 29, 19:24 UTC1h 45m
2026-06-29 ASA292 SEA → SLC Jun 29, 14:46 UTCJun 29, 16:09 UTC1h 23m
2026-06-29 ASA292 SEA → SLC Jun 29, 14:34 UTCJun 29, 16:10 UTC1h 35m
2026-06-29 ASA614 - Jun 29, 03:20 UTCJun 29, 05:45 UTC2h 25m
2026-06-28 ASA1300 SEA → LAX Jun 28, 23:25 UTCJun 29, 01:29 UTC2h 5m
2026-06-28 ASA785 BFI → SEA Jun 28, 20:59 UTCJun 28, 21:04 UTC5m
2026-06-28 ASA785 LAS → SEA Jun 28, 18:44 UTCJun 28, 20:54 UTC2h 10m
2026-06-28 ASA785 LAS → SEA Jun 28, 18:40 UTCJun 28, 20:44 UTC2h 4m
2026-06-28 ASA612 SEA → LAS Jun 28, 15:05 UTCJun 28, 17:00 UTC1h 55m
2026-06-28 ASA54 - Jun 28, 09:34 UTCJun 28, 12:35 UTC3h 0m
2026-06-28 ASA54 ANC → SEA Jun 28, 09:34 UTCJun 28, 12:29 UTC2h 55m
2026-06-28 ASA67 - Jun 28, 05:09 UTCJun 28, 06:40 UTC1h 30m
2026-06-28 ASA67 - Jun 28, 03:50 UTCJun 28, 04:05 UTC15m
2026-06-28 ASA67 - Jun 28, 02:20 UTCJun 28, 02:44 UTC25m
2026-06-28 ASA67 - Jun 28, 00:00 UTCJun 28, 01:15 UTC1h 15m
2026-06-27 ASA785 LAS → SEA Jun 27, 18:55 UTCJun 27, 20:50 UTC1h 55m
2026-06-27 ASA785 - Jun 27, 18:35 UTCJun 27, 18:39 UTC5m
2026-06-27 ASA612 SEA → LAS Jun 27, 15:00 UTCJun 27, 16:49 UTC1h 50m
2026-06-26 ASA787 - Jun 26, 22:29 UTCJun 27, 03:55 UTC5h 25m
2026-06-26 ASA787 - Jun 26, 16:09 UTCJun 26, 20:59 UTC4h 50m
2026-06-25 ASA304 SEA → LAX Jun 25, 22:52 UTCJun 26, 04:25 UTC5h 33m
2026-06-25 ASA304 SEA → LAX Jun 25, 22:45 UTCJun 26, 04:30 UTC5h 45m
2026-06-25 ASA306 SEA → BOS Jun 25, 16:05 UTCJun 25, 20:39 UTC4h 35m
2026-06-25 ASA499 SEA → OAK Jun 25, 13:29 UTCJun 25, 14:04 UTC35m
2026-06-25 ASA1457 SEA → PDX Jun 25, 06:05 UTCJun 25, 06:30 UTC25m
2026-06-24 ASA787 - Jun 24, 22:25 UTCJun 25, 03:59 UTC5h 35m
2026-06-24 ASA787 - Jun 24, 15:59 UTCJun 24, 20:24 UTC4h 25m
2026-06-24 ASA495 - Jun 24, 04:24 UTCJun 24, 06:29 UTC2h 5m
2026-06-24 ASA495 LAX → SEA Jun 24, 04:39 UTCJun 24, 06:32 UTC1h 53m
2026-06-24 ASA278 - Jun 24, 00:55 UTCJun 24, 02:49 UTC1h 55m
2026-06-23 ASA1383 BUR → PDX Jun 23, 21:45 UTCJun 23, 23:29 UTC1h 45m
2026-06-23 ASA1384 PDX → BUR Jun 23, 18:29 UTCJun 23, 20:24 UTC1h 55m
2026-06-23 ASA413 PWK → PDX Jun 23, 12:49 UTCJun 23, 16:59 UTC4h 10m
2026-06-23 ASA328 - Jun 23, 07:35 UTCJun 23, 10:49 UTC3h 15m
2026-06-23 ASA550 DFW → SEA Jun 23, 01:59 UTCJun 23, 05:45 UTC3h 45m
2026-06-22 ASA380 SEA → MSP Jun 22, 21:45 UTCJun 23, 00:15 UTC2h 30m
2026-06-22 ASA1394 PDX → SAN Jun 22, 18:04 UTCJun 22, 20:10 UTC2h 5m
2026-06-22 ASA1394 PDX → SAN Jun 22, 18:01 UTCJun 22, 20:06 UTC2h 5m
2026-06-22 ASA511 BNA → PDX Jun 22, 14:23 UTCJun 22, 16:35 UTC2h 12m
2026-06-22 ASA511 BNA → PDX Jun 22, 14:10 UTCJun 22, 16:34 UTC2h 25m
2026-06-22 ASA1550 ANC → PHX Jun 22, 07:19 UTCJun 22, 12:25 UTC5h 5m
2026-06-22 ASA661 PHX → PAE Jun 22, 02:14 UTCJun 22, 05:29 UTC3h 15m
2026-06-22 ASA661 PHX → PAE Jun 22, 02:13 UTCJun 22, 05:27 UTC3h 14m
2026-06-21 ASA618 - Jun 21, 20:45 UTCJun 22, 00:40 UTC3h 55m
2026-06-21 ASA618 - Jun 21, 15:05 UTCJun 21, 19:00 UTC3h 55m
2026-06-21 ASA594 PDX → SFO Jun 21, 04:20 UTCJun 21, 06:29 UTC2h 10m

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 N278AK page for operator, model, and routing details .

Mode-S A2C43E frequently asked

What is Mode-S code A2C43E?
A2C43E is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N278AK.
Where is Mode-S A2C43E registered?
Mode-S code A2C43E 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 A2C43E broadcasting right now?
No active broadcast right now. Last signal was 13d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A2C43E, octal 50542076, decimal 10,667,070.
What flights does A2C43E operate?
Mode-S A2C43E has broadcast 20 distinct callsigns, including ASA450, ASA785, ASA530, ASA682, ASA472.