Apparatus

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sensors Mode-S transponder

A43EC9

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N37287 · BOEING 737-800 · operated by UNITED AIRLINES INC

Hex
A43EC9
Octal
51037311
Decimal
10,763,977
Country
US
Tail
N37287
Type
B738
Broadcasting now · callsign UAL324 · 34,000 ft
Flights observed
332
Distinct callsigns
20
Country
US
Last broadcast
16m ago

Current position

A43EC9 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A43EC9 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
UAL2479 United Airlines 6 2026-05-21
UAL645 - 4 2026-07-11
UAL2865 United Airlines 4 2026-05-21
UAL2330 United Airlines 4 2026-05-11
UAL1306 United Airlines 4 2026-04-18
UAL763 United Airlines 3 2026-05-25
UAL680 United Airlines 3 2026-05-07
UAL671 - 3 2026-06-19
UAL414 United Airlines 3 2026-05-08
UAL285 United Airlines 3 2026-04-28
UAL2748 United Airlines 3 2026-04-15
UAL2745 - 3 2026-06-16
UAL2383 - 3 2026-06-20
UAL1714 - 3 2026-06-18
UAL1557 United Airlines 3 2026-05-18
UAL794 United Airlines 2 2026-06-06
UAL691 United Airlines 2 2026-05-17
UAL683 - 2 2026-07-11
UAL667 - 2 2026-06-18
UAL640 - 2 2026-07-14

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-14 UAL324 - Jul 14, 20:05 UTCJul 14, 20:15 UTC10m
2026-07-14 UAL640 YVR → DEN Jul 14, 15:55 UTCJul 14, 18:30 UTC2h 35m
2026-07-14 UAL1910 DEN → YVR Jul 14, 03:40 UTCJul 14, 06:00 UTC2h 20m
2026-07-14 UAL2395 - Jul 14, 00:00 UTCJul 14, 01:30 UTC1h 30m
2026-07-13 UAL267 - Jul 13, 21:45 UTCJul 13, 22:50 UTC1h 5m
2026-07-13 UAL795 - Jul 13, 14:30 UTCJul 13, 19:20 UTC4h 50m
2026-07-13 UAL1965 SFO → RDU Jul 13, 07:50 UTCJul 13, 12:45 UTC4h 55m
2026-07-13 UAL2615 LAS → SFO Jul 13, 04:50 UTCJul 13, 05:55 UTC1h 5m
2026-07-13 UAL2615 LAS → SFO Jul 13, 04:36 UTCJul 13, 05:54 UTC1h 18m
2026-07-13 UAL655 DEN → LAS Jul 13, 01:20 UTCJul 13, 02:50 UTC1h 30m
2026-07-12 UAL475 - Jul 12, 21:40 UTCJul 12, 23:55 UTC2h 15m
2026-07-12 UAL1029 DEN → YEG Jul 12, 17:45 UTCJul 12, 19:49 UTC2h 4m
2026-07-12 UAL1029 - Jul 12, 17:40 UTCJul 12, 19:50 UTC2h 10m
2026-07-12 UAL2045 - Jul 12, 11:45 UTCJul 12, 15:25 UTC3h 40m
2026-07-11 UAL1741 - Jul 11, 22:05 UTCJul 12, 01:35 UTC3h 30m
2026-07-11 UAL645 TPA → DEN Jul 11, 17:05 UTCJul 11, 20:15 UTC3h 10m
2026-07-11 UAL645 TPA → DEN Jul 11, 16:59 UTCJul 11, 20:11 UTC3h 12m
2026-07-11 UAL683 IAD → TPA Jul 11, 13:10 UTCJul 11, 14:55 UTC1h 45m
2026-07-10 UAL2275 YYC → IAD Jul 10, 21:05 UTCJul 11, 00:50 UTC3h 45m
2026-07-10 UAL2459 DEN → YYC Jul 10, 17:35 UTCJul 10, 19:30 UTC1h 55m
2026-07-10 UAL1320 - Jul 10, 12:20 UTCJul 10, 15:25 UTC3h 5m
2026-07-10 UAL2350 - Jul 10, 02:55 UTCJul 10, 05:35 UTC2h 40m
2026-07-09 UAL1255 - Jul 9, 23:30 UTCJul 10, 01:25 UTC1h 55m
2026-07-09 UAL295 DEN → GEG Jul 9, 17:30 UTCJul 9, 19:25 UTC1h 55m
2026-07-09 UAL644 DFW → DEN Jul 9, 14:05 UTCJul 9, 15:35 UTC1h 30m
2026-07-09 UAL8165 DEN → DFW Jul 9, 04:35 UTCJul 9, 06:00 UTC1h 25m
2026-07-08 UAL1001 - Jul 8, 20:45 UTCJul 9, 00:10 UTC3h 25m
2026-07-08 UAL2185 DEN → PNS Jul 8, 16:40 UTCJul 8, 19:00 UTC2h 20m
2026-07-08 UAL2648 - Jul 8, 12:10 UTCJul 8, 14:25 UTC2h 15m
2026-07-08 UAL2121 DEN → GRR Jul 8, 00:59 UTCJul 8, 02:49 UTC1h 50m
2026-07-08 UAL2121 - Jul 8, 00:40 UTCJul 8, 02:15 UTC1h 35m
2026-07-07 UAL2821 - Jul 7, 20:10 UTCJul 7, 23:15 UTC3h 5m
2026-07-07 UAL2821 IND → DEN Jul 7, 20:04 UTCJul 7, 23:11 UTC3h 7m
2026-07-07 UAL1522 - Jul 7, 17:00 UTCJul 7, 19:00 UTC2h 0m
2026-07-03 UAL318 RSW → DEN Jul 3, 12:10 UTCJul 3, 15:35 UTC3h 25m
2026-07-02 UAL2348 - Jul 2, 22:20 UTCJul 3, 01:35 UTC3h 15m
2026-07-02 UAL645 TPA → DEN Jul 2, 16:45 UTCJul 2, 19:55 UTC3h 10m
2026-07-02 UAL683 IAD → TPA Jul 2, 13:15 UTCJul 2, 15:10 UTC1h 55m
2026-07-01 UAL1370 TPA → IAD Jul 1, 23:20 UTCJul 2, 01:15 UTC1h 55m
2026-07-01 UAL1370 TPA → IAD Jul 1, 23:23 UTCJul 2, 01:13 UTC1h 50m
2026-07-01 UAL2812 - Jul 1, 19:55 UTCJul 1, 22:05 UTC2h 10m
2026-07-01 UAL2812 IAH → TPA Jul 1, 20:00 UTCJul 1, 22:00 UTC2h 0m
2026-07-01 UAL2135 - Jul 1, 14:25 UTCJul 1, 18:20 UTC3h 55m
2026-06-30 UAL2638 - Jun 30, 22:50 UTCJul 1, 03:05 UTC4h 15m
2026-06-30 UAL2638 IAH → SEA Jun 30, 23:01 UTCJul 1, 03:01 UTC4h 0m
2026-06-30 UAL743 - Jun 30, 17:00 UTCJun 30, 19:40 UTC2h 40m
2026-06-30 UAL604 DEN → SYR Jun 30, 13:00 UTCJun 30, 15:40 UTC2h 40m
2026-06-27 UAL4204 ICT → IAH Jun 27, 00:58 UTCJun 27, 02:00 UTC1h 2m
2026-06-27 UAL4204 - Jun 27, 00:29 UTCJun 27, 00:39 UTC10m
2026-06-21 UAL2166 TPA → SFO Jun 21, 00:25 UTCJun 21, 01:35 UTC1h 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 N37287 page for operator, model, and routing details .

Mode-S A43EC9 frequently asked

What is Mode-S code A43EC9?
A43EC9 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N37287.
Where is Mode-S A43EC9 registered?
Mode-S code A43EC9 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 A43EC9 broadcasting right now?
Yes. Mode-S A43EC9 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A43EC9, octal 51037311, decimal 10,763,977.
What flights does A43EC9 operate?
Mode-S A43EC9 has broadcast 20 distinct callsigns, including UAL2479, UAL645, UAL2865, UAL2330, UAL1306.