Apparatus

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sensors Mode-S transponder

A43E5B

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N37252 · BOEING 737-800 · operated by UNITED AIRLINES INC

Hex
A43E5B
Octal
51037133
Decimal
10,763,867
Country
US
Tail
N37252
Type
B738
No current signal · last broadcast Jul 26, 22:45 UTC
Flights observed
441
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 22:45 UTC

Last known position

Most recent position reported by Mode-S A43E5B.

Country allocation

The ICAO 24-bit address A43E5B 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
UAL1029 United Airlines 5 2026-04-23
UAL2745 - 4 2026-07-15
UAL2654 - 4 2026-06-20
UAL265 United Airlines 4 2026-04-22
UAL2459 United Airlines 4 2026-07-26
UAL2382 - 4 2026-07-08
UAL2275 United Airlines 4 2026-07-24
UAL2177 United Airlines 4 2026-04-17
UAL2005 - 4 2026-06-22
UAL1953 - 4 2026-07-11
UAL1710 United Airlines 4 2026-06-13
UAL1481 United Airlines 4 2026-07-03
UAL669 United Airlines 3 2026-06-04
UAL645 United Airlines 3 2026-05-06
UAL551 - 3 2026-06-19
UAL424 - 3 2026-06-24
UAL2742 United Airlines 3 2026-05-06
UAL2637 United Airlines 3 2026-05-17
UAL2617 - 3 2026-07-07
UAL2366 United Airlines 3 2026-07-19

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL1534 EWR → FLL Jul 26, 21:30 UTCJul 26, 22:45 UTC1h 15m
2026-07-26 UAL2167 ORD → CVG Jul 26, 18:00 UTCJul 26, 19:45 UTC1h 45m
2026-07-26 UAL2459 DEN → YYC Jul 26, 14:15 UTCJul 26, 16:00 UTC1h 45m
2026-07-26 UAL1422 SFO → MFR Jul 26, 01:15 UTCJul 26, 02:45 UTC1h 30m
2026-07-26 UAL1422 SFO → MFR Jul 26, 01:15 UTCJul 26, 02:44 UTC1h 29m
2026-07-25 UAL2470 DEN → MCI Jul 25, 21:05 UTCJul 25, 23:15 UTC2h 10m
2026-07-25 UAL245 BZN → EWR Jul 25, 15:15 UTCJul 25, 19:25 UTC4h 10m
2026-07-25 UAL1935 ORD → LGA Jul 25, 10:25 UTCJul 25, 13:00 UTC2h 35m
2026-07-24 UAL2275 SEA → IAD Jul 24, 21:05 UTCJul 25, 00:45 UTC3h 40m
2026-07-24 UAL2459 DEN → YYC Jul 24, 17:40 UTCJul 24, 19:40 UTC2h 0m
2026-07-24 UAL2270 LAS → IAH Jul 24, 12:15 UTCJul 24, 15:50 UTC3h 35m
2026-07-24 UAL680 SAT → DEN Jul 24, 00:50 UTCJul 24, 03:45 UTC2h 55m
2026-07-23 UAL1534 EWR → FLL Jul 23, 20:55 UTCJul 23, 22:40 UTC1h 45m
2026-07-23 UAL2167 ORD → CVG Jul 23, 17:50 UTCJul 23, 19:05 UTC1h 15m
2026-07-23 UAL2493 PDX → DEN Jul 23, 12:35 UTCJul 23, 16:10 UTC3h 35m
2026-07-23 UAL8101 SFO → RNO Jul 23, 00:45 UTCJul 23, 03:40 UTC2h 55m
2026-07-22 UAL1389 CMH → DEN Jul 22, 19:40 UTCJul 22, 22:50 UTC3h 10m
2026-07-22 UAL480 DFW → EWR Jul 22, 15:45 UTCJul 22, 16:45 UTC1h 0m
2026-07-22 UAL480 DFW → EWR Jul 22, 15:56 UTCJul 22, 18:04 UTC2h 8m
2026-07-22 UAL2754 - Jul 22, 12:20 UTCJul 22, 14:20 UTC2h 0m
2026-07-22 UAL1371 SNA → ORD Jul 22, 03:25 UTCJul 22, 05:25 UTC2h 0m
2026-07-21 UAL2644 AUS → IAH Jul 21, 22:35 UTCJul 22, 02:20 UTC3h 45m
2026-07-21 UAL2644 AUS → IAH Jul 21, 21:59 UTCJul 22, 02:13 UTC4h 14m
2026-07-21 UAL1575 MSP → EWR Jul 21, 16:36 UTCJul 21, 20:24 UTC3h 48m
2026-07-21 UAL1575 MSP → EWR Jul 21, 16:50 UTCJul 21, 20:15 UTC3h 25m
2026-07-21 UAL1234 EWR → ORD Jul 21, 12:10 UTCJul 21, 14:00 UTC1h 50m
2026-07-21 UAL778 DEN → BZN Jul 21, 02:10 UTCJul 21, 04:00 UTC1h 50m
2026-07-20 UAL2085 EWR → AUS Jul 20, 21:35 UTCJul 20, 23:55 UTC2h 20m
2026-07-20 UAL2051 SFO → YVR Jul 20, 18:13 UTCJul 20, 19:42 UTC1h 29m
2026-07-20 UAL2051 SFO → YVR Jul 20, 18:05 UTCJul 20, 19:45 UTC1h 40m
2026-07-20 UAL694 SFO → KOA Jul 20, 12:10 UTCJul 20, 15:10 UTC3h 0m
2026-07-20 UAL1179 IND → IAH Jul 20, 03:45 UTCJul 20, 04:10 UTC25m
2026-07-20 UAL1179 IND → IAH Jul 20, 03:44 UTCJul 20, 04:28 UTC44m
2026-07-19 UAL2217 ORD → PIT Jul 19, 22:40 UTCJul 20, 01:15 UTC2h 35m
2026-07-19 UAL2366 SFO → LAS Jul 19, 17:45 UTCJul 19, 20:55 UTC3h 10m
2026-07-19 UAL251 - Jul 19, 14:30 UTCJul 19, 16:15 UTC1h 45m
2026-07-19 UAL251 ABQ → IAH Jul 19, 14:32 UTCJul 19, 16:08 UTC1h 36m
2026-07-19 UAL1381 - Jul 19, 01:45 UTCJul 19, 03:30 UTC1h 45m
2026-07-18 UAL2323 - Jul 18, 23:15 UTCJul 18, 23:55 UTC40m
2026-07-18 UAL1022 DEN → SAT Jul 18, 20:05 UTCJul 18, 21:55 UTC1h 50m
2026-07-18 UAL640 YVR → DEN Jul 18, 15:55 UTCJul 18, 18:38 UTC2h 43m
2026-07-18 UAL640 YVR → DEN Jul 18, 16:15 UTCJul 18, 18:40 UTC2h 25m
2026-07-18 UAL1910 DEN → YVR Jul 18, 03:25 UTCJul 18, 06:00 UTC2h 35m
2026-07-17 UAL1787 PDX → DEN Jul 17, 23:25 UTCJul 18, 01:34 UTC2h 10m
2026-07-17 UAL2455 EWR → ATL Jul 17, 19:49 UTCJul 17, 21:55 UTC2h 5m
2026-07-17 UAL2375 - Jul 17, 16:00 UTCJul 17, 18:05 UTC2h 5m
2026-07-17 UAL2384 - Jul 17, 06:29 UTCJul 17, 07:40 UTC1h 10m
2026-07-17 UAL1267 LAS → SFO Jul 17, 03:30 UTCJul 17, 04:39 UTC1h 10m
2026-07-17 UAL2338 DEN → LAS Jul 17, 00:20 UTCJul 17, 01:55 UTC1h 35m
2026-07-16 UAL302 - Jul 16, 20:09 UTCJul 16, 22:30 UTC2h 20m

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 N37252 page for operator, model, and routing details .

Mode-S A43E5B frequently asked

What is Mode-S code A43E5B?
A43E5B is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N37252.
Where is Mode-S A43E5B registered?
Mode-S code A43E5B 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 A43E5B broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 22:45 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A43E5B, octal 51037133, decimal 10,763,867.
What flights does A43E5B operate?
Mode-S A43E5B has broadcast 20 distinct callsigns, including UAL1029, UAL2745, UAL2654, UAL265, UAL2459.