Apparatus

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sensors Mode-S transponder

A43EA3

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N37274 · BOEING 737-800 · operated by UNITED AIRLINES INC

Hex
A43EA3
Octal
51037243
Decimal
10,763,939
Country
US
Tail
N37274
Type
B738
No current signal · last broadcast Jul 26, 22:45 UTC
Flights observed
465
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 22:45 UTC

Last known position

Most recent position reported by Mode-S A43EA3.

Country allocation

The ICAO 24-bit address A43EA3 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
UAL2306 - 8 2026-07-15
UAL204 United Airlines 7 2026-05-12
UAL1522 United Airlines 7 2026-07-24
UAL2177 - 6 2026-06-22
UAL1816 United Airlines 6 2026-07-24
UAL2325 United Airlines 5 2026-06-10
UAL2050 United Airlines 5 2026-05-19
UAL1557 United Airlines 5 2026-05-19
UAL2789 - 4 2026-06-26
UAL2724 United Airlines 4 2026-05-31
UAL2672 United Airlines 4 2026-05-19
UAL2660 - 4 2026-07-06
UAL2654 - 4 2026-06-19
UAL2152 United Airlines 4 2026-07-25
UAL1909 United Airlines 4 2026-07-24
UAL1851 - 4 2026-07-17
UAL1811 - 4 2026-07-16
UAL1719 United Airlines 4 2026-05-12
UAL1151 - 4 2026-06-28
UAL1111 - 4 2026-06-19

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL1255 MCI → EWR Jul 26, 20:50 UTCJul 26, 22:45 UTC1h 55m
2026-07-26 UAL295 DEN → GEG Jul 26, 17:30 UTCJul 26, 19:25 UTC1h 55m
2026-07-26 UAL644 LAX → EWR Jul 26, 14:05 UTCJul 26, 15:35 UTC1h 30m
2026-07-26 UAL1565 SFO → PHX Jul 26, 01:20 UTCJul 26, 02:45 UTC1h 25m
2026-07-25 UAL2152 SJD → DEN Jul 25, 21:55 UTCJul 25, 23:15 UTC1h 20m
2026-07-25 UAL2152 SJD → DEN Jul 25, 20:32 UTCJul 25, 23:20 UTC2h 48m
2026-07-25 UAL294 DEN → SJD Jul 25, 16:45 UTCJul 25, 17:40 UTC55m
2026-07-25 UAL294 DEN → SJD Jul 25, 16:20 UTCJul 25, 19:04 UTC2h 44m
2026-07-25 UAL550 DEN → DFW Jul 25, 12:10 UTCJul 25, 14:05 UTC1h 55m
2026-07-25 UAL720 PHL → DEN Jul 25, 02:25 UTCJul 25, 04:25 UTC2h 0m
2026-07-24 UAL453 LAX → SFO Jul 24, 20:25 UTCJul 24, 23:50 UTC3h 25m
2026-07-24 UAL1909 LAS → EWR Jul 24, 16:05 UTCJul 24, 18:45 UTC2h 40m
2026-07-24 UAL1909 LAS → EWR Jul 24, 16:06 UTCJul 24, 18:49 UTC2h 43m
2026-07-24 UAL1522 FLL → EWR Jul 24, 12:05 UTCJul 24, 14:20 UTC2h 15m
2026-07-24 UAL1816 DEN → CLE Jul 24, 01:50 UTCJul 24, 04:10 UTC2h 20m
2026-07-23 UAL475 EWR → MCO Jul 23, 21:30 UTCJul 23, 23:50 UTC2h 20m
2026-07-23 UAL1029 LAX → DEN Jul 23, 17:35 UTCJul 23, 19:50 UTC2h 15m
2026-07-23 UAL2270 LAS → IAH Jul 23, 12:05 UTCJul 23, 15:40 UTC3h 35m
2026-07-23 UAL2270 LAS → IAH Jul 23, 12:12 UTCJul 23, 15:36 UTC3h 24m
2026-07-23 UAL680 SAT → DEN Jul 23, 00:31 UTCJul 23, 03:52 UTC3h 21m
2026-07-23 UAL680 SAT → DEN Jul 23, 00:45 UTCJul 23, 03:55 UTC3h 10m
2026-07-22 UAL1315 EWR → FLL Jul 22, 16:50 UTCJul 22, 18:20 UTC1h 30m
2026-07-22 UAL1264 IAH → LAS Jul 22, 13:00 UTCJul 22, 15:30 UTC2h 30m
2026-07-21 UAL1854 GCM → IAH Jul 21, 18:48 UTCJul 21, 21:16 UTC2h 28m
2026-07-21 UAL1854 GCM → IAH Jul 21, 15:10 UTCJul 21, 21:20 UTC6h 10m
2026-07-21 UAL1935 ORD → LGA Jul 21, 10:42 UTCJul 21, 13:15 UTC2h 33m
2026-07-21 UAL1935 ORD → LGA Jul 21, 10:50 UTCJul 21, 13:20 UTC2h 30m
2026-07-20 UAL2382 IAH → PHL Jul 20, 21:25 UTCJul 21, 01:30 UTC4h 4m
2026-07-20 UAL1799 MIA → EWR Jul 20, 16:25 UTCJul 20, 19:00 UTC2h 35m
2026-07-20 UAL2358 SAN → EWR Jul 20, 12:40 UTCJul 20, 14:40 UTC2h 0m
2026-07-20 UAL465 - Jul 20, 01:20 UTCJul 20, 03:10 UTC1h 50m
2026-07-19 UAL1696 - Jul 19, 21:50 UTCJul 19, 23:55 UTC2h 5m
2026-07-19 UAL2188 DEN → FLL Jul 19, 16:15 UTCJul 19, 20:00 UTC3h 45m
2026-07-19 UAL2446 - Jul 19, 12:10 UTCJul 19, 14:00 UTC1h 50m
2026-07-19 UAL2028 PHX → DEN Jul 19, 03:15 UTCJul 19, 05:00 UTC1h 45m
2026-07-19 UAL2395 EWR → PBI Jul 19, 00:35 UTCJul 19, 02:00 UTC1h 25m
2026-07-18 UAL267T SFO → BOI Jul 18, 22:00 UTCJul 18, 23:10 UTC1h 10m
2026-07-18 UAL267T SFO → BOI Jul 18, 21:52 UTCJul 18, 23:12 UTC1h 20m
2026-07-18 UAL1712 DFW → SFO Jul 18, 17:30 UTCJul 18, 20:25 UTC2h 55m
2026-07-18 UAL539 PHL → SFO Jul 18, 14:25 UTCJul 18, 16:10 UTC1h 45m
2026-07-18 UAL249 YVR → ORD Jul 18, 08:35 UTCJul 18, 12:10 UTC3h 35m
2026-07-18 UAL1580 - Jul 18, 03:15 UTCJul 18, 07:10 UTC3h 55m
2026-07-17 UAL312 - Jul 17, 21:44 UTCJul 18, 00:35 UTC2h 50m
2026-07-17 UAL2342 - Jul 17, 16:55 UTCJul 17, 19:25 UTC2h 30m
2026-07-17 UAL1491 - Jul 17, 13:05 UTCJul 17, 14:10 UTC1h 5m
2026-07-17 UAL1491 MCI → ORD Jul 17, 13:07 UTCJul 17, 13:55 UTC48m
2026-07-17 UAL1851 ORD → MCI Jul 17, 04:06 UTCJul 17, 04:59 UTC53m
2026-07-17 UAL1851 - Jul 17, 04:04 UTCJul 17, 04:59 UTC55m
2026-07-16 UAL1621 - Jul 16, 23:55 UTCJul 17, 02:25 UTC2h 30m
2026-07-16 UAL1811 - Jul 16, 18:15 UTCJul 16, 21:00 UTC2h 45m

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 N37274 page for operator, model, and routing details .

Mode-S A43EA3 frequently asked

What is Mode-S code A43EA3?
A43EA3 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N37274.
Where is Mode-S A43EA3 registered?
Mode-S code A43EA3 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 A43EA3 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 A43EA3, octal 51037243, decimal 10,763,939.
What flights does A43EA3 operate?
Mode-S A43EA3 has broadcast 20 distinct callsigns, including UAL2306, UAL204, UAL1522, UAL2177, UAL1816.