Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

A43EA2

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N37273 · BOEING 737-800 · operated by UNITED AIRLINES INC

Hex
A43EA2
Octal
51037242
Decimal
10,763,938
Country
US
Tail
N37273
Type
B738
No current signal · last broadcast 1h ago
Flights observed
182
Distinct callsigns
20
Country
US
Last broadcast
1h ago

Last known position

Most recent position reported by Mode-S A43EA2.

Country allocation

The ICAO 24-bit address A43EA2 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
UAL8188 United Airlines 5 2026-04-18
UAL302 United Airlines 4 2026-05-26
UAL211 United Airlines 4 2026-05-05
UAL1819 United Airlines 4 2026-04-14
UAL8100 United Airlines 3 2026-04-15
UAL430 United Airlines 3 2026-05-08
UAL2617 - 3 2026-04-17
UAL2133 - 3 2026-04-13
UAL1883 United Airlines 3 2026-04-15
UAL8279 United Airlines 2 2026-04-30
UAL786 United Airlines 2 2026-05-16
UAL699 United Airlines 2 2026-05-19
UAL686 United Airlines 2 2026-04-17
UAL635 United Airlines 2 2026-05-02
UAL618 United Airlines 2 2026-05-16
UAL598 United Airlines 2 2026-04-15
UAL574 United Airlines 2 2026-05-22
UAL3872 United Airlines 2 2026-04-24
UAL364 United Airlines 2 2026-05-06
UAL352 United Airlines 2 2026-05-18

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-05-29 UAL2338 PSP → SFO May 29, 20:35 UTCMay 29, 23:15 UTC2h 40m
2026-05-29 UAL2368 SFO → DEN May 29, 17:15 UTCMay 29, 19:05 UTC1h 50m
2026-05-29 UAL2270 LAS → IAH May 29, 12:10 UTCMay 29, 15:35 UTC3h 25m
2026-05-29 UAL680 SAT → DEN May 29, 00:30 UTCMay 29, 03:35 UTC3h 5m
2026-05-28 UAL2239 DEN → SFO May 28, 19:35 UTCMay 28, 22:30 UTC2h 55m
2026-05-28 UAL2239 DEN → SFO May 28, 19:45 UTCMay 28, 23:01 UTC3h 16m
2026-05-28 UAL2195 ORD → IAH May 28, 16:30 UTCMay 28, 18:10 UTC1h 40m
2026-05-28 UAL763 DEN → ORD May 28, 13:30 UTCMay 28, 14:35 UTC1h 5m
2026-05-28 UAL436 SFO → BWI May 28, 06:30 UTCMay 28, 11:00 UTC4h 30m
2026-05-28 UAL1195 DTW → ORD May 28, 03:50 UTCMay 28, 04:50 UTC1h 0m
2026-05-27 UAL741 LAS → EWR May 27, 20:05 UTCMay 28, 02:05 UTC6h 0m
2026-05-27 UAL2487 RSW → EWR May 27, 17:20 UTCMay 27, 18:15 UTC55m
2026-05-27 UAL1481 EWR → CLT May 27, 14:15 UTCMay 27, 14:30 UTC15m
2026-05-27 UAL1481 EWR → CLT May 27, 14:18 UTCMay 27, 15:45 UTC1h 27m
2026-05-26 UAL302 DFW → EWR May 26, 20:40 UTCMay 26, 23:14 UTC2h 35m
2026-05-26 UAL302 DFW → EWR May 26, 20:30 UTCMay 26, 23:10 UTC2h 40m
2026-05-26 UAL1915 SAN → SFO May 26, 16:15 UTCMay 26, 18:34 UTC2h 20m
2026-05-26 UAL550 DEN → DFW May 26, 12:10 UTCMay 26, 14:20 UTC2h 10m
2026-05-26 UAL8156 SFO → YVR May 26, 01:30 UTCMay 26, 04:30 UTC3h 0m
2026-05-25 UAL2821 HNL → EWR May 25, 21:15 UTCMay 25, 23:14 UTC2h 0m
2026-05-25 UAL2011 EWR → SNA May 25, 16:25 UTCMay 25, 19:25 UTC3h 0m
2026-05-25 UAL2865 DEN → ORD May 25, 13:05 UTCMay 25, 15:05 UTC2h 0m
2026-05-25 UAL2479 ORD → LAS May 25, 02:00 UTCMay 25, 03:40 UTC1h 40m
2026-05-24 UAL1943 ORD → CHS May 24, 23:00 UTCMay 24, 23:46 UTC46m
2026-05-24 UAL2327 ORD → SFO May 24, 20:00 UTCMay 24, 21:05 UTC1h 5m
2026-05-24 UAL779 BOS → IAH May 24, 16:35 UTCMay 24, 18:20 UTC1h 45m
2026-05-23 UAL1711 SFO → CLE May 23, 22:35 UTCMay 23, 23:05 UTC30m
2026-05-23 UAL473 IAH → SJC May 23, 13:15 UTCMay 23, 19:10 UTC5h 56m
2026-05-23 UAL349 CZM → ORD May 23, 00:45 UTCMay 23, 03:25 UTC2h 39m
2026-05-22 UAL2855 EWR → SFO May 22, 22:25 UTCMay 22, 23:30 UTC1h 5m
2026-05-22 UAL574 LAS → SFO May 22, 19:10 UTCMay 22, 20:20 UTC1h 10m
2026-05-22 UAL2382 IAH → PHL May 22, 16:20 UTCMay 22, 17:35 UTC1h 15m
2026-05-22 UAL643 KOA → SFO May 22, 13:15 UTCMay 22, 14:20 UTC1h 5m
2026-05-22 UAL406 DEN → LGA May 22, 06:55 UTCMay 22, 07:55 UTC1h 0m
2026-05-22 UAL2482 SFO → HNL May 22, 01:25 UTCMay 22, 05:20 UTC3h 55m
2026-05-21 UAL2090 IAH → PHL May 21, 19:25 UTCMay 21, 22:50 UTC3h 25m
2026-05-21 UAL2831 SEA → SFO May 21, 16:20 UTCMay 21, 18:00 UTC1h 40m
2026-05-21 UAL1007 ORD → ALB May 21, 04:15 UTCMay 21, 06:00 UTC1h 45m
2026-05-21 UAL1603 ORD → PHX May 21, 01:15 UTCMay 21, 02:20 UTC1h 5m
2026-05-21 UAL1603 ORD → PHX May 21, 01:16 UTCMay 21, 02:19 UTC1h 3m
2026-05-20 UAL1971 EWR → SAT May 20, 20:10 UTCMay 20, 23:25 UTC3h 15m
2026-05-20 UAL1902 IAH → GUA May 20, 14:05 UTCMay 20, 17:40 UTC3h 35m
2026-05-19 UAL1684 SFO → LIH May 19, 22:00 UTCMay 20, 01:25 UTC3h 25m
2026-05-19 UAL1684 SFO → LIH May 19, 21:56 UTCMay 20, 01:25 UTC3h 29m
2026-05-19 UAL699 BWI → SFO May 19, 15:25 UTCMay 19, 18:05 UTC2h 40m
2026-05-19 UAL699 BWI → SFO May 19, 15:25 UTCMay 19, 17:56 UTC2h 31m
2026-05-18 UAL1384 DEN → TPA May 18, 22:30 UTCMay 19, 01:50 UTC3h 20m
2026-05-18 UAL352 IAD → BOS May 18, 20:30 UTCMay 18, 21:05 UTC35m
2026-05-18 UAL352 IAD → BOS May 18, 20:26 UTCMay 18, 21:01 UTC35m
2026-05-18 UAL1772 EWR → MYR May 18, 18:00 UTCMay 18, 18:35 UTC34m

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 N37273 page for operator, model, and routing details .

Mode-S A43EA2 frequently asked

What is Mode-S code A43EA2?
A43EA2 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N37273.
Where is Mode-S A43EA2 registered?
Mode-S code A43EA2 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 A43EA2 broadcasting right now?
No active broadcast right now. Last signal was 1h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A43EA2, octal 51037242, decimal 10,763,938.
What flights does A43EA2 operate?
Mode-S A43EA2 has broadcast 20 distinct callsigns, including UAL8188, UAL302, UAL211, UAL1819, UAL8100.