sensors Mode-S transponder

A43EA7

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N37278 · BOEING 737 MAX 8 · operated by UNITED AIRLINES INC

Hex
A43EA7
Octal
51037247
Decimal
10,763,943
Country
US
Tail
N37278
Type
B38M
No current signal · last broadcast 1d ago
Flights observed
6
Distinct callsigns
4
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S A43EA7.

Country allocation

The ICAO 24-bit address A43EA7 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 4 distinct

Callsign Airline Flights Last seen
UAL1111 - 3 2026-04-13
UAL2866 United Airlines 1 2026-04-14
UAL2619 - 1 2026-04-12
UAL1750 - 1 2026-04-13

Recent flights last 6

DateFlightRouteTakeoffLandingDuration
2026-04-14 UAL2866 LAX → CLE Apr 14, 06:20 UTCApr 14, 07:05 UTC45m
2026-04-13 UAL1111 - Apr 13, 20:55 UTCApr 13, 23:20 UTC2h 25m
2026-04-13 UAL1111 - Apr 13, 16:15 UTCApr 13, 16:35 UTC20m
2026-04-13 UAL1111 - Apr 13, 15:50 UTCApr 13, 21:21 UTC5h 31m
2026-04-13 UAL1750 - Apr 13, 13:00 UTCApr 13, 13:30 UTC30m
2026-04-12 UAL2619 PHX → SFO Apr 12, 17:45 UTCApr 12, 19:35 UTC1h 50m

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 N37278 page for operator, model, and routing details .

Mode-S A43EA7 frequently asked

What is Mode-S code A43EA7?
A43EA7 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N37278.
Where is Mode-S A43EA7 registered?
Mode-S code A43EA7 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 A43EA7 broadcasting right now?
No active broadcast right now. Last signal was 1d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A43EA7, octal 51037247, decimal 10,763,943.
What flights does A43EA7 operate?
Mode-S A43EA7 has broadcast 4 distinct callsigns, including UAL1111, UAL2866, UAL2619, UAL1750.