sensors Mode-S transponder

A12AEB

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N17438 · BOEING 737 MAX 9 · operated by UNITED AIRLINES INC

Hex
A12AEB
Octal
50225353
Decimal
10,562,283
Country
US
Tail
N17438
Type
B39M
No current signal · last broadcast 23h ago
Flights observed
8
Distinct callsigns
5
Country
US
Last broadcast
23h ago

Last known position

Most recent position reported by Mode-S A12AEB.

Country allocation

The ICAO 24-bit address A12AEB 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 5 distinct

Callsign Airline Flights Last seen
UAL588 - 2 2026-04-13
UAL1134 - 2 2026-04-12
UAL1066 - 2 2026-04-13
UAL1781 United Airlines 1 2026-04-13
UAL1311 United Airlines 1 2026-04-13

Recent flights last 8

DateFlightRouteTakeoffLandingDuration
2026-04-13 UAL1781 EWR → CHS Apr 13, 22:35 UTCApr 14, 00:17 UTC1h 42m
2026-04-13 UAL1311 EWR → CLT Apr 13, 19:55 UTCApr 13, 21:05 UTC1h 10m
2026-04-13 UAL1066 - Apr 13, 04:18 UTCApr 13, 06:15 UTC1h 57m
2026-04-13 UAL1066 - Apr 13, 04:20 UTCApr 13, 06:15 UTC1h 55m
2026-04-13 UAL588 - Apr 13, 00:20 UTCApr 13, 01:35 UTC1h 15m
2026-04-12 UAL588 - Apr 12, 23:55 UTCApr 13, 01:35 UTC1h 40m
2026-04-12 UAL1134 - Apr 12, 15:58 UTCApr 12, 18:00 UTC2h 2m
2026-04-12 UAL1134 - Apr 12, 17:15 UTCApr 12, 17:55 UTC40m

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 N17438 page for operator, model, and routing details .

Mode-S A12AEB frequently asked

What is Mode-S code A12AEB?
A12AEB is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N17438.
Where is Mode-S A12AEB registered?
Mode-S code A12AEB 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 A12AEB broadcasting right now?
No active broadcast right now. Last signal was 23h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A12AEB, octal 50225353, decimal 10,562,283.
What flights does A12AEB operate?
Mode-S A12AEB has broadcast 5 distinct callsigns, including UAL588, UAL1134, UAL1066, UAL1781, UAL1311.