sensors Mode-S transponder

A12AEA

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N17437 · BOEING 737 MAX 9 · operated by UNITED AIRLINES INC

Hex
A12AEA
Octal
50225352
Decimal
10,562,282
Country
US
Tail
N17437
Type
B39M
No current signal · last broadcast 19h ago
Flights observed
9
Distinct callsigns
5
Country
US
Last broadcast
19h ago

Last known position

Most recent position reported by Mode-S A12AEA.

Country allocation

The ICAO 24-bit address A12AEA 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
UAL630 - 3 2026-04-13
UAL2107 United Airlines 3 2026-04-13
UAL2356 United Airlines 1 2026-04-12
UAL1863 - 1 2026-04-13
UAL1007 United Airlines 1 2026-04-14

Recent flights last 9

DateFlightRouteTakeoffLandingDuration
2026-04-14 UAL1007 ORD → ALB Apr 14, 05:15 UTCApr 14, 06:35 UTC1h 20m
2026-04-13 UAL1863 - Apr 13, 21:00 UTCApr 13, 23:40 UTC2h 40m
2026-04-13 UAL630 - Apr 13, 16:15 UTCApr 13, 18:55 UTC2h 40m
2026-04-13 UAL630 - Apr 13, 15:55 UTCApr 13, 18:55 UTC3h 0m
2026-04-13 UAL630 - Apr 13, 14:25 UTCApr 13, 16:15 UTC1h 50m
2026-04-13 UAL2107 ORD → CVG Apr 13, 04:20 UTCApr 13, 07:05 UTC2h 45m
2026-04-13 UAL2107 ORD → CVG Apr 13, 03:55 UTCApr 13, 07:05 UTC3h 10m
2026-04-13 UAL2107 ORD → CVG Apr 13, 00:35 UTCApr 13, 04:10 UTC3h 35m
2026-04-12 UAL2356 BUR → SFO Apr 12, 18:05 UTCApr 12, 20:15 UTC2h 10m

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 N17437 page for operator, model, and routing details .

Mode-S A12AEA frequently asked

What is Mode-S code A12AEA?
A12AEA is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N17437.
Where is Mode-S A12AEA registered?
Mode-S code A12AEA 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 A12AEA broadcasting right now?
No active broadcast right now. Last signal was 19h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A12AEA, octal 50225352, decimal 10,562,282.
What flights does A12AEA operate?
Mode-S A12AEA has broadcast 5 distinct callsigns, including UAL630, UAL2107, UAL2356, UAL1863, UAL1007.