sensors Mode-S transponder

A12B2F

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N17456 · operated by UNITED AIRLINES INC

Hex
A12B2F
Octal
50225457
Decimal
10,562,351
Country
US
Tail
N17456
No current signal · last broadcast 2h ago
Flights observed
5
Distinct callsigns
2
Country
US
Last broadcast
2h ago

Last known position

Most recent position reported by Mode-S A12B2F.

Country allocation

The ICAO 24-bit address A12B2F 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 2 distinct

Callsign Airline Flights Last seen
BOE956 - 3 2026-06-04
BOE123 - 1 2026-05-13

Recent flights last 5

DateFlightRouteTakeoffLandingDuration
2026-06-04 BOE956 - Jun 4, 16:15 UTCJun 4, 18:40 UTC2h 25m
2026-05-28 BOE956 - May 28, 19:05 UTCMay 28, 21:10 UTC2h 5m
2026-05-18 BOE956 - May 18, 20:50 UTCMay 19, 00:20 UTC3h 30m
2026-05-14 - RNT → RNT May 14, 03:30 UTCMay 14, 03:35 UTC5m
2026-05-13 BOE123 RNT → RNT May 13, 22:50 UTCMay 13, 23:25 UTC35m

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 N17456 page for operator, model, and routing details .

Mode-S A12B2F frequently asked

What is Mode-S code A12B2F?
A12B2F is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N17456.
Where is Mode-S A12B2F registered?
Mode-S code A12B2F 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 A12B2F broadcasting right now?
No active broadcast right now. Last signal was 2h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A12B2F, octal 50225457, decimal 10,562,351.
What flights does A12B2F operate?
Mode-S A12B2F has broadcast 2 distinct callsigns, including BOE956, BOE123.