sensors Mode-S transponder

A25CE1

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N251TC · operated by PIPER AIRCRAFT INC

Hex
A25CE1
Octal
50456341
Decimal
10,640,609
Country
US
Tail
N251TC
No current signal · last broadcast 11h ago
Flights observed
8
Distinct callsigns
1
Country
US
Last broadcast
11h ago

Last known position

Most recent position reported by Mode-S A25CE1.

Country allocation

The ICAO 24-bit address A25CE1 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 1 distinct

Callsign Airline Flights Last seen
N251TC - 8 2026-06-03

Recent flights last 8

DateFlightRouteTakeoffLandingDuration
2026-06-03 N251TC CNW → CNW Jun 3, 18:50 UTCJun 3, 19:50 UTC1h 0m
2026-06-03 N251TC CNW → CNW Jun 3, 15:45 UTCJun 3, 16:50 UTC1h 5m
2026-06-03 N251TC - Jun 3, 13:30 UTCJun 3, 14:25 UTC55m
2026-06-02 N251TC - Jun 2, 15:55 UTCJun 2, 16:40 UTC45m
2026-05-29 N251TC - May 29, 18:55 UTCMay 29, 19:40 UTC45m
2026-05-29 N251TC - May 29, 15:40 UTCMay 29, 17:05 UTC1h 25m
2026-05-28 N251TC - May 28, 18:55 UTCMay 28, 20:55 UTC2h 0m
2026-05-14 N251TC - May 14, 14:20 UTCMay 14, 16:10 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 N251TC page for operator, model, and routing details .

Mode-S A25CE1 frequently asked

What is Mode-S code A25CE1?
A25CE1 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N251TC.
Where is Mode-S A25CE1 registered?
Mode-S code A25CE1 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 A25CE1 broadcasting right now?
No active broadcast right now. Last signal was 11h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A25CE1, octal 50456341, decimal 10,640,609.
What flights does A25CE1 operate?
Mode-S A25CE1 has broadcast 1 distinct callsign, including N251TC.