Apparatus

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sensors Mode-S transponder

A258B4

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N250NK · BEECH 200 Super King Air

Hex
A258B4
Octal
50454264
Decimal
10,639,540
Country
US
Tail
N250NK
Type
BE20
No current signal · last broadcast Jul 26, 15:05 UTC
Flights observed
410
Distinct callsigns
1
Country
US
Last broadcast
Jul 26, 15:05 UTC

Last known position

Most recent position reported by Mode-S A258B4.

Country allocation

The ICAO 24-bit address A258B4 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
CSI502 - 409 2026-07-26

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 CSI502 - Jul 26, 14:45 UTCJul 26, 15:05 UTC20m
2026-07-25 CSI502 - Jul 25, 17:50 UTCJul 25, 18:15 UTC25m
2026-07-25 CSI502 - Jul 25, 08:55 UTCJul 25, 09:20 UTC25m
2026-07-24 CSI502 - Jul 24, 21:30 UTCJul 24, 22:35 UTC1h 5m
2026-07-24 CSI502 - Jul 24, 18:45 UTCJul 24, 19:20 UTC35m
2026-07-24 CSI502 - Jul 24, 10:15 UTCJul 24, 11:15 UTC1h 0m
2026-07-24 CSI502 - Jul 24, 08:00 UTCJul 24, 08:20 UTC20m
2026-07-24 CSI502 - Jul 24, 06:40 UTCJul 24, 06:55 UTC15m
2026-07-24 CSI502 - Jul 24, 04:25 UTCJul 24, 04:45 UTC20m
2026-07-24 CSI502 - Jul 24, 02:55 UTCJul 24, 03:25 UTC30m
2026-07-23 CSI502 - Jul 23, 04:45 UTCJul 23, 05:05 UTC20m
2026-07-23 CSI502 - Jul 23, 02:35 UTCJul 23, 02:50 UTC15m
2026-07-22 CSI502 - Jul 22, 17:50 UTCJul 22, 18:35 UTC45m
2026-07-22 CSI502 - Jul 22, 15:40 UTCJul 22, 16:25 UTC45m
2026-07-22 CSI502 - Jul 22, 04:50 UTCJul 22, 05:00 UTC10m
2026-07-21 CSI502 - Jul 21, 06:30 UTCJul 21, 07:25 UTC55m
2026-07-21 CSI502 - Jul 21, 03:30 UTCJul 21, 04:20 UTC50m
2026-07-19 CSI502 - Jul 19, 06:30 UTCJul 19, 06:50 UTC20m
2026-07-19 CSI502 - Jul 19, 03:15 UTCJul 19, 03:50 UTC35m
2026-07-18 CSI502 - Jul 18, 17:00 UTCJul 18, 17:20 UTC20m
2026-07-18 CSI502 - Jul 18, 14:45 UTCJul 18, 15:00 UTC15m
2026-07-18 CSI502 - Jul 18, 10:40 UTCJul 18, 11:00 UTC20m
2026-07-18 CSI502 - Jul 18, 07:10 UTCJul 18, 07:50 UTC40m
2026-07-18 CSI502 - Jul 18, 04:50 UTCJul 18, 05:25 UTC35m
2026-07-17 CSI502 - Jul 17, 21:25 UTCJul 17, 22:10 UTC45m
2026-07-17 CSI502 - Jul 17, 17:40 UTCJul 17, 18:19 UTC40m
2026-07-17 CSI502 - Jul 17, 01:09 UTCJul 17, 02:54 UTC1h 45m
2026-07-16 CSI502 - Jul 16, 22:15 UTCJul 16, 22:45 UTC30m
2026-07-16 CSI502 - Jul 16, 17:45 UTCJul 16, 18:25 UTC40m
2026-07-16 CSI502 - Jul 16, 14:10 UTCJul 16, 16:19 UTC2h 10m
2026-07-16 CSI502 - Jul 16, 05:55 UTCJul 16, 06:10 UTC15m
2026-07-16 CSI502 - Jul 16, 03:35 UTCJul 16, 03:55 UTC20m
2026-07-16 CSI502 - Jul 16, 01:40 UTCJul 16, 02:10 UTC30m
2026-07-15 CSI502 - Jul 15, 15:15 UTCJul 15, 15:40 UTC25m
2026-07-15 CSI502 - Jul 15, 13:20 UTCJul 15, 13:45 UTC25m
2026-07-15 CSI502 - Jul 15, 07:00 UTCJul 15, 08:45 UTC1h 45m
2026-07-15 CSI502 - Jul 15, 04:05 UTCJul 15, 05:15 UTC1h 10m
2026-07-14 CSI502 - Jul 14, 22:50 UTCJul 14, 23:15 UTC25m
2026-07-14 CSI502 - Jul 14, 20:10 UTCJul 14, 21:15 UTC1h 5m
2026-07-14 CSI502 - Jul 14, 15:35 UTCJul 14, 15:55 UTC20m
2026-07-14 CSI502 - Jul 14, 13:35 UTCJul 14, 13:50 UTC15m
2026-07-14 CSI502 - Jul 14, 08:35 UTCJul 14, 09:10 UTC35m
2026-07-14 CSI502 - Jul 14, 04:35 UTCJul 14, 05:15 UTC40m
2026-07-13 CSI502 - Jul 13, 16:20 UTCJul 13, 17:10 UTC50m
2026-07-13 CSI502 - Jul 13, 13:15 UTCJul 13, 14:10 UTC55m
2026-07-13 CSI502 - Jul 13, 08:10 UTCJul 13, 08:40 UTC30m
2026-07-13 CSI502 - Jul 13, 03:40 UTCJul 13, 04:10 UTC30m
2026-07-12 CSI502 - Jul 12, 07:40 UTCJul 12, 08:30 UTC50m
2026-07-12 CSI502 - Jul 12, 05:45 UTCJul 12, 06:25 UTC40m
2026-07-10 CSI502 - Jul 10, 15:25 UTCJul 10, 15:50 UTC25m

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 N250NK page for operator, model, and routing details .

Mode-S A258B4 frequently asked

What is Mode-S code A258B4?
A258B4 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N250NK.
Where is Mode-S A258B4 registered?
Mode-S code A258B4 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 A258B4 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 15:05 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A258B4, octal 50454264, decimal 10,639,540.
What flights does A258B4 operate?
Mode-S A258B4 has broadcast 1 distinct callsign, including CSI502.