Apparatus

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sensors Mode-S transponder

A21438

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N233FX · operated by FLEXJET LLC

Hex
A21438
Octal
50412070
Decimal
10,622,008
Country
US
Tail
N233FX
No current signal · last broadcast 12h ago
Flights observed
103
Distinct callsigns
3
Country
US
Last broadcast
12h ago

Last known position

Most recent position reported by Mode-S A21438.

Country allocation

The ICAO 24-bit address A21438 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 3 distinct

Callsign Airline Flights Last seen
LXJ233 - 94 2026-07-17
N233FX - 7 2026-06-11
EMB88 - 2 2026-04-21

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-17 LXJ233 - Jul 17, 18:50 UTCJul 17, 20:40 UTC1h 50m
2026-07-17 LXJ233 - Jul 17, 15:29 UTCJul 17, 17:25 UTC1h 55m
2026-07-17 LXJ233 - Jul 17, 01:35 UTCJul 17, 02:34 UTC1h 0m
2026-07-16 LXJ233 - Jul 16, 22:15 UTCJul 17, 00:55 UTC2h 40m
2026-07-16 LXJ233 - Jul 16, 20:09 UTCJul 16, 20:29 UTC20m
2026-07-16 LXJ233 - Jul 16, 17:49 UTCJul 16, 18:19 UTC30m
2026-07-16 LXJ233 - Jul 16, 15:10 UTCJul 16, 15:49 UTC40m
2026-07-15 LXJ233 - Jul 15, 22:50 UTCJul 15, 23:15 UTC25m
2026-07-15 LXJ233 - Jul 15, 19:20 UTCJul 15, 20:50 UTC1h 30m
2026-07-15 LXJ233 DAL → APA Jul 15, 15:55 UTCJul 15, 17:35 UTC1h 40m
2026-07-15 LXJ233 APA → DAL Jul 15, 13:20 UTCJul 15, 15:00 UTC1h 40m
2026-07-14 LXJ233 - Jul 14, 21:05 UTCJul 14, 23:35 UTC2h 29m
2026-07-14 LXJ233 - Jul 14, 18:20 UTCJul 14, 19:20 UTC1h 0m
2026-07-14 LXJ233 - Jul 14, 14:05 UTCJul 14, 15:05 UTC1h 0m
2026-07-13 LXJ233 - Jul 13, 14:20 UTCJul 13, 17:00 UTC2h 40m
2026-07-13 LXJ233 - Jul 13, 11:35 UTCJul 13, 13:45 UTC2h 10m
2026-07-12 LXJ233 - Jul 12, 22:00 UTCJul 12, 23:25 UTC1h 25m
2026-07-12 LXJ233 - Jul 12, 19:30 UTCJul 12, 21:10 UTC1h 40m
2026-07-12 LXJ233 - Jul 12, 15:50 UTCJul 12, 16:35 UTC45m
2026-07-12 LXJ233 - Jul 12, 13:05 UTCJul 12, 13:50 UTC45m
2026-07-10 LXJ233 - Jul 10, 21:00 UTCJul 10, 22:00 UTC1h 0m
2026-07-10 LXJ233 - Jul 10, 18:55 UTCJul 10, 19:20 UTC25m
2026-07-10 LXJ233 - Jul 10, 16:30 UTCJul 10, 16:50 UTC20m
2026-07-10 LXJ233 - Jul 10, 13:20 UTCJul 10, 15:00 UTC1h 40m
2026-07-09 LXJ233 - Jul 9, 23:15 UTCJul 9, 23:55 UTC40m
2026-07-09 LXJ233 IAD → MDW Jul 9, 18:20 UTCJul 9, 19:55 UTC1h 35m
2026-07-09 LXJ233 - Jul 9, 16:00 UTCJul 9, 17:25 UTC1h 25m
2026-07-09 LXJ233 - Jul 9, 00:30 UTCJul 9, 00:45 UTC15m
2026-07-05 LXJ233 - Jul 5, 19:15 UTCJul 5, 21:35 UTC2h 20m
2026-07-05 LXJ233 - Jul 5, 16:50 UTCJul 5, 17:10 UTC20m
2026-07-03 LXJ233 - Jul 3, 17:05 UTCJul 3, 17:30 UTC25m
2026-07-03 LXJ233 - Jul 3, 13:00 UTCJul 3, 14:10 UTC1h 10m
2026-07-02 LXJ233 - Jul 2, 23:00 UTCJul 2, 23:40 UTC40m
2026-07-02 LXJ233 - Jul 2, 20:50 UTCJul 2, 21:35 UTC45m
2026-07-02 LXJ233 - Jul 2, 18:35 UTCJul 2, 19:05 UTC30m
2026-07-01 LXJ233 - Jul 1, 22:45 UTCJul 2, 17:25 UTC18h 40m
2026-07-01 LXJ233 - Jul 1, 18:05 UTCJul 2, 17:25 UTC23h 20m
2026-07-01 LXJ233 - Jul 1, 17:45 UTCJul 2, 16:00 UTC22h 15m
2026-07-01 LXJ233 - Jul 1, 13:45 UTCJul 1, 16:35 UTC2h 50m
2026-06-30 LXJ233 - Jun 30, 14:15 UTCJun 30, 15:15 UTC1h 0m
2026-06-26 LXJ233 LEB → HPN Jun 26, 21:04 UTCJun 26, 21:45 UTC40m
2026-06-26 LXJ233 - Jun 26, 18:49 UTCJun 26, 19:14 UTC25m
2026-06-26 LXJ233 - Jun 26, 16:54 UTCJun 26, 17:29 UTC35m
2026-06-26 LXJ233 - Jun 26, 15:34 UTCJun 26, 16:00 UTC25m
2026-06-26 LXJ233 - Jun 26, 14:15 UTCJun 26, 14:44 UTC30m
2026-06-25 LXJ233 - Jun 25, 20:09 UTCJun 25, 20:49 UTC40m
2026-06-25 LXJ233 - Jun 25, 18:00 UTCJun 25, 19:09 UTC1h 10m
2026-06-25 LXJ233 - Jun 25, 16:14 UTCJun 25, 16:55 UTC40m
2026-06-25 LXJ233 - Jun 25, 14:55 UTCJun 25, 15:29 UTC35m
2026-06-25 LXJ233 - Jun 25, 13:09 UTCJun 25, 13:45 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 N233FX page for operator, model, and routing details .

Mode-S A21438 frequently asked

What is Mode-S code A21438?
A21438 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N233FX.
Where is Mode-S A21438 registered?
Mode-S code A21438 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 A21438 broadcasting right now?
No active broadcast right now. Last signal was 12h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A21438, octal 50412070, decimal 10,622,008.
What flights does A21438 operate?
Mode-S A21438 has broadcast 3 distinct callsigns, including LXJ233, N233FX, EMB88.