Apparatus

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sensors Mode-S transponder

A5539C

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N442SA · PIPER PA-44 Seminole · operated by G & M AIRCRAFT INC

Hex
A5539C
Octal
51251634
Decimal
10,834,844
Country
US
Tail
N442SA
Type
PA44
No current signal · last broadcast 1h ago
Flights observed
107
Distinct callsigns
1
Country
US
Last broadcast
1h ago

Last known position

Most recent position reported by Mode-S A5539C.

Country allocation

The ICAO 24-bit address A5539C 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
N442SA - 107 2026-07-15

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-15 N442SA BJC → BJC Jul 15, 00:15 UTCJul 15, 02:05 UTC1h 50m
2026-07-14 N442SA BJC → BJC Jul 14, 18:40 UTCJul 14, 20:50 UTC2h 10m
2026-07-13 N442SA BJC → BJC Jul 13, 12:45 UTCJul 13, 14:35 UTC1h 50m
2026-07-12 N442SA BJC → BJC Jul 12, 11:55 UTCJul 12, 14:05 UTC2h 10m
2026-07-10 N442SA BJC → BJC Jul 10, 13:20 UTCJul 10, 14:40 UTC1h 20m
2026-07-08 N442SA - Jul 8, 15:30 UTCJul 8, 19:10 UTC3h 40m
2026-07-08 N442SA BJC → BJC Jul 8, 12:45 UTCJul 8, 14:40 UTC1h 55m
2026-07-07 N442SA - Jul 7, 18:45 UTCJul 7, 19:20 UTC35m
2026-07-07 N442SA - Jul 7, 11:35 UTCJul 7, 11:55 UTC20m
2026-07-06 N442SA - Jul 6, 23:00 UTCJul 6, 23:45 UTC45m
2026-07-06 N442SA GXY → BJC Jul 6, 19:45 UTCJul 6, 20:10 UTC25m
2026-07-06 N442SA - Jul 6, 17:55 UTCJul 6, 19:05 UTC1h 10m
2026-07-06 N442SA BJC → GXY Jul 6, 16:45 UTCJul 6, 17:05 UTC20m
2026-07-05 N442SA BJC → BJC Jul 5, 18:30 UTCJul 5, 20:10 UTC1h 40m
2026-07-05 N442SA BJC → BJC Jul 5, 15:45 UTCJul 5, 17:10 UTC1h 25m
2026-07-04 N442SA BJC → BJC Jul 4, 19:10 UTCJul 4, 20:30 UTC1h 20m
2026-07-03 N442SA BJC → BJC Jul 3, 15:05 UTCJul 3, 17:35 UTC2h 30m
2026-07-02 N442SA BJC → BJC Jul 2, 21:25 UTCJul 2, 22:20 UTC55m
2026-07-02 N442SA BJC → BJC Jul 2, 18:55 UTCJul 2, 19:50 UTC55m
2026-07-02 N442SA BJC → BJC Jul 2, 16:25 UTCJul 2, 18:00 UTC1h 35m
2026-07-02 N442SA BJC → BJC Jul 2, 12:55 UTCJul 2, 14:35 UTC1h 40m
2026-07-02 N442SA BJC → BJC Jul 2, 01:05 UTCJul 2, 02:05 UTC1h 0m
2026-07-01 N442SA BJC → BJC Jul 1, 21:40 UTCJul 2, 00:00 UTC2h 20m
2026-06-30 N442SA - Jun 30, 20:15 UTCJun 30, 21:30 UTC1h 15m
2026-06-30 N442SA - Jun 30, 14:05 UTCJun 30, 15:25 UTC1h 20m
2026-06-27 N442SA - Jun 27, 16:49 UTCJun 27, 17:39 UTC50m
2026-06-27 N442SA - Jun 27, 14:54 UTCJun 27, 15:34 UTC40m
2026-06-23 N442SA - Jun 23, 22:44 UTCJun 23, 23:55 UTC1h 10m
2026-06-23 N442SA - Jun 23, 18:10 UTCJun 23, 19:10 UTC1h 0m
2026-06-23 N442SA - Jun 23, 17:09 UTCJun 23, 17:34 UTC25m
2026-06-23 N442SA - Jun 23, 14:25 UTCJun 23, 15:24 UTC1h 0m
2026-06-22 N442SA BJC → BJC Jun 22, 19:05 UTCJun 22, 21:19 UTC2h 15m
2026-06-22 N442SA BJC → BJC Jun 22, 13:39 UTCJun 22, 15:14 UTC1h 35m
2026-06-16 N442SA BJC → BJC Jun 16, 13:55 UTCJun 16, 17:05 UTC3h 10m
2026-06-15 N442SA - Jun 15, 21:35 UTCJun 15, 22:15 UTC40m
2026-06-15 N442SA - Jun 15, 17:54 UTCJun 15, 18:40 UTC45m
2026-06-15 N442SA BJC → BJC Jun 15, 12:55 UTCJun 15, 14:00 UTC1h 5m
2026-06-14 N442SA BJC → BJC Jun 14, 15:30 UTCJun 14, 17:10 UTC1h 40m
2026-06-13 N442SA BJC → BJC Jun 13, 20:05 UTCJun 13, 22:05 UTC2h 0m
2026-06-13 N442SA BJC → BJC Jun 13, 15:50 UTCJun 13, 19:10 UTC3h 20m
2026-06-10 N442SA BJC → BJC Jun 10, 21:40 UTCJun 10, 23:25 UTC1h 45m
2026-06-10 N442SA BJC → BJC Jun 10, 14:50 UTCJun 10, 16:00 UTC1h 10m
2026-06-09 N442SA BJC → BJC Jun 9, 19:30 UTCJun 9, 21:30 UTC2h 0m
2026-06-08 N442SA - Jun 8, 23:15 UTCJun 9, 00:50 UTC1h 35m
2026-06-08 N442SA - Jun 8, 20:10 UTCJun 8, 22:00 UTC1h 50m
2026-06-08 N442SA BJC → BJC Jun 8, 16:45 UTCJun 8, 16:55 UTC10m
2026-06-08 N442SA BJC → BJC Jun 8, 14:55 UTCJun 8, 16:40 UTC1h 45m
2026-05-28 N442SA BJC → BJC May 28, 15:35 UTCMay 28, 17:45 UTC2h 10m
2026-05-27 N442SA BJC → BJC May 27, 16:50 UTCMay 27, 17:30 UTC40m
2026-05-27 N442SA BJC → BJC May 27, 12:45 UTCMay 27, 14:35 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 N442SA page for operator, model, and routing details .

Mode-S A5539C frequently asked

What is Mode-S code A5539C?
A5539C is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N442SA.
Where is Mode-S A5539C registered?
Mode-S code A5539C 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 A5539C broadcasting right now?
No active broadcast right now. Last signal was 1h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A5539C, octal 51251634, decimal 10,834,844.
What flights does A5539C operate?
Mode-S A5539C has broadcast 1 distinct callsign, including N442SA.