Apparatus

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sensors Mode-S transponder

A20B5C

ICAO 24-bit transponder address · allocated to United States

Hex
A20B5C
Octal
50405534
Decimal
10,619,740
Country
US
No current signal · last broadcast Jul 9, 07:10 UTC
Flights observed
24
Distinct callsigns
1
Country
US
Last broadcast
Jul 9, 07:10 UTC

Last known position

Most recent position reported by Mode-S A20B5C.

Country allocation

The ICAO 24-bit address A20B5C 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
SERCE32 - 24 2026-07-09

Recent flights last 24

DateFlightRouteTakeoffLandingDuration
2026-07-09 SERCE32 - Jul 9, 06:20 UTCJul 9, 07:10 UTC50m
2026-07-08 SERCE32 - Jul 8, 10:00 UTCJul 8, 10:50 UTC50m
2026-07-08 SERCE32 - Jul 8, 08:05 UTCJul 8, 09:00 UTC55m
2026-07-07 SERCE32 - Jul 7, 07:00 UTCJul 7, 07:40 UTC40m
2026-07-06 SERCE32 - Jul 6, 09:55 UTCJul 6, 10:45 UTC50m
2026-07-06 SERCE32 - Jul 6, 07:00 UTCJul 6, 07:50 UTC50m
2026-07-06 SERCE32 - Jul 6, 05:10 UTCJul 6, 06:05 UTC55m
2026-07-03 SERCE32 - Jul 3, 09:35 UTCJul 3, 10:50 UTC1h 15m
2026-07-03 SERCE32 - Jul 3, 06:20 UTCJul 3, 07:25 UTC1h 5m
2026-07-01 SERCE32 - Jul 1, 09:55 UTCJul 1, 10:45 UTC50m
2026-07-01 SERCE32 - Jul 1, 06:55 UTCJul 1, 07:40 UTC45m
2026-06-30 SERCE32 - Jun 30, 09:55 UTCJun 30, 10:55 UTC1h 0m
2026-06-30 SERCE32 - Jun 30, 08:15 UTCJun 30, 09:10 UTC55m
2026-06-29 SERCE32 - Jun 29, 09:20 UTCJun 29, 10:15 UTC55m
2026-06-29 SERCE32 - Jun 29, 07:44 UTCJun 29, 08:35 UTC50m
2026-06-26 SERCE32 - Jun 26, 07:50 UTCJun 26, 08:05 UTC15m
2026-06-26 SERCE32 - Jun 26, 06:09 UTCJun 26, 07:05 UTC55m
2026-06-25 SERCE32 - Jun 25, 09:29 UTCJun 25, 10:25 UTC55m
2026-06-25 SERCE32 - Jun 25, 07:39 UTCJun 25, 08:34 UTC55m
2026-06-17 SERCE32 - Jun 17, 09:55 UTCJun 17, 10:50 UTC55m
2026-06-17 SERCE32 - Jun 17, 08:00 UTCJun 17, 09:05 UTC1h 5m
2026-06-17 SERCE32 - Jun 17, 06:30 UTCJun 17, 07:15 UTC45m
2026-06-02 SERCE32 - Jun 2, 07:55 UTCJun 2, 08:50 UTC55m
2026-06-02 SERCE32 - Jun 2, 06:10 UTCJun 2, 07:05 UTC55m

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.

Mode-S A20B5C frequently asked

What is Mode-S code A20B5C?
A20B5C is an ICAO 24-bit transponder address. Allocated to United States.
Where is Mode-S A20B5C registered?
Mode-S code A20B5C 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 A20B5C broadcasting right now?
No active broadcast right now. Last signal was Jul 9, 07:10 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A20B5C, octal 50405534, decimal 10,619,740.
What flights does A20B5C operate?
Mode-S A20B5C has broadcast 1 distinct callsign, including SERCE32.