Apparatus

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sensors Mode-S transponder

A71109

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N5543A · CESSNA 180 Skywagon · operated by SELF DEFENSE OF NEW ENGLAND LLC DBA, EPIC SEAPLANE ADVENTURES

Hex
A71109
Octal
51610411
Decimal
10,948,873
Country
US
Tail
N5543A
Type
C180
No current signal · last broadcast Jul 22, 17:55 UTC
Flights observed
45
Distinct callsigns
1
Country
US
Last broadcast
Jul 22, 17:55 UTC

Last known position

Most recent position reported by Mode-S A71109.

Country allocation

The ICAO 24-bit address A71109 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
N5543A - 45 2026-07-22

Recent flights last 45

DateFlightRouteTakeoffLandingDuration
2026-07-22 N5543A - Jul 22, 17:35 UTCJul 22, 17:55 UTC20m
2026-07-20 N5543A - Jul 20, 00:05 UTCJul 20, 00:25 UTC20m
2026-07-17 N5543A - Jul 17, 14:04 UTCJul 17, 15:15 UTC1h 10m
2026-07-16 N5543A - Jul 16, 21:55 UTCJul 16, 22:55 UTC1h 0m
2026-07-15 N5543A - Jul 15, 16:30 UTCJul 15, 17:30 UTC1h 0m
2026-07-15 N5543A - Jul 15, 14:00 UTCJul 15, 14:50 UTC50m
2026-07-14 N5543A - Jul 14, 17:15 UTCJul 14, 17:40 UTC25m
2026-07-12 N5543A - Jul 12, 17:15 UTCJul 12, 17:55 UTC40m
2026-07-09 N5543A - Jul 9, 19:45 UTCJul 9, 20:45 UTC1h 0m
2026-07-06 N5543A - Jul 6, 17:25 UTCJul 6, 17:50 UTC25m
2026-07-06 N5543A - Jul 6, 15:35 UTCJul 6, 15:55 UTC20m
2026-07-01 N5543A - Jul 1, 20:45 UTCJul 1, 21:40 UTC55m
2026-06-30 N5543A - Jun 30, 19:40 UTCJun 30, 20:05 UTC25m
2026-06-28 N5543A - Jun 28, 17:55 UTCJun 28, 18:19 UTC25m
2026-06-19 N5543A - Jun 19, 15:29 UTCJun 19, 15:54 UTC25m
2026-06-17 N5543A - Jun 17, 18:10 UTCJun 17, 18:40 UTC30m
2026-06-16 N5543A - Jun 16, 17:49 UTCJun 16, 18:09 UTC20m
2026-06-14 N5543A - Jun 14, 14:55 UTCJun 14, 15:20 UTC25m
2026-06-13 N5543A - Jun 13, 17:35 UTCJun 13, 17:45 UTC10m
2026-06-13 N5543A - Jun 13, 13:35 UTCJun 13, 13:45 UTC10m
2026-06-12 N5543A - Jun 12, 12:25 UTCJun 12, 12:45 UTC20m
2026-06-10 N5543A - Jun 10, 16:10 UTCJun 10, 16:35 UTC25m
2026-06-09 N5543A - Jun 9, 13:35 UTCJun 9, 14:00 UTC25m
2026-06-07 N5543A - Jun 7, 16:35 UTCJun 7, 16:55 UTC20m
2026-06-06 N5543A - Jun 6, 16:55 UTCJun 6, 17:15 UTC20m
2026-06-05 N5543A - Jun 5, 22:05 UTCJun 5, 22:25 UTC20m
2026-06-05 N5543A - Jun 5, 16:50 UTCJun 5, 17:40 UTC50m
2026-06-04 N5543A - Jun 4, 17:20 UTCJun 4, 17:40 UTC20m
2026-05-31 N5543A - May 31, 19:35 UTCMay 31, 19:55 UTC20m
2026-05-29 N5543A - May 29, 16:10 UTCMay 29, 16:25 UTC15m
2026-05-29 N5543A - May 29, 15:45 UTCMay 29, 16:05 UTC20m
2026-05-25 N5543A - May 25, 18:55 UTCMay 25, 19:15 UTC20m
2026-05-21 N5543A - May 21, 21:05 UTCMay 21, 21:25 UTC20m
2026-05-17 N5543A - May 17, 14:55 UTCMay 17, 15:25 UTC30m
2026-05-16 N5543A - May 16, 13:01 UTCMay 16, 13:15 UTC15m
2026-05-15 N5543A - May 15, 20:50 UTCMay 15, 21:10 UTC20m
2026-04-28 N5543A - Apr 28, 21:45 UTCApr 28, 22:10 UTC25m
2026-04-28 N5543A - Apr 28, 13:25 UTCApr 28, 13:45 UTC20m
2026-04-27 N5543A - Apr 27, 23:30 UTCApr 27, 23:50 UTC20m
2026-04-27 N5543A - Apr 27, 19:05 UTCApr 27, 19:25 UTC20m
2026-04-26 N5543A - Apr 26, 22:05 UTCApr 26, 22:25 UTC20m
2026-04-24 N5543A - Apr 24, 18:55 UTCApr 24, 19:30 UTC35m
2026-04-21 N5543A - Apr 21, 20:25 UTCApr 21, 20:50 UTC25m
2026-04-21 N5543A - Apr 21, 12:05 UTCApr 21, 12:25 UTC20m
2026-04-14 N5543A - Apr 14, 15:00 UTCApr 14, 15:10 UTC10m

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 N5543A page for operator, model, and routing details .

Mode-S A71109 frequently asked

What is Mode-S code A71109?
A71109 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N5543A.
Where is Mode-S A71109 registered?
Mode-S code A71109 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 A71109 broadcasting right now?
No active broadcast right now. Last signal was Jul 22, 17:55 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A71109, octal 51610411, decimal 10,948,873.
What flights does A71109 operate?
Mode-S A71109 has broadcast 1 distinct callsign, including N5543A.