Apparatus

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sensors Mode-S transponder

A09905

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N138BC · PIPER PA-28-140/150/160/180 · operated by UNIVERSIDAD INTERAMERICANA DE PUERTO RICO, SCHOOL OF AERONAUTICS

Hex
A09905
Octal
50114405
Decimal
10,524,933
Country
US
Tail
N138BC
Type
P28A
No current signal · last broadcast Jul 23, 13:55 UTC
Flights observed
132
Distinct callsigns
1
Country
US
Last broadcast
Jul 23, 13:55 UTC

Last known position

Most recent position reported by Mode-S A09905.

Country allocation

The ICAO 24-bit address A09905 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
N138BC - 132 2026-07-23

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-23 N138BC - Jul 23, 13:40 UTCJul 23, 13:55 UTC15m
2026-07-23 N138BC SIG → SIG Jul 23, 00:10 UTCJul 23, 01:25 UTC1h 15m
2026-07-22 N138BC - Jul 22, 22:00 UTCJul 22, 23:00 UTC1h 0m
2026-07-22 N138BC - Jul 22, 20:20 UTCJul 22, 20:55 UTC35m
2026-07-22 N138BC - Jul 22, 15:50 UTCJul 22, 16:50 UTC1h 0m
2026-07-22 N138BC - Jul 22, 14:50 UTCJul 22, 15:20 UTC30m
2026-07-22 N138BC SIG → SIG Jul 22, 11:10 UTCJul 22, 12:15 UTC1h 5m
2026-07-21 N138BC - Jul 21, 23:55 UTCJul 22, 01:15 UTC1h 20m
2026-07-21 N138BC - Jul 21, 21:50 UTCJul 21, 23:05 UTC1h 15m
2026-07-21 N138BC - Jul 21, 20:05 UTCJul 21, 21:00 UTC55m
2026-07-21 N138BC - Jul 21, 17:55 UTCJul 21, 19:00 UTC1h 5m
2026-07-21 N138BC SIG → SIG Jul 21, 12:55 UTCJul 21, 14:00 UTC1h 5m
2026-07-21 N138BC SIG → SIG Jul 21, 10:40 UTCJul 21, 11:10 UTC30m
2026-07-20 N138BC - Jul 20, 22:45 UTCJul 20, 23:00 UTC15m
2026-07-20 N138BC - Jul 20, 22:00 UTCJul 20, 22:10 UTC10m
2026-07-20 N138BC - Jul 20, 20:50 UTCJul 20, 21:05 UTC15m
2026-07-20 N138BC - Jul 20, 18:55 UTCJul 20, 19:05 UTC10m
2026-07-20 N138BC - Jul 20, 16:05 UTCJul 20, 16:15 UTC10m
2026-07-20 N138BC - Jul 20, 14:30 UTCJul 20, 14:40 UTC10m
2026-07-20 N138BC SIG → SIG Jul 20, 10:50 UTCJul 20, 11:50 UTC1h 0m
2026-07-17 N138BC - Jul 17, 17:05 UTCJul 17, 18:05 UTC1h 0m
2026-07-17 N138BC - Jul 17, 11:55 UTCJul 17, 12:10 UTC15m
2026-07-17 N138BC - Jul 17, 11:00 UTCJul 17, 11:20 UTC20m
2026-07-16 N138BC - Jul 16, 22:05 UTCJul 16, 22:49 UTC45m
2026-07-16 N138BC - Jul 16, 00:10 UTCJul 16, 01:10 UTC1h 0m
2026-07-15 N138BC SIG → SIG Jul 15, 22:05 UTCJul 15, 23:00 UTC55m
2026-07-15 N138BC - Jul 15, 20:15 UTCJul 15, 20:25 UTC10m
2026-07-15 N138BC - Jul 15, 15:20 UTCJul 15, 15:35 UTC15m
2026-07-15 N138BC - Jul 15, 12:45 UTCJul 15, 14:10 UTC1h 25m
2026-07-15 N138BC - Jul 15, 11:00 UTCJul 15, 11:55 UTC55m
2026-07-07 N138BC SIG → SIG Jul 7, 15:05 UTCJul 7, 16:15 UTC1h 10m
2026-07-07 N138BC - Jul 7, 12:00 UTCJul 7, 12:10 UTC10m
2026-07-06 N138BC - Jul 6, 22:50 UTCJul 6, 23:10 UTC20m
2026-07-06 N138BC - Jul 6, 21:35 UTCJul 6, 21:50 UTC15m
2026-07-06 N138BC - Jul 6, 18:55 UTCJul 6, 19:05 UTC10m
2026-07-06 N138BC - Jul 6, 17:55 UTCJul 6, 18:15 UTC20m
2026-07-06 N138BC - Jul 6, 15:35 UTCJul 6, 16:05 UTC30m
2026-07-06 N138BC - Jul 6, 14:40 UTCJul 6, 15:00 UTC20m
2026-07-06 N138BC SIG → SIG Jul 6, 12:45 UTCJul 6, 13:25 UTC40m
2026-06-22 N138BC - Jun 22, 20:04 UTCJun 22, 20:30 UTC25m
2026-06-22 N138BC - Jun 22, 18:24 UTCJun 22, 18:35 UTC10m
2026-06-22 N138BC - Jun 22, 11:44 UTCJun 22, 11:54 UTC10m
2026-06-22 N138BC - Jun 22, 10:44 UTCJun 22, 10:55 UTC10m
2026-06-20 N138BC - Jun 20, 13:29 UTCJun 20, 14:05 UTC35m
2026-06-20 N138BC - Jun 20, 10:59 UTCJun 20, 11:40 UTC40m
2026-06-18 N138BC SIG → SIG Jun 18, 22:00 UTCJun 18, 22:50 UTC50m
2026-06-18 N138BC - Jun 18, 17:50 UTCJun 18, 18:50 UTC1h 0m
2026-06-18 N138BC - Jun 18, 16:15 UTCJun 18, 16:25 UTC10m
2026-06-18 N138BC SIG → SIG Jun 18, 10:45 UTCJun 18, 11:40 UTC55m
2026-06-17 N138BC - Jun 17, 22:55 UTCJun 17, 23:05 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 N138BC page for operator, model, and routing details .

Mode-S A09905 frequently asked

What is Mode-S code A09905?
A09905 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N138BC.
Where is Mode-S A09905 registered?
Mode-S code A09905 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 A09905 broadcasting right now?
No active broadcast right now. Last signal was Jul 23, 13:55 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A09905, octal 50114405, decimal 10,524,933.
What flights does A09905 operate?
Mode-S A09905 has broadcast 1 distinct callsign, including N138BC.