sensors Mode-S transponder

0AC981

ICAO 24-bit transponder address · allocated to Costa Rica

Currently assigned to HK-5309-G · PIPER PA-28-140/150/160/180

Hex
0AC981
Octal
02544601
Decimal
706,945
Country
CR
Tail
HK-5309-G
Type
P28A
No current signal · last broadcast 2d ago
Flights observed
111
Distinct callsigns
1
Country
CR
Last broadcast
2d ago

Last known position

Most recent position reported by Mode-S 0AC981.

Country allocation

The ICAO 24-bit address 0AC981 falls within the block assigned to Costa Rica (CR) by ICAO Annex 10, Volume III. Every aircraft registered in Costa Rica 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
HK5309G - 110 2026-05-27

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-05-27 HK5309G - May 27, 15:00 UTCMay 27, 15:25 UTC25m
2026-05-27 HK5309G - May 27, 13:30 UTCMay 27, 14:05 UTC35m
2026-05-27 HK5309G - May 27, 12:15 UTCMay 27, 12:40 UTC25m
2026-05-26 HK5309G - May 26, 20:45 UTCMay 26, 21:09 UTC25m
2026-05-26 HK5309G - May 26, 19:25 UTCMay 26, 19:45 UTC20m
2026-05-26 HK5309G - May 26, 17:39 UTCMay 26, 18:05 UTC25m
2026-05-26 HK5309G - May 26, 16:20 UTCMay 26, 16:40 UTC20m
2026-05-25 HK5309G - May 25, 20:09 UTCMay 25, 20:50 UTC40m
2026-05-25 HK5309G - May 25, 19:15 UTCMay 25, 19:25 UTC10m
2026-05-25 HK5309G - May 25, 17:20 UTCMay 25, 17:50 UTC30m
2026-05-25 HK5309G - May 25, 16:10 UTCMay 25, 16:35 UTC25m
2026-05-25 HK5309G - May 25, 15:10 UTCMay 25, 15:25 UTC15m
2026-05-25 HK5309G - May 25, 13:50 UTCMay 25, 14:15 UTC25m
2026-05-24 HK5309G - May 24, 12:50 UTCMay 24, 13:10 UTC20m
2026-05-23 HK5309G - May 23, 12:30 UTCMay 23, 13:05 UTC35m
2026-05-22 HK5309G - May 22, 13:15 UTCMay 22, 13:35 UTC20m
2026-05-21 HK5309G - May 21, 20:45 UTCMay 21, 21:05 UTC20m
2026-05-21 HK5309G - May 21, 18:55 UTCMay 21, 19:30 UTC35m
2026-05-21 HK5309G - May 21, 17:45 UTCMay 21, 18:20 UTC35m
2026-05-21 HK5309G - May 21, 16:35 UTCMay 21, 17:00 UTC25m
2026-05-21 HK5309G - May 21, 14:00 UTCMay 21, 14:40 UTC40m
2026-05-21 HK5309G - May 21, 12:10 UTCMay 21, 12:30 UTC20m
2026-05-20 HK5309G - May 20, 21:00 UTCMay 20, 21:25 UTC25m
2026-05-20 HK5309G - May 20, 19:15 UTCMay 20, 19:50 UTC35m
2026-05-20 HK5309G - May 20, 17:35 UTCMay 20, 18:05 UTC30m
2026-05-20 HK5309G - May 20, 16:00 UTCMay 20, 16:35 UTC35m
2026-05-20 HK5309G - May 20, 14:40 UTCMay 20, 15:00 UTC20m
2026-05-20 HK5309G - May 20, 13:20 UTCMay 20, 13:50 UTC30m
2026-05-19 HK5309G - May 19, 18:50 UTCMay 19, 19:15 UTC25m
2026-05-19 HK5309G - May 19, 17:45 UTCMay 19, 18:10 UTC25m
2026-05-19 HK5309G - May 19, 15:40 UTCMay 19, 16:15 UTC35m
2026-05-19 HK5309G - May 19, 13:30 UTCMay 19, 13:45 UTC15m
2026-05-18 HK5309G - May 18, 19:35 UTCMay 18, 19:50 UTC15m
2026-05-18 HK5309G - May 18, 12:50 UTCMay 18, 13:25 UTC35m
2026-05-17 HK5309G - May 17, 14:55 UTCMay 17, 15:25 UTC30m
2026-05-17 HK5309G - May 17, 13:05 UTCMay 17, 13:40 UTC35m
2026-05-16 HK5309G - May 16, 19:55 UTCMay 16, 20:10 UTC15m
2026-05-16 HK5309G - May 16, 17:35 UTCMay 16, 18:05 UTC30m
2026-05-16 HK5309G - May 16, 16:15 UTCMay 16, 16:45 UTC30m
2026-05-15 HK5309G - May 15, 16:45 UTCMay 15, 17:20 UTC35m
2026-05-15 HK5309G - May 15, 15:05 UTCMay 15, 15:30 UTC25m
2026-05-13 HK5309G - May 13, 14:15 UTCMay 13, 14:40 UTC25m
2026-05-12 HK5309G - May 12, 20:20 UTCMay 12, 20:50 UTC30m
2026-05-12 HK5309G - May 12, 17:40 UTCMay 12, 18:00 UTC20m
2026-05-12 HK5309G - May 12, 16:20 UTCMay 12, 16:40 UTC20m
2026-05-12 HK5309G - May 12, 15:01 UTCMay 12, 15:25 UTC25m
2026-05-11 HK5309G - May 11, 17:10 UTCMay 11, 17:35 UTC25m
2026-05-11 HK5309G - May 11, 13:15 UTCMay 11, 13:50 UTC35m
2026-05-10 - - May 10, 17:49 UTCMay 10, 18:15 UTC25m
2026-05-09 HK5309G - May 9, 17:30 UTCMay 9, 17:49 UTC20m

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 HK-5309-G page for operator, model, and routing details .

Mode-S 0AC981 frequently asked

What is Mode-S code 0AC981?
0AC981 is an ICAO 24-bit transponder address. Allocated to Costa Rica. Assigned to HK-5309-G.
Where is Mode-S 0AC981 registered?
Mode-S code 0AC981 is allocated to Costa Rica (CR). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 0AC981 broadcasting right now?
No active broadcast right now. Last signal was 2d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 0AC981, octal 02544601, decimal 706,945.
What flights does 0AC981 operate?
Mode-S 0AC981 has broadcast 1 distinct callsign, including HK5309G.