Apparatus

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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
Broadcasting now · callsign HK5309G · 8,825 ft
Flights observed
184
Distinct callsigns
1
Country
CR
Last broadcast
1h ago

Current position

0AC981 is currently broadcasting. Map zoomed to live position.

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 - 183 2026-07-14

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-14 HK5309G - Jul 14, 15:20 UTCJul 14, 15:30 UTC10m
2026-07-14 HK5309G - Jul 14, 12:25 UTCJul 14, 12:40 UTC15m
2026-07-13 HK5309G - Jul 13, 15:55 UTCJul 13, 16:30 UTC35m
2026-07-13 HK5309G - Jul 13, 14:25 UTCJul 13, 14:55 UTC30m
2026-07-12 HK5309G - Jul 12, 16:55 UTCJul 12, 17:25 UTC30m
2026-07-12 HK5309G - Jul 12, 15:25 UTCJul 12, 15:55 UTC30m
2026-07-11 HK5309G - Jul 11, 17:40 UTCJul 11, 17:50 UTC10m
2026-07-11 HK5309G - Jul 11, 16:30 UTCJul 11, 16:50 UTC20m
2026-07-11 HK5309G - Jul 11, 15:15 UTCJul 11, 15:40 UTC25m
2026-07-11 HK5309G - Jul 11, 13:45 UTCJul 11, 14:05 UTC20m
2026-07-10 HK5309G - Jul 10, 15:25 UTCJul 10, 15:55 UTC30m
2026-07-10 HK5309G - Jul 10, 13:50 UTCJul 10, 14:20 UTC30m
2026-07-09 HK5309G - Jul 9, 18:15 UTCJul 9, 18:40 UTC25m
2026-07-06 HK5309G - Jul 6, 16:25 UTCJul 6, 17:05 UTC40m
2026-07-02 HK5309G - Jul 2, 16:30 UTCJul 2, 16:50 UTC20m
2026-07-02 HK5309G - Jul 2, 15:00 UTCJul 2, 15:35 UTC35m
2026-07-01 HK5309G - Jul 1, 16:05 UTCJul 1, 16:40 UTC35m
2026-06-27 HK5309G - Jun 27, 12:19 UTCJun 27, 12:34 UTC15m
2026-06-26 HK5309G - Jun 26, 18:04 UTCJun 26, 18:24 UTC20m
2026-06-25 HK5309G - Jun 25, 17:49 UTCJun 25, 18:00 UTC10m
2026-06-24 HK5309G - Jun 24, 19:15 UTCJun 24, 19:44 UTC30m
2026-06-24 HK5309G - Jun 24, 17:50 UTCJun 24, 18:05 UTC15m
2026-06-24 HK5309G - Jun 24, 16:09 UTCJun 24, 16:40 UTC30m
2026-06-22 HK5309G - Jun 22, 15:59 UTCJun 22, 16:29 UTC30m
2026-06-20 HK5309G - Jun 20, 18:45 UTCJun 20, 19:04 UTC20m
2026-06-20 HK5309G - Jun 20, 16:05 UTCJun 20, 16:29 UTC25m
2026-06-19 HK5309G - Jun 19, 18:39 UTCJun 19, 19:09 UTC30m
2026-06-19 HK5309G - Jun 19, 17:24 UTCJun 19, 17:59 UTC35m
2026-06-13 HK5309G - Jun 13, 17:50 UTCJun 13, 18:10 UTC20m
2026-06-13 HK5309G - Jun 13, 14:45 UTCJun 13, 15:15 UTC30m
2026-06-13 HK5309G - Jun 13, 13:30 UTCJun 13, 13:55 UTC25m
2026-06-13 HK5309G - Jun 13, 12:05 UTCJun 13, 12:25 UTC20m
2026-06-11 HK5309G - Jun 11, 20:10 UTCJun 11, 20:40 UTC30m
2026-06-11 HK5309G - Jun 11, 18:45 UTCJun 11, 19:15 UTC30m
2026-06-10 HK5309G - Jun 10, 20:30 UTCJun 10, 20:50 UTC20m
2026-06-10 HK5309G - Jun 10, 19:00 UTCJun 10, 19:30 UTC30m
2026-06-10 HK5309G - Jun 10, 17:55 UTCJun 10, 18:10 UTC15m
2026-06-10 HK5309G - Jun 10, 16:35 UTCJun 10, 16:55 UTC20m
2026-06-10 HK5309G - Jun 10, 15:00 UTCJun 10, 15:35 UTC35m
2026-06-10 HK5309G - Jun 10, 13:30 UTCJun 10, 14:00 UTC30m
2026-06-09 HK5309G - Jun 9, 19:30 UTCJun 9, 20:25 UTC55m
2026-06-09 HK5309G - Jun 9, 18:05 UTCJun 9, 18:35 UTC30m
2026-06-09 HK5309G - Jun 9, 14:30 UTCJun 9, 14:55 UTC25m
2026-06-08 HK5309G - Jun 8, 14:35 UTCJun 8, 14:55 UTC20m
2026-06-08 HK5309G - Jun 8, 13:25 UTCJun 8, 13:50 UTC25m
2026-06-07 HK5309G - Jun 7, 19:05 UTCJun 7, 19:35 UTC30m
2026-06-07 HK5309G - Jun 7, 17:15 UTCJun 7, 17:45 UTC30m
2026-06-07 HK5309G - Jun 7, 15:40 UTCJun 7, 16:10 UTC30m
2026-06-07 HK5309G - Jun 7, 14:25 UTCJun 7, 14:55 UTC30m
2026-06-07 HK5309G - Jun 7, 12:45 UTCJun 7, 13:15 UTC30m

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?
Yes. Mode-S 0AC981 is currently airborne.
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.