Apparatus

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sensors Mode-S transponder

7C2521

ICAO 24-bit transponder address · allocated to Australia

Currently assigned to VH-HMB · PIPER PA-44 Seminole · operated by MELBOURNE FLIGHT ACADEMY PTY LTD

Hex
7C2521
Octal
37022441
Decimal
8,135,969
Country
AU
Tail
VH-HMB
Type
PA44
No current signal · last broadcast 4d ago
Flights observed
47
Distinct callsigns
1
Country
AU
Last broadcast
4d ago

Last known position

Most recent position reported by Mode-S 7C2521.

Country allocation

The ICAO 24-bit address 7C2521 falls within the block assigned to Australia (AU) by ICAO Annex 10, Volume III. Every aircraft registered in Australia 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
HMB - 47 2026-07-10

Recent flights last 47

DateFlightRouteTakeoffLandingDuration
2026-07-10 HMB - Jul 10, 04:35 UTCJul 10, 05:45 UTC1h 10m
2026-07-10 HMB - Jul 10, 03:05 UTCJul 10, 03:45 UTC40m
2026-07-08 HMB - Jul 8, 06:05 UTCJul 8, 06:35 UTC30m
2026-07-08 HMB - Jul 8, 04:55 UTCJul 8, 05:25 UTC30m
2026-07-06 HMB - Jul 6, 06:30 UTCJul 6, 07:05 UTC35m
2026-07-06 HMB - Jul 6, 04:45 UTCJul 6, 05:35 UTC50m
2026-07-06 HMB - Jul 6, 00:15 UTCJul 6, 02:35 UTC2h 20m
2026-07-01 HMB MEB → MEB Jul 1, 04:55 UTCJul 1, 06:30 UTC1h 35m
2026-07-01 HMB - Jul 1, 00:25 UTCJul 1, 03:10 UTC2h 45m
2026-06-29 HMB MEB → MEB Jun 29, 03:34 UTCJun 29, 04:39 UTC1h 5m
2026-06-23 HMB - Jun 23, 02:34 UTCJun 23, 03:09 UTC35m
2026-06-23 HMB - Jun 23, 01:10 UTCJun 23, 01:59 UTC50m
2026-06-20 HMB MEB → MEB Jun 20, 01:29 UTCJun 20, 02:29 UTC1h 0m
2026-06-19 HMB - Jun 19, 04:44 UTCJun 19, 05:45 UTC1h 0m
2026-06-17 HMB - Jun 17, 02:10 UTCJun 17, 04:15 UTC2h 5m
2026-06-14 HMB - Jun 14, 04:00 UTCJun 14, 04:30 UTC30m
2026-06-14 HMB - Jun 14, 02:15 UTCJun 14, 03:10 UTC55m
2026-06-09 HMB - Jun 9, 06:45 UTCJun 9, 07:15 UTC30m
2026-06-09 HMB - Jun 9, 04:55 UTCJun 9, 05:25 UTC30m
2026-06-01 HMB - Jun 1, 01:20 UTCJun 1, 02:40 UTC1h 20m
2026-05-29 HMB - May 29, 05:15 UTCMay 29, 06:10 UTC55m
2026-05-29 HMB - May 29, 03:00 UTCMay 29, 03:25 UTC25m
2026-05-29 HMB - May 29, 01:35 UTCMay 29, 02:00 UTC25m
2026-05-22 HMB MEB → MEB May 22, 05:30 UTCMay 22, 06:20 UTC50m
2026-05-21 HMB - May 21, 00:40 UTCMay 21, 00:55 UTC15m
2026-05-06 HMB MEB → MBW May 6, 02:01 UTCMay 6, 03:15 UTC1h 14m
2026-04-30 HMB - Apr 30, 02:00 UTCApr 30, 05:05 UTC3h 5m
2026-04-28 HMB - Apr 28, 03:45 UTCApr 28, 04:55 UTC1h 10m
2026-04-28 HMB - Apr 28, 02:15 UTCApr 28, 03:15 UTC1h 0m
2026-04-25 HMB MEB → MEB Apr 25, 05:30 UTCApr 25, 06:15 UTC45m
2026-04-23 HMB MEB → MEB Apr 23, 06:20 UTCApr 23, 07:15 UTC55m
2026-04-23 HMB - Apr 23, 00:25 UTCApr 23, 02:00 UTC1h 35m
2026-04-22 HMB - Apr 22, 02:05 UTCApr 22, 05:01 UTC2h 55m
2026-04-21 HMB - Apr 21, 02:50 UTCApr 21, 03:25 UTC35m
2026-04-21 HMB - Apr 21, 00:40 UTCApr 21, 01:15 UTC35m
2026-04-20 HMB MEB → MEB Apr 20, 04:30 UTCApr 20, 04:55 UTC25m
2026-04-20 HMB - Apr 20, 00:30 UTCApr 20, 02:05 UTC1h 35m
2026-04-19 HMB - Apr 19, 23:00 UTCApr 20, 00:00 UTC1h 0m
2026-04-19 HMB MEB → MEB Apr 19, 01:30 UTCApr 19, 04:35 UTC3h 5m
2026-04-17 HMB MEB → MEB Apr 17, 06:15 UTCApr 17, 07:15 UTC1h 0m
2026-04-17 HMB - Apr 17, 02:25 UTCApr 17, 02:50 UTC25m
2026-04-17 HMB - Apr 17, 01:25 UTCApr 17, 01:45 UTC20m
2026-04-17 HMB - Apr 17, 00:25 UTCApr 17, 01:04 UTC40m
2026-04-15 HMB - Apr 15, 02:10 UTCApr 15, 02:25 UTC15m
2026-04-15 HMB - Apr 15, 00:30 UTCApr 15, 00:50 UTC20m
2026-04-13 HMB - Apr 13, 00:20 UTCApr 13, 00:30 UTC10m
2026-04-12 HMB MBW → MEB Apr 12, 23:55 UTCApr 13, 00:30 UTC35m

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 VH-HMB page for operator, model, and routing details .

Mode-S 7C2521 frequently asked

What is Mode-S code 7C2521?
7C2521 is an ICAO 24-bit transponder address. Allocated to Australia. Assigned to VH-HMB.
Where is Mode-S 7C2521 registered?
Mode-S code 7C2521 is allocated to Australia (AU). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 7C2521 broadcasting right now?
No active broadcast right now. Last signal was 4d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 7C2521, octal 37022441, decimal 8,135,969.
What flights does 7C2521 operate?
Mode-S 7C2521 has broadcast 1 distinct callsign, including HMB.