Apparatus

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sensors Mode-S transponder

7C7C39

ICAO 24-bit transponder address · allocated to Australia

Currently assigned to VH-YTN · DIAMOND DA-40 Club Star · operated by FLIGHT TRAINING ADELAIDE PTY LTD

Hex
7C7C39
Octal
37076071
Decimal
8,158,265
Country
AU
Tail
VH-YTN
Type
DA40
No current signal · last broadcast 12h ago
Flights observed
8
Distinct callsigns
1
Country
AU
Last broadcast
12h ago

Last known position

Most recent position reported by Mode-S 7C7C39.

Country allocation

The ICAO 24-bit address 7C7C39 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
YTN - 8 2026-04-14

Recent flights last 8

DateFlightRouteTakeoffLandingDuration
2026-04-14 YTN - Apr 14, 09:55 UTCApr 14, 10:20 UTC25m
2026-04-14 YTN - Apr 14, 07:10 UTCApr 14, 07:45 UTC35m
2026-04-14 YTN - Apr 14, 06:45 UTCApr 14, 07:10 UTC25m
2026-04-14 YTN - Apr 14, 05:15 UTCApr 14, 05:35 UTC20m
2026-04-13 YTN - Apr 13, 23:00 UTCApr 13, 23:20 UTC20m
2026-04-13 YTN - Apr 13, 05:20 UTCApr 13, 08:00 UTC2h 40m
2026-04-13 YTN - Apr 13, 00:20 UTCApr 13, 00:35 UTC15m
2026-04-12 YTN - Apr 12, 23:55 UTCApr 13, 00:35 UTC40m

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-YTN page for operator, model, and routing details .

Mode-S 7C7C39 frequently asked

What is Mode-S code 7C7C39?
7C7C39 is an ICAO 24-bit transponder address. Allocated to Australia. Assigned to VH-YTN.
Where is Mode-S 7C7C39 registered?
Mode-S code 7C7C39 is allocated to Australia (AU). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 7C7C39 broadcasting right now?
No active broadcast right now. Last signal was 12h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 7C7C39, octal 37076071, decimal 8,158,265.
What flights does 7C7C39 operate?
Mode-S 7C7C39 has broadcast 1 distinct callsign, including YTN.