sensors Mode-S transponder

7C42F9

ICAO 24-bit transponder address · allocated to Australia

Currently assigned to VH-NIJ · CESSNA 172 Skyhawk · operated by ROYAL MELBOURNE INSTITUTE OF TECHNOLOGY

Hex
7C42F9
Octal
37041371
Decimal
8,143,609
Country
AU
Tail
VH-NIJ
Type
C172
Broadcasting now · callsign NIJ · -200 ft
Flights observed
5
Distinct callsigns
1
Country
AU
Last broadcast
12h ago

Current position

7C42F9 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address 7C42F9 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
NIJ - 5 2026-04-14

Recent flights last 5

DateFlightRouteTakeoffLandingDuration
2026-04-14 NIJ - Apr 14, 09:50 UTCApr 14, 10:35 UTC45m
2026-04-14 NIJ - Apr 14, 09:10 UTCApr 14, 09:30 UTC20m
2026-04-14 NIJ - Apr 14, 08:50 UTCApr 14, 09:05 UTC15m
2026-04-14 NIJ - Apr 14, 06:15 UTCApr 14, 07:00 UTC45m
2026-04-13 NIJ - Apr 13, 04:25 UTCApr 13, 05:10 UTC45m

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

Mode-S 7C42F9 frequently asked

What is Mode-S code 7C42F9?
7C42F9 is an ICAO 24-bit transponder address. Allocated to Australia. Assigned to VH-NIJ.
Where is Mode-S 7C42F9 registered?
Mode-S code 7C42F9 is allocated to Australia (AU). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 7C42F9 broadcasting right now?
Yes. Mode-S 7C42F9 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 7C42F9, octal 37041371, decimal 8,143,609.
What flights does 7C42F9 operate?
Mode-S 7C42F9 has broadcast 1 distinct callsign, including NIJ.