sensors Mode-S transponder

A73A1C

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N565GJ · operated by UNITED AIRLINES INC

Hex
A73A1C
Octal
51635034
Decimal
10,959,388
Country
US
Tail
N565GJ
Type
CRJ7
No current signal · last broadcast 1d ago
Flights observed
8
Distinct callsigns
6
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S A73A1C.

Country allocation

The ICAO 24-bit address A73A1C falls within the block assigned to United States (US) by ICAO Annex 10, Volume III. Every aircraft registered in United States 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 6 distinct

Callsign Airline Flights Last seen
GJS4479 - 2 2026-04-13
GJS4421 - 2 2026-04-13
GJS4593 - 1 2026-04-13
GJS4501 GoJet Airlines 1 2026-04-13
GJS4409 - 1 2026-04-12
GJS4391 - 1 2026-04-13

Recent flights last 8

DateFlightRouteTakeoffLandingDuration
2026-04-13 GJS4593 - Apr 13, 21:12 UTCApr 13, 22:31 UTC1h 19m
2026-04-13 GJS4501 SCE → EWR Apr 13, 18:10 UTCApr 13, 19:31 UTC1h 21m
2026-04-13 GJS4479 - Apr 13, 16:15 UTCApr 13, 17:05 UTC50m
2026-04-13 GJS4479 - Apr 13, 15:55 UTCApr 13, 16:15 UTC20m
2026-04-13 GJS4421 - Apr 13, 13:23 UTCApr 13, 14:29 UTC1h 6m
2026-04-13 GJS4421 - Apr 13, 13:23 UTCApr 13, 14:24 UTC1h 1m
2026-04-13 GJS4391 - Apr 13, 01:30 UTCApr 13, 02:40 UTC1h 10m
2026-04-12 GJS4409 - Apr 12, 17:15 UTCApr 12, 18:20 UTC1h 5m

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 N565GJ page for operator, model, and routing details .

Mode-S A73A1C frequently asked

What is Mode-S code A73A1C?
A73A1C is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N565GJ.
Where is Mode-S A73A1C registered?
Mode-S code A73A1C is allocated to United States (US). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is A73A1C broadcasting right now?
No active broadcast right now. Last signal was 1d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A73A1C, octal 51635034, decimal 10,959,388.
What flights does A73A1C operate?
Mode-S A73A1C has broadcast 6 distinct callsigns, including GJS4479, GJS4421, GJS4593, GJS4501, GJS4409.