sensors Mode-S transponder

A4C1D2

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N504HW · operated by FARM AIR FLYING SERVICE LLC (Miscode)

Hex
A4C1D2
Octal
51140722
Decimal
10,797,522
Country
US
Tail
N504HW
Type
AT5T
No current signal · last broadcast 3d ago
Flights observed
185
Distinct callsigns
1
Country
US
Last broadcast
3d ago

Last known position

Most recent position reported by Mode-S A4C1D2.

Country allocation

The ICAO 24-bit address A4C1D2 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 1 distinct

Callsign Airline Flights Last seen
504HW - 185 2026-07-20

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-20 504HW - Jul 20, 17:30 UTCJul 20, 18:25 UTC55m
2026-07-20 504HW - Jul 20, 14:50 UTCJul 20, 15:05 UTC15m
2026-07-20 504HW - Jul 20, 13:50 UTCJul 20, 14:35 UTC45m
2026-07-18 504HW - Jul 18, 13:35 UTCJul 18, 14:00 UTC25m
2026-07-17 504HW - Jul 17, 14:24 UTCJul 17, 14:55 UTC30m
2026-07-16 504HW - Jul 16, 13:30 UTCJul 16, 14:10 UTC40m
2026-07-15 504HW - Jul 15, 14:25 UTCJul 15, 15:00 UTC35m
2026-07-15 504HW - Jul 15, 14:10 UTCJul 15, 14:20 UTC10m
2026-07-15 504HW - Jul 15, 13:40 UTCJul 15, 14:00 UTC20m
2026-07-14 504HW - Jul 14, 13:35 UTCJul 14, 14:55 UTC1h 20m
2026-07-13 504HW - Jul 13, 17:10 UTCJul 13, 18:10 UTC1h 0m
2026-07-13 504HW - Jul 13, 15:50 UTCJul 13, 16:35 UTC45m
2026-07-13 504HW - Jul 13, 14:40 UTCJul 13, 15:45 UTC1h 5m
2026-07-13 504HW - Jul 13, 13:35 UTCJul 13, 14:30 UTC55m
2026-07-11 504HW - Jul 11, 13:55 UTCJul 11, 14:30 UTC35m
2026-07-11 504HW - Jul 11, 13:30 UTCJul 11, 13:45 UTC15m
2026-07-10 504HW - Jul 10, 21:55 UTCJul 10, 22:30 UTC35m
2026-07-10 504HW - Jul 10, 18:30 UTCJul 10, 18:40 UTC10m
2026-07-10 504HW - Jul 10, 18:10 UTCJul 10, 18:25 UTC15m
2026-07-10 504HW - Jul 10, 17:05 UTCJul 10, 18:05 UTC1h 0m
2026-07-10 504HW - Jul 10, 16:20 UTCJul 10, 16:45 UTC25m
2026-07-10 504HW - Jul 10, 15:55 UTCJul 10, 16:05 UTC10m
2026-07-10 504HW - Jul 10, 13:40 UTCJul 10, 15:50 UTC2h 10m
2026-07-09 504HW - Jul 9, 13:45 UTCJul 9, 15:50 UTC2h 5m
2026-07-08 504HW - Jul 8, 17:20 UTCJul 8, 19:15 UTC1h 55m
2026-07-08 504HW - Jul 8, 14:05 UTCJul 8, 17:15 UTC3h 10m
2026-07-08 504HW - Jul 8, 13:30 UTCJul 8, 14:00 UTC30m
2026-07-07 504HW - Jul 7, 13:55 UTCJul 7, 14:35 UTC40m
2026-07-06 504HW - Jul 6, 19:20 UTCJul 6, 19:50 UTC30m
2026-07-06 504HW - Jul 6, 18:45 UTCJul 6, 19:10 UTC25m
2026-07-06 504HW - Jul 6, 16:40 UTCJul 6, 18:35 UTC1h 55m
2026-07-06 504HW - Jul 6, 16:00 UTCJul 6, 16:35 UTC35m
2026-07-06 504HW - Jul 6, 12:50 UTCJul 6, 15:50 UTC3h 0m
2026-07-03 504HW - Jul 3, 16:20 UTCJul 3, 18:00 UTC1h 40m
2026-07-03 504HW - Jul 3, 15:30 UTCJul 3, 16:15 UTC45m
2026-07-03 504HW - Jul 3, 15:00 UTCJul 3, 15:25 UTC25m
2026-07-03 504HW - Jul 3, 14:15 UTCJul 3, 14:55 UTC40m
2026-07-03 504HW - Jul 3, 13:30 UTCJul 3, 14:10 UTC40m
2026-07-02 504HW - Jul 2, 19:35 UTCJul 2, 20:10 UTC35m
2026-07-02 504HW - Jul 2, 19:15 UTCJul 2, 19:30 UTC15m
2026-07-02 504HW - Jul 2, 17:55 UTCJul 2, 19:10 UTC1h 15m
2026-07-02 504HW - Jul 2, 16:35 UTCJul 2, 17:50 UTC1h 15m
2026-07-02 504HW - Jul 2, 16:05 UTCJul 2, 16:30 UTC25m
2026-07-02 504HW - Jul 2, 13:20 UTCJul 2, 16:00 UTC2h 40m
2026-07-01 504HW - Jul 1, 20:55 UTCJul 1, 22:05 UTC1h 10m
2026-07-01 504HW - Jul 1, 17:00 UTCJul 1, 20:50 UTC3h 50m
2026-07-01 504HW - Jul 1, 16:00 UTCJul 1, 16:25 UTC25m
2026-07-01 504HW - Jul 1, 13:35 UTCJul 1, 15:55 UTC2h 20m
2026-06-30 504HW - Jun 30, 15:35 UTCJun 30, 15:50 UTC15m
2026-06-30 504HW - Jun 30, 14:30 UTCJun 30, 15:00 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 N504HW page for operator, model, and routing details .

Mode-S A4C1D2 frequently asked

What is Mode-S code A4C1D2?
A4C1D2 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N504HW.
Where is Mode-S A4C1D2 registered?
Mode-S code A4C1D2 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 A4C1D2 broadcasting right now?
No active broadcast right now. Last signal was 3d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A4C1D2, octal 51140722, decimal 10,797,522.
What flights does A4C1D2 operate?
Mode-S A4C1D2 has broadcast 1 distinct callsign, including 504HW.