Apparatus

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sensors Mode-S transponder

ACD1D4

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N925MD · BELL 407 · operated by AIR METHODS LLC

Hex
ACD1D4
Octal
53150724
Decimal
11,325,908
Country
US
Tail
N925MD
Type
B407
No current signal · last broadcast Jul 26, 22:35 UTC
Flights observed
102
Distinct callsigns
1
Country
US
Last broadcast
Jul 26, 22:35 UTC

Last known position

Most recent position reported by Mode-S ACD1D4.

Country allocation

The ICAO 24-bit address ACD1D4 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
N925MD - 101 2026-07-26

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 N925MD - Jul 26, 22:25 UTCJul 26, 22:35 UTC10m
2026-07-26 N925MD - Jul 26, 16:00 UTCJul 26, 16:20 UTC20m
2026-07-26 N925MD - Jul 26, 15:20 UTCJul 26, 15:30 UTC10m
2026-07-26 N925MD - Jul 26, 14:10 UTCJul 26, 14:25 UTC15m
2026-07-25 N925MD - Jul 25, 22:55 UTCJul 25, 23:30 UTC35m
2026-07-25 N925MD - Jul 25, 21:25 UTCJul 25, 21:35 UTC10m
2026-07-23 N925MD - Jul 23, 06:25 UTCJul 23, 07:15 UTC50m
2026-07-23 N925MD - Jul 23, 05:15 UTCJul 23, 05:25 UTC10m
2026-07-22 N925MD - Jul 22, 19:00 UTCJul 22, 19:15 UTC15m
2026-07-22 N925MD - Jul 22, 17:20 UTCJul 22, 17:35 UTC15m
2026-07-21 N925MD - Jul 21, 02:00 UTCJul 21, 02:15 UTC15m
2026-07-20 N925MD - Jul 20, 20:15 UTCJul 20, 20:35 UTC20m
2026-07-20 N925MD - Jul 20, 19:00 UTCJul 20, 19:10 UTC10m
2026-07-18 N925MD - Jul 18, 02:19 UTCJul 18, 03:30 UTC1h 11m
2026-07-14 N925MD - Jul 14, 00:25 UTCJul 14, 00:55 UTC30m
2026-07-13 N925MD - Jul 13, 23:30 UTCJul 13, 23:55 UTC25m
2026-07-12 N925MD - Jul 12, 23:40 UTCJul 12, 23:55 UTC15m
2026-07-12 N925MD - Jul 12, 22:05 UTCJul 12, 22:15 UTC10m
2026-07-12 N925MD - Jul 12, 04:15 UTCJul 12, 05:15 UTC1h 0m
2026-07-12 N925MD - Jul 12, 02:01 UTCJul 12, 02:20 UTC20m
2026-07-11 N925MD - Jul 11, 21:00 UTCJul 11, 21:55 UTC55m
2026-07-11 N925MD - Jul 11, 19:10 UTCJul 11, 19:20 UTC10m
2026-07-10 N925MD - Jul 10, 14:40 UTCJul 10, 14:50 UTC10m
2026-07-08 N925MD - Jul 8, 04:40 UTCJul 8, 04:50 UTC10m
2026-07-07 N925MD - Jul 7, 23:20 UTCJul 7, 23:40 UTC20m
2026-07-07 N925MD - Jul 7, 21:25 UTCJul 7, 21:30 UTC5m
2026-07-07 N925MD - Jul 7, 20:00 UTCJul 7, 20:20 UTC20m
2026-07-07 N925MD - Jul 7, 03:00 UTCJul 7, 03:30 UTC30m
2026-07-07 N925MD - Jul 7, 02:15 UTCJul 7, 02:25 UTC10m
2026-07-04 N925MD - Jul 4, 03:35 UTCJul 4, 03:45 UTC10m
2026-07-04 N925MD - Jul 4, 03:00 UTCJul 4, 03:10 UTC10m
2026-07-04 N925MD - Jul 4, 02:05 UTCJul 4, 02:20 UTC15m
2026-07-01 N925MD - Jul 1, 21:10 UTCJul 1, 21:30 UTC20m
2026-07-01 N925MD - Jul 1, 19:45 UTCJul 1, 19:55 UTC10m
2026-06-29 N925MD - Jun 29, 14:54 UTCJun 29, 15:00 UTC5m
2026-06-26 N925MD - Jun 26, 20:29 UTCJun 26, 20:44 UTC15m
2026-06-24 N925MD - Jun 24, 23:04 UTCJun 24, 23:20 UTC15m
2026-06-12 N925MD - Jun 12, 14:50 UTCJun 12, 15:10 UTC20m
2026-06-11 N925MD - Jun 11, 10:50 UTCJun 11, 11:30 UTC40m
2026-06-11 N925MD - Jun 11, 09:40 UTCJun 11, 10:00 UTC20m
2026-06-11 - - Jun 11, 08:05 UTCJun 11, 08:15 UTC10m
2026-06-10 N925MD - Jun 10, 12:00 UTCJun 10, 12:15 UTC15m
2026-06-09 N925MD - Jun 9, 19:30 UTCJun 9, 19:45 UTC15m
2026-06-09 N925MD - Jun 9, 17:25 UTCJun 9, 17:40 UTC15m
2026-06-05 N925MD - Jun 5, 19:05 UTCJun 5, 19:30 UTC25m
2026-06-05 N925MD - Jun 5, 18:20 UTCJun 5, 18:30 UTC10m
2026-06-03 N925MD - Jun 3, 20:00 UTCJun 3, 21:05 UTC1h 5m
2026-06-02 N925MD - Jun 2, 04:05 UTCJun 2, 04:55 UTC50m
2026-06-02 N925MD - Jun 2, 03:10 UTCJun 2, 03:25 UTC15m
2026-05-31 N925MD - May 31, 21:00 UTCMay 31, 21:15 UTC15m

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 N925MD page for operator, model, and routing details .

Mode-S ACD1D4 frequently asked

What is Mode-S code ACD1D4?
ACD1D4 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N925MD.
Where is Mode-S ACD1D4 registered?
Mode-S code ACD1D4 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 ACD1D4 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 22:35 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex ACD1D4, octal 53150724, decimal 11,325,908.
What flights does ACD1D4 operate?
Mode-S ACD1D4 has broadcast 1 distinct callsign, including N925MD.