Apparatus

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sensors Mode-S transponder

A3971C

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N330PH · AIRBUS HELICOPTERS EC-135/635 · operated by PHI HEALTH LLC

Hex
A3971C
Octal
50713434
Decimal
10,721,052
Country
US
Tail
N330PH
Type
EC35
No current signal · last broadcast 3d ago
Flights observed
154
Distinct callsigns
2
Country
US
Last broadcast
3d ago

Last known position

Most recent position reported by Mode-S A3971C.

Country allocation

The ICAO 24-bit address A3971C 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 2 distinct

Callsign Airline Flights Last seen
N330PH - 146 2026-07-19
LN330PH - 3 2026-05-09

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-19 N330PH - Jul 19, 21:30 UTCJul 19, 21:55 UTC25m
2026-07-19 N330PH - Jul 19, 20:05 UTCJul 19, 20:20 UTC15m
2026-07-19 N330PH - Jul 19, 08:20 UTCJul 19, 08:40 UTC20m
2026-07-19 N330PH - Jul 19, 04:00 UTCJul 19, 04:25 UTC25m
2026-07-18 N330PH - Jul 18, 16:10 UTCJul 18, 16:20 UTC10m
2026-07-18 N330PH - Jul 18, 14:35 UTCJul 18, 15:05 UTC30m
2026-07-18 N330PH - Jul 18, 13:10 UTCJul 18, 13:35 UTC25m
2026-07-18 N330PH - Jul 18, 07:35 UTCJul 18, 08:05 UTC30m
2026-07-18 N330PH - Jul 18, 05:55 UTCJul 18, 06:25 UTC30m
2026-07-18 N330PH - Jul 18, 03:20 UTCJul 18, 03:45 UTC25m
2026-07-18 N330PH - Jul 18, 02:05 UTCJul 18, 02:25 UTC20m
2026-07-16 N330PH - Jul 16, 09:15 UTCJul 16, 09:25 UTC10m
2026-07-16 N330PH - Jul 16, 07:45 UTCJul 16, 08:15 UTC30m
2026-07-16 N330PH - Jul 16, 06:10 UTCJul 16, 06:50 UTC40m
2026-07-16 N330PH - Jul 16, 05:30 UTCJul 16, 05:45 UTC15m
2026-07-16 N330PH - Jul 16, 03:00 UTCJul 16, 03:10 UTC10m
2026-07-16 N330PH - Jul 16, 01:45 UTCJul 16, 02:15 UTC30m
2026-07-16 N330PH - Jul 16, 00:05 UTCJul 16, 00:25 UTC20m
2026-07-15 N330PH - Jul 15, 03:00 UTCJul 15, 03:10 UTC10m
2026-07-14 N330PH - Jul 14, 23:35 UTCJul 14, 23:50 UTC15m
2026-07-11 N330PH - Jul 11, 19:45 UTCJul 11, 19:55 UTC10m
2026-07-11 N330PH - Jul 11, 18:30 UTCJul 11, 19:00 UTC30m
2026-07-11 N330PH - Jul 11, 16:30 UTCJul 11, 17:00 UTC30m
2026-07-11 N330PH - Jul 11, 08:15 UTCJul 11, 08:25 UTC10m
2026-07-11 N330PH - Jul 11, 07:10 UTCJul 11, 07:35 UTC25m
2026-07-11 N330PH - Jul 11, 05:15 UTCJul 11, 05:45 UTC30m
2026-07-09 N330PH - Jul 9, 01:30 UTCJul 9, 01:55 UTC25m
2026-07-08 N330PH - Jul 8, 23:30 UTCJul 9, 00:05 UTC35m
2026-07-08 N330PH - Jul 8, 18:50 UTCJul 8, 19:00 UTC10m
2026-07-08 N330PH - Jul 8, 16:40 UTCJul 8, 17:10 UTC30m
2026-07-08 - - Jul 8, 15:05 UTCJul 8, 15:25 UTC20m
2026-07-02 N330PH - Jul 2, 18:35 UTCJul 2, 18:45 UTC10m
2026-07-02 N330PH - Jul 2, 17:25 UTCJul 2, 17:40 UTC15m
2026-07-02 N330PH - Jul 2, 15:50 UTCJul 2, 16:10 UTC20m
2026-07-01 N330PH - Jul 1, 05:40 UTCJul 1, 05:50 UTC10m
2026-07-01 N330PH - Jul 1, 04:20 UTCJul 1, 04:35 UTC15m
2026-07-01 N330PH - Jul 1, 03:00 UTCJul 1, 03:15 UTC15m
2026-06-28 N330PH - Jun 28, 03:29 UTCJun 28, 03:40 UTC10m
2026-06-28 N330PH - Jun 28, 02:34 UTCJun 28, 02:54 UTC20m
2026-06-28 N330PH - Jun 28, 01:34 UTCJun 28, 01:44 UTC10m
2026-06-26 N330PH - Jun 26, 23:04 UTCJun 26, 23:34 UTC30m
2026-06-26 N330PH - Jun 26, 20:59 UTCJun 26, 21:24 UTC25m
2026-06-26 N330PH - Jun 26, 19:20 UTCJun 26, 20:15 UTC55m
2026-06-25 N330PH - Jun 25, 18:55 UTCJun 25, 19:59 UTC1h 5m
2026-06-25 N330PH - Jun 25, 18:00 UTCJun 25, 18:15 UTC15m
2026-06-25 N330PH - Jun 25, 16:59 UTCJun 25, 17:09 UTC10m
2026-06-25 N330PH - Jun 25, 16:05 UTCJun 25, 16:20 UTC15m
2026-06-25 N330PH - Jun 25, 14:55 UTCJun 25, 15:20 UTC25m
2026-06-24 N330PH - Jun 24, 21:50 UTCJun 24, 22:00 UTC10m
2026-06-24 N330PH - Jun 24, 20:44 UTCJun 24, 21:04 UTC20m

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 N330PH page for operator, model, and routing details .

Mode-S A3971C frequently asked

What is Mode-S code A3971C?
A3971C is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N330PH.
Where is Mode-S A3971C registered?
Mode-S code A3971C 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 A3971C 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 A3971C, octal 50713434, decimal 10,721,052.
What flights does A3971C operate?
Mode-S A3971C has broadcast 2 distinct callsigns, including N330PH, LN330PH.