Apparatus

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sensors Mode-S transponder

A1D16A

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N216SP · CESSNA 172 Skyhawk · operated by NAVY ANNAPOLIS FLIGHT CENTER INC

Hex
A1D16A
Octal
50350552
Decimal
10,604,906
Country
US
Tail
N216SP
Type
C172
No current signal · last broadcast 15d ago
Flights observed
128
Distinct callsigns
1
Country
US
Last broadcast
15d ago

Last known position

Most recent position reported by Mode-S A1D16A.

Country allocation

The ICAO 24-bit address A1D16A 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
N216SP - 128 2026-07-26

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 N216SP - Jul 26, 14:35 UTCJul 26, 15:00 UTC25m
2026-07-25 N216SP - Jul 25, 19:50 UTCJul 25, 20:40 UTC50m
2026-07-25 N216SP - Jul 25, 17:40 UTCJul 25, 18:40 UTC1h 0m
2026-07-25 N216SP - Jul 25, 12:30 UTCJul 25, 13:40 UTC1h 10m
2026-07-23 N216SP - Jul 23, 16:55 UTCJul 23, 18:25 UTC1h 30m
2026-07-23 N216SP - Jul 23, 12:40 UTCJul 23, 13:40 UTC1h 0m
2026-07-22 N216SP ANP → ANP Jul 22, 20:50 UTCJul 22, 22:20 UTC1h 30m
2026-07-22 N216SP ANP → ANP Jul 22, 17:45 UTCJul 22, 18:40 UTC55m
2026-07-22 N216SP - Jul 22, 15:35 UTCJul 22, 16:35 UTC1h 0m
2026-07-20 N216SP - Jul 20, 22:55 UTCJul 21, 00:30 UTC1h 34m
2026-07-20 N216SP - Jul 20, 16:50 UTCJul 20, 17:45 UTC55m
2026-07-20 N216SP - Jul 20, 14:35 UTCJul 20, 15:35 UTC1h 0m
2026-07-19 N216SP ANP → ANP Jul 19, 13:25 UTCJul 19, 14:20 UTC55m
2026-07-16 N216SP ESN → ANP Jul 16, 12:05 UTCJul 16, 12:40 UTC35m
2026-07-16 N216SP ANP → ESN Jul 16, 11:25 UTCJul 16, 12:00 UTC35m
2026-07-15 N216SP ANP → ANP Jul 15, 14:50 UTCJul 15, 15:45 UTC55m
2026-07-14 N216SP - Jul 14, 18:15 UTCJul 14, 18:40 UTC25m
2026-07-14 N216SP - Jul 14, 16:55 UTCJul 14, 17:30 UTC35m
2026-07-14 N216SP - Jul 14, 14:10 UTCJul 14, 15:00 UTC50m
2026-07-14 N216SP - Jul 14, 13:00 UTCJul 14, 13:15 UTC15m
2026-07-14 N216SP - Jul 14, 12:10 UTCJul 14, 12:55 UTC45m
2026-07-13 N216SP - Jul 13, 22:25 UTCJul 13, 23:40 UTC1h 15m
2026-07-13 N216SP - Jul 13, 20:35 UTCJul 13, 21:30 UTC55m
2026-07-13 N216SP - Jul 13, 17:10 UTCJul 13, 18:25 UTC1h 15m
2026-07-13 N216SP - Jul 13, 12:55 UTCJul 13, 13:45 UTC50m
2026-07-11 N216SP - Jul 11, 16:00 UTCJul 11, 17:40 UTC1h 40m
2026-07-11 N216SP - Jul 11, 11:40 UTCJul 11, 12:40 UTC1h 0m
2026-07-10 N216SP - Jul 10, 17:25 UTCJul 10, 17:35 UTC10m
2026-07-10 N216SP - Jul 10, 15:10 UTCJul 10, 16:35 UTC1h 25m
2026-06-18 N216SP - Jun 18, 01:00 UTCJun 18, 01:55 UTC55m
2026-06-17 N216SP - Jun 17, 18:40 UTCJun 17, 19:20 UTC40m
2026-06-17 N216SP - Jun 17, 16:35 UTCJun 17, 17:55 UTC1h 20m
2026-06-17 N216SP - Jun 17, 14:50 UTCJun 17, 16:00 UTC1h 10m
2026-06-16 N216SP ANP → ANP Jun 16, 20:50 UTCJun 16, 21:45 UTC55m
2026-06-16 N216SP - Jun 16, 18:35 UTCJun 16, 19:40 UTC1h 5m
2026-06-16 N216SP - Jun 16, 14:55 UTCJun 16, 16:00 UTC1h 5m
2026-06-15 N216SP - Jun 15, 19:55 UTCJun 15, 20:50 UTC55m
2026-06-15 N216SP - Jun 15, 16:35 UTCJun 15, 17:34 UTC1h 0m
2026-06-15 N216SP ANP → ANP Jun 15, 14:10 UTCJun 15, 15:04 UTC55m
2026-06-14 N216SP ANP → ANP Jun 14, 19:00 UTCJun 14, 19:50 UTC50m
2026-06-14 N216SP - Jun 14, 16:45 UTCJun 14, 18:05 UTC1h 20m
2026-06-14 N216SP - Jun 14, 13:55 UTCJun 14, 14:50 UTC55m
2026-06-13 N216SP ANP → ANP Jun 13, 15:35 UTCJun 13, 17:00 UTC1h 25m
2026-06-12 N216SP ANP → ANP Jun 12, 15:30 UTCJun 12, 16:45 UTC1h 15m
2026-06-09 N216SP - Jun 9, 17:35 UTCJun 9, 19:00 UTC1h 25m
2026-06-09 N216SP - Jun 9, 12:40 UTCJun 9, 13:35 UTC55m
2026-06-08 N216SP ANP → ANP Jun 8, 14:40 UTCJun 8, 15:20 UTC40m
2026-06-08 N216SP - Jun 8, 12:35 UTCJun 8, 13:25 UTC50m
2026-06-07 N216SP - Jun 7, 17:30 UTCJun 7, 18:30 UTC1h 0m
2026-06-06 N216SP ANP → ANP Jun 6, 20:25 UTCJun 6, 21:25 UTC1h 0m

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 N216SP page for operator, model, and routing details .

Mode-S A1D16A frequently asked

What is Mode-S code A1D16A?
A1D16A is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N216SP.
Where is Mode-S A1D16A registered?
Mode-S code A1D16A 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 A1D16A broadcasting right now?
No active broadcast right now. Last signal was 15d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A1D16A, octal 50350552, decimal 10,604,906.
What flights does A1D16A operate?
Mode-S A1D16A has broadcast 1 distinct callsign, including N216SP.