Apparatus

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sensors Mode-S transponder

AB3506

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N821ER · CESSNA 172 Skyhawk · operated by EMBRY RIDDLE AERONAUTICAL UNIVERSITY

Hex
AB3506
Octal
52632406
Decimal
11,220,230
Country
US
Tail
N821ER
Type
C172
No current signal · last broadcast 20d ago
Flights observed
196
Distinct callsigns
1
Country
US
Last broadcast
20d ago

Last known position

Most recent position reported by Mode-S AB3506.

Country allocation

The ICAO 24-bit address AB3506 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
ERU821 - 196 2026-07-26

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 ERU821 - Jul 26, 12:35 UTCJul 26, 14:35 UTC2h 0m
2026-07-26 ERU821 - Jul 26, 00:45 UTCJul 26, 02:00 UTC1h 15m
2026-07-25 ERU821 - Jul 25, 15:45 UTCJul 25, 16:55 UTC1h 10m
2026-07-25 ERU821 - Jul 25, 13:15 UTCJul 25, 14:10 UTC55m
2026-07-25 ERU821 - Jul 25, 01:40 UTCJul 25, 02:55 UTC1h 15m
2026-07-24 ERU821 - Jul 24, 15:05 UTCJul 24, 16:50 UTC1h 45m
2026-07-24 ERU821 - Jul 24, 10:50 UTCJul 24, 12:20 UTC1h 30m
2026-07-23 ERU821 - Jul 23, 19:40 UTCJul 23, 21:50 UTC2h 10m
2026-07-23 ERU821 - Jul 23, 16:20 UTCJul 23, 16:35 UTC15m
2026-07-23 ERU821 - Jul 23, 15:20 UTCJul 23, 15:30 UTC10m
2026-07-23 ERU821 - Jul 23, 12:55 UTCJul 23, 13:40 UTC45m
2026-07-22 ERU821 - Jul 22, 20:15 UTCJul 22, 21:55 UTC1h 40m
2026-07-22 ERU821 - Jul 22, 15:40 UTCJul 22, 16:50 UTC1h 10m
2026-07-22 ERU821 - Jul 22, 11:40 UTCJul 22, 12:20 UTC40m
2026-07-21 ERU821 - Jul 21, 18:15 UTCJul 21, 18:45 UTC30m
2026-07-20 ERU821 - Jul 20, 17:40 UTCJul 20, 19:15 UTC1h 35m
2026-07-20 ERU821 - Jul 20, 10:50 UTCJul 20, 11:55 UTC1h 5m
2026-07-19 ERU821 - Jul 19, 12:30 UTCJul 19, 14:05 UTC1h 35m
2026-07-18 ERU821 - Jul 18, 18:30 UTCJul 18, 19:50 UTC1h 20m
2026-07-18 ERU821 - Jul 18, 01:20 UTCJul 18, 03:00 UTC1h 41m
2026-07-17 ERU821 - Jul 17, 15:20 UTCJul 17, 15:29 UTC10m
2026-07-17 ERU821 - Jul 17, 11:39 UTCJul 17, 13:20 UTC1h 40m
2026-07-16 ERU821 - Jul 16, 19:50 UTCJul 16, 20:00 UTC10m
2026-07-16 ERU821 - Jul 16, 13:34 UTCJul 16, 15:05 UTC1h 30m
2026-07-16 ERU821 - Jul 16, 10:25 UTCJul 16, 11:10 UTC45m
2026-07-15 ERU821 - Jul 15, 18:40 UTCJul 15, 19:35 UTC55m
2026-07-15 ERU821 - Jul 15, 13:10 UTCJul 15, 14:25 UTC1h 15m
2026-07-15 ERU821 - Jul 15, 01:25 UTCJul 15, 02:00 UTC35m
2026-07-14 ERU821 - Jul 14, 13:55 UTCJul 14, 15:30 UTC1h 35m
2026-07-14 ERU821 - Jul 14, 09:55 UTCJul 14, 11:25 UTC1h 30m
2026-07-13 ERU821 - Jul 13, 16:00 UTCJul 13, 18:05 UTC2h 5m
2026-07-13 ERU821 - Jul 13, 10:55 UTCJul 13, 12:05 UTC1h 10m
2026-07-12 ERU821 - Jul 12, 15:20 UTCJul 12, 15:45 UTC25m
2026-07-12 ERU821 - Jul 12, 12:50 UTCJul 12, 13:30 UTC40m
2026-07-12 ERU821 - Jul 12, 00:50 UTCJul 12, 01:25 UTC35m
2026-07-11 ERU821 - Jul 11, 16:05 UTCJul 11, 17:25 UTC1h 20m
2026-07-11 ERU821 - Jul 11, 12:35 UTCJul 11, 14:15 UTC1h 40m
2026-07-10 ERU821 - Jul 10, 23:40 UTCJul 11, 00:15 UTC35m
2026-07-10 ERU821 - Jul 10, 20:05 UTCJul 10, 20:35 UTC30m
2026-07-10 ERU821 - Jul 10, 18:20 UTCJul 10, 19:10 UTC50m
2026-07-10 ERU821 - Jul 10, 13:25 UTCJul 10, 15:10 UTC1h 45m
2026-07-10 ERU821 - Jul 10, 11:05 UTCJul 10, 12:05 UTC1h 0m
2026-07-10 ERU821 - Jul 10, 01:40 UTCJul 10, 01:50 UTC10m
2026-07-09 ERU821 - Jul 9, 23:40 UTCJul 10, 00:45 UTC1h 5m
2026-07-09 ERU821 - Jul 9, 18:15 UTCJul 9, 19:55 UTC1h 40m
2026-07-09 ERU821 - Jul 9, 13:00 UTCJul 9, 14:30 UTC1h 30m
2026-07-01 ERU821 - Jul 1, 10:35 UTCJul 1, 11:30 UTC55m
2026-06-30 ERU821 - Jun 30, 15:05 UTCJun 30, 15:20 UTC15m
2026-06-30 ERU821 - Jun 30, 13:20 UTCJun 30, 14:10 UTC50m
2026-06-29 ERU821 - Jun 29, 16:55 UTCJun 29, 17:19 UTC25m

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 N821ER page for operator, model, and routing details .

Mode-S AB3506 frequently asked

What is Mode-S code AB3506?
AB3506 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N821ER.
Where is Mode-S AB3506 registered?
Mode-S code AB3506 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 AB3506 broadcasting right now?
No active broadcast right now. Last signal was 20d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AB3506, octal 52632406, decimal 11,220,230.
What flights does AB3506 operate?
Mode-S AB3506 has broadcast 1 distinct callsign, including ERU821.