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sensors Mode-S transponder

A057DD

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N121ER · SOCATA TB-9 Tampico · operated by FREEDOM AVIATION LLC

Hex
A057DD
Octal
50053735
Decimal
10,508,253
Country
US
Tail
N121ER
Type
TAMP
Broadcasting now · callsign N121ER · 3,900 ft
Flights observed
57
Distinct callsigns
1
Country
US
Last broadcast
9h ago

Current position

A057DD is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A057DD 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
N121ER - 57 2026-07-21

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-21 N121ER - Jul 21, 16:05 UTCJul 21, 17:25 UTC1h 20m
2026-07-21 N121ER - Jul 21, 13:40 UTCJul 21, 15:10 UTC1h 30m
2026-07-20 N121ER - Jul 20, 20:00 UTCJul 20, 20:45 UTC45m
2026-07-20 N121ER - Jul 20, 16:00 UTCJul 20, 19:25 UTC3h 25m
2026-07-20 N121ER - Jul 20, 02:55 UTCJul 20, 04:10 UTC1h 15m
2026-07-19 N121ER - Jul 19, 20:55 UTCJul 19, 22:10 UTC1h 15m
2026-07-19 N121ER - Jul 19, 16:20 UTCJul 19, 20:00 UTC3h 40m
2026-07-13 N121ER - Jul 13, 19:00 UTCJul 13, 22:05 UTC3h 5m
2026-07-12 N121ER - Jul 12, 18:01 UTCJul 12, 18:40 UTC40m
2026-07-12 N121ER - Jul 12, 02:10 UTCJul 12, 05:01 UTC2h 50m
2026-07-11 N121ER - Jul 11, 17:10 UTCJul 11, 19:35 UTC2h 25m
2026-07-11 N121ER - Jul 11, 02:30 UTCJul 11, 03:10 UTC40m
2026-07-10 N121ER - Jul 10, 16:30 UTCJul 10, 19:55 UTC3h 25m
2026-07-03 N121ER - Jul 3, 17:45 UTCJul 3, 18:40 UTC55m
2026-07-03 N121ER - Jul 3, 16:45 UTCJul 3, 17:00 UTC15m
2026-07-03 N121ER - Jul 3, 05:05 UTCJul 3, 05:15 UTC10m
2026-07-03 N121ER - Jul 3, 04:45 UTCJul 3, 05:00 UTC15m
2026-07-03 N121ER - Jul 3, 02:55 UTCJul 3, 04:35 UTC1h 40m
2026-07-02 N121ER - Jul 2, 20:15 UTCJul 2, 20:55 UTC40m
2026-06-25 N121ER - Jun 25, 17:09 UTCJun 25, 18:45 UTC1h 35m
2026-06-25 N121ER - Jun 25, 02:19 UTCJun 25, 04:10 UTC1h 50m
2026-06-24 N121ER - Jun 24, 18:44 UTCJun 24, 20:09 UTC1h 25m
2026-06-24 N121ER - Jun 24, 14:29 UTCJun 24, 16:05 UTC1h 35m
2026-06-19 N121ER - Jun 19, 01:24 UTCJun 19, 02:24 UTC1h 0m
2026-06-18 N121ER - Jun 18, 19:55 UTCJun 18, 21:20 UTC1h 25m
2026-06-18 N121ER - Jun 18, 17:45 UTCJun 18, 18:40 UTC55m
2026-06-14 N121ER - Jun 14, 17:15 UTCJun 14, 18:40 UTC1h 25m
2026-06-14 N121ER - Jun 14, 14:25 UTCJun 14, 15:00 UTC35m
2026-06-14 N121ER - Jun 14, 03:40 UTCJun 14, 05:05 UTC1h 26m
2026-06-13 N121ER - Jun 13, 19:55 UTCJun 13, 21:45 UTC1h 50m
2026-06-12 N121ER - Jun 12, 18:30 UTCJun 12, 19:10 UTC40m
2026-06-11 N121ER - Jun 11, 02:35 UTCJun 11, 03:25 UTC50m
2026-06-09 N121ER - Jun 9, 20:50 UTCJun 9, 22:00 UTC1h 10m
2026-06-07 N121ER - Jun 7, 22:45 UTCJun 7, 23:15 UTC30m
2026-06-07 N121ER - Jun 7, 20:25 UTCJun 7, 21:00 UTC35m
2026-06-07 N121ER - Jun 7, 17:40 UTCJun 7, 18:15 UTC35m
2026-06-07 N121ER - Jun 7, 01:09 UTCJun 7, 01:45 UTC35m
2026-06-06 N121ER - Jun 6, 22:39 UTCJun 6, 23:44 UTC1h 5m
2026-06-06 N121ER - Jun 6, 20:25 UTCJun 6, 21:09 UTC45m
2026-06-06 N121ER - Jun 6, 17:15 UTCJun 6, 18:25 UTC1h 10m
2026-06-06 N121ER - Jun 6, 01:10 UTCJun 6, 01:40 UTC30m
2026-06-05 N121ER - Jun 5, 22:30 UTCJun 5, 23:20 UTC50m
2026-06-01 N121ER - Jun 1, 21:40 UTCJun 1, 22:05 UTC25m
2026-06-01 N121ER - Jun 1, 18:35 UTCJun 1, 19:35 UTC1h 0m
2026-06-01 N121ER - Jun 1, 01:30 UTCJun 1, 01:55 UTC25m
2026-05-31 N121ER - May 31, 22:50 UTCMay 31, 23:00 UTC10m
2026-05-13 N121ER - May 13, 04:45 UTCMay 13, 05:25 UTC40m
2026-05-13 N121ER - May 13, 01:35 UTCMay 13, 04:00 UTC2h 25m
2026-05-12 N121ER - May 12, 04:00 UTCMay 12, 04:50 UTC50m
2026-05-12 N121ER - May 12, 02:45 UTCMay 12, 03:15 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 N121ER page for operator, model, and routing details .

Mode-S A057DD frequently asked

What is Mode-S code A057DD?
A057DD is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N121ER.
Where is Mode-S A057DD registered?
Mode-S code A057DD 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 A057DD broadcasting right now?
Yes. Mode-S A057DD is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A057DD, octal 50053735, decimal 10,508,253.
What flights does A057DD operate?
Mode-S A057DD has broadcast 1 distinct callsign, including N121ER.