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sensors Mode-S transponder

A4DDCA

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N412YX · EMBRAER ERJ-170-200 (long wing) · operated by REPUBLIC AIRWAYS INC

Hex
A4DDCA
Octal
51156712
Decimal
10,804,682
Country
US
Tail
N412YX
Type
E75L
No current signal · last broadcast Jul 26, 22:30 UTC
Flights observed
757
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 22:30 UTC

Last known position

Most recent position reported by Mode-S A4DDCA.

Country allocation

The ICAO 24-bit address A4DDCA 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 20 distinct

Callsign Airline Flights Last seen
RPA4393 - 10 2026-07-19
RPA4729 Republic Airlines 8 2026-05-29
RPA4606 - 8 2026-07-26
RPA4396 Republic Airlines 8 2026-06-02
RPA4725 - 7 2026-07-11
RPA4654 - 7 2026-07-15
RPA4561 Republic Airlines 7 2026-05-04
RPA4540 - 7 2026-06-14
RPA4408 Republic Airlines 7 2026-07-20
RPA4399 - 7 2026-07-10
RPA4380 - 7 2026-07-15
RPA4379 - 7 2026-07-14
RPA4364 - 7 2026-06-24
RPA4778 Republic Airlines 6 2026-05-23
RPA4726 - 6 2026-06-21
RPA4713 Republic Airlines 6 2026-06-13
RPA4700 - 6 2026-07-16
RPA4551 - 6 2026-07-20
RPA4541 - 6 2026-07-17
RPA4456 - 6 2026-06-23

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 RPA4596 BOS → CMH Jul 26, 22:15 UTCJul 26, 22:30 UTC15m
2026-07-26 RPA4372 MEM → PHL Jul 26, 19:05 UTCJul 26, 20:55 UTC1h 50m
2026-07-26 RPA4606 ATL → LGA Jul 26, 16:10 UTCJul 26, 18:00 UTC1h 50m
2026-07-26 RPA4606 LGA → ATL Jul 26, 13:05 UTCJul 26, 14:45 UTC1h 40m
2026-07-25 RPA4475 PHL → IAH Jul 25, 20:20 UTCJul 25, 22:40 UTC2h 20m
2026-07-25 RPA4475 PHL → IAH Jul 25, 15:50 UTCJul 25, 18:35 UTC2h 45m
2026-07-25 RPA4564 SDF → BOS Jul 25, 12:15 UTCJul 25, 14:30 UTC2h 15m
2026-07-25 RPA4564 SDF → BOS Jul 25, 12:10 UTCJul 25, 14:26 UTC2h 16m
2026-07-25 RPA4696 MSP → PHL Jul 25, 00:33 UTCJul 25, 02:49 UTC2h 16m
2026-07-25 RPA4696 MSP → PHL Jul 25, 00:35 UTCJul 25, 02:50 UTC2h 15m
2026-07-24 RPA4378 BOS → JFK Jul 24, 22:20 UTCJul 24, 23:15 UTC55m
2026-07-24 RPA4378 BOS → JFK Jul 24, 20:35 UTCJul 24, 21:30 UTC55m
2026-07-24 RPA4606 ATL → LGA Jul 24, 17:10 UTCJul 24, 19:05 UTC1h 55m
2026-07-24 RPA4606 LGA → ATL Jul 24, 13:50 UTCJul 24, 16:05 UTC2h 15m
2026-07-24 RPA4799 - Jul 24, 10:50 UTCJul 24, 12:15 UTC1h 25m
2026-07-23 RPA4462 LGA → CMH Jul 23, 21:45 UTCJul 23, 23:10 UTC1h 25m
2026-07-23 RPA4773 GSO → LGA Jul 23, 19:15 UTCJul 23, 19:55 UTC40m
2026-07-23 RPA4754 MIA → BUF Jul 23, 16:40 UTCJul 23, 17:35 UTC55m
2026-07-23 RPA4754 MIA → BUF Jul 23, 15:05 UTCJul 23, 15:55 UTC50m
2026-07-23 RPA4491 LGA → DCA Jul 23, 12:15 UTCJul 23, 13:05 UTC50m
2026-07-23 RPA4560 PIT → LGA Jul 23, 01:50 UTCJul 23, 02:50 UTC1h 0m
2026-07-22 RPA4596 BOS → CMH Jul 22, 22:20 UTCJul 22, 23:25 UTC1h 5m
2026-07-22 RPA4372 MEM → PHL Jul 22, 19:10 UTCJul 22, 21:20 UTC2h 10m
2026-07-22 RPA4620 LGA → RIC Jul 22, 15:05 UTCJul 22, 17:25 UTC2h 20m
2026-07-22 RPA4620 LGA → RIC Jul 22, 11:45 UTCJul 22, 14:20 UTC2h 35m
2026-07-21 RPA4581 MEM → LGA Jul 21, 11:15 UTCJul 21, 14:00 UTC2h 45m
2026-07-20 RPA4341 DCA → SYR Jul 20, 23:55 UTCJul 21, 02:35 UTC2h 40m
2026-07-20 RPA4617 - Jul 20, 21:30 UTCJul 20, 22:45 UTC1h 15m
2026-07-20 RPA4767 JFK → CMH Jul 20, 19:10 UTCJul 20, 20:25 UTC1h 15m
2026-07-20 RPA4767 JFK → CMH Jul 20, 19:10 UTCJul 20, 20:24 UTC1h 14m
2026-07-20 RPA4408 YYZ → ORD Jul 20, 16:05 UTCJul 20, 16:30 UTC25m
2026-07-20 RPA4408 YYZ → ORD Jul 20, 16:04 UTCJul 20, 17:40 UTC1h 36m
2026-07-20 RPA4408 YYZ → ORD Jul 20, 13:20 UTCJul 20, 14:50 UTC1h 30m
2026-07-20 RPA4551 DCA → JFK Jul 20, 10:50 UTCJul 20, 11:30 UTC40m
2026-07-19 RPA4416 JFK → CMH Jul 19, 17:05 UTCJul 19, 19:10 UTC2h 5m
2026-07-19 RPA4416 JFK → CMH Jul 19, 16:57 UTCJul 19, 19:11 UTC2h 14m
2026-07-19 RPA4416 JFK → CMH Jul 19, 12:50 UTCJul 19, 15:30 UTC2h 40m
2026-07-19 RPA4690 - Jul 19, 10:25 UTCJul 19, 11:25 UTC1h 0m
2026-07-19 RPA4393 - Jul 19, 04:00 UTCJul 19, 05:15 UTC1h 15m
2026-07-19 RPA4393 MIA → CAE Jul 19, 03:57 UTCJul 19, 05:17 UTC1h 20m
2026-07-19 RPA4536 PHL → PIT Jul 19, 00:05 UTCJul 19, 02:55 UTC2h 50m
2026-07-18 RPA4341 DCA → SYR Jul 18, 20:25 UTCJul 18, 23:15 UTC2h 50m
2026-07-18 RPA4477 - Jul 18, 11:30 UTCJul 18, 12:50 UTC1h 20m
2026-07-18 RPA4598 LGA → DTW Jul 18, 01:04 UTCJul 18, 02:15 UTC1h 11m
2026-07-18 RPA4598 LGA → DTW Jul 18, 01:05 UTCJul 18, 02:29 UTC1h 25m
2026-07-17 RPA4421 - Jul 17, 22:25 UTCJul 17, 23:30 UTC1h 5m
2026-07-17 RPA4421 - Jul 17, 20:20 UTCJul 17, 21:30 UTC1h 10m
2026-07-17 RPA4601 - Jul 17, 16:59 UTCJul 17, 18:40 UTC1h 40m
2026-07-17 RPA4701 DCA → IND Jul 17, 13:55 UTCJul 17, 15:10 UTC1h 15m
2026-07-17 RPA4701 DCA → IND Jul 17, 13:54 UTCJul 17, 14:55 UTC1h 1m

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 N412YX page for operator, model, and routing details .

Mode-S A4DDCA frequently asked

What is Mode-S code A4DDCA?
A4DDCA is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N412YX.
Where is Mode-S A4DDCA registered?
Mode-S code A4DDCA 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 A4DDCA broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 22:30 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A4DDCA, octal 51156712, decimal 10,804,682.
What flights does A4DDCA operate?
Mode-S A4DDCA has broadcast 20 distinct callsigns, including RPA4393, RPA4729, RPA4606, RPA4396, RPA4725.