Apparatus

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sensors Mode-S transponder

A4E181

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N413YX · EMBRAER ERJ-170-200 (long wing) · operated by REPUBLIC AIRWAYS INC

Hex
A4E181
Octal
51160601
Decimal
10,805,633
Country
US
Tail
N413YX
Type
E75L
No current signal · last broadcast Jul 26, 21:35 UTC
Flights observed
741
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 21:35 UTC

Last known position

Most recent position reported by Mode-S A4E181.

Country allocation

The ICAO 24-bit address A4E181 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
RPA4781 - 11 2026-07-07
RPA4426 Republic Airlines 10 2026-06-03
RPA4431 Republic Airlines 9 2026-07-25
RPA4373 - 9 2026-07-06
RPA4627 - 8 2026-06-22
RPA4501 Republic Airlines 8 2026-07-19
RPA4478 Republic Airlines 8 2026-06-03
RPA4745 Republic Airlines 7 2026-06-13
RPA4752 Republic Airlines 6 2026-05-30
RPA4747 - 6 2026-06-26
RPA4738 Republic Airlines 6 2026-06-15
RPA4727 Republic Airlines 6 2026-06-21
RPA4710 Republic Airlines 6 2026-07-24
RPA4685 - 6 2026-07-20
RPA4635 - 6 2026-07-11
RPA4607 - 6 2026-07-02
RPA4599 Republic Airlines 6 2026-04-28
RPA4537 Republic Airlines 6 2026-06-12
RPA4336 - 6 2026-06-17
RPA4773 - 5 2026-06-25

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 RPA4378 BOS → JFK Jul 26, 20:45 UTCJul 26, 21:35 UTC50m
2026-07-26 RPA4620 LGA → RIC Jul 26, 15:45 UTCJul 26, 18:15 UTC2h 30m
2026-07-26 RPA4620 LGA → RIC Jul 26, 11:55 UTCJul 26, 14:25 UTC2h 30m
2026-07-26 RPA4702 GSP → PHL Jul 26, 00:15 UTCJul 26, 01:00 UTC45m
2026-07-25 RPA4553 LGA → DTW Jul 25, 21:35 UTCJul 25, 22:45 UTC1h 10m
2026-07-25 RPA4553 LGA → DTW Jul 25, 21:29 UTCJul 25, 22:42 UTC1h 13m
2026-07-25 RPA4553 LGA → DTW Jul 25, 19:45 UTCJul 25, 20:40 UTC55m
2026-07-25 RPA4431 JFK → CMH Jul 25, 16:20 UTCJul 25, 18:25 UTC2h 5m
2026-07-25 RPA4431 JFK → CMH Jul 25, 13:25 UTCJul 25, 15:25 UTC2h 0m
2026-07-24 RPA4495 PHL → DCA Jul 24, 22:00 UTCJul 24, 23:15 UTC1h 15m
2026-07-24 RPA4495 PHL → DCA Jul 24, 21:57 UTCJul 24, 23:13 UTC1h 16m
2026-07-24 RPA4710 PHL → DCA Jul 24, 19:05 UTCJul 24, 20:55 UTC1h 50m
2026-07-24 RPA4710 PHL → DCA Jul 24, 19:03 UTCJul 24, 20:55 UTC1h 52m
2026-07-24 RPA4765 JFK → CLE Jul 24, 16:35 UTCJul 24, 17:50 UTC1h 15m
2026-07-24 RPA4354 PHL → SDF Jul 24, 13:45 UTCJul 24, 15:20 UTC1h 35m
2026-07-24 RPA4597 CMH → BOS Jul 24, 10:53 UTCJul 24, 11:30 UTC37m
2026-07-23 RPA4585 BOS → IND Jul 23, 22:40 UTCJul 24, 00:40 UTC2h 0m
2026-07-23 RPA4370 PHL → BNA Jul 23, 20:51 UTCJul 23, 21:25 UTC34m
2026-07-23 RPA4370 PHL → BNA Jul 23, 20:55 UTCJul 23, 21:30 UTC35m
2026-07-23 RPA4347 ORD → CLE Jul 23, 15:05 UTCJul 23, 16:15 UTC1h 10m
2026-07-23 RPA4347 ORD → CLE Jul 23, 12:45 UTCJul 23, 13:45 UTC1h 0m
2026-07-23 RPA9929 JFK → DCA Jul 23, 09:55 UTCJul 23, 10:45 UTC50m
2026-07-22 RPA4493 LGA → BNA Jul 22, 23:45 UTCJul 23, 00:40 UTC55m
2026-07-22 RPA4493 LGA → BNA Jul 22, 21:55 UTCJul 22, 23:00 UTC1h 5m
2026-07-22 RPA4796 BHM → DCA Jul 22, 20:15 UTCJul 22, 20:55 UTC40m
2026-07-22 RPA4590 LGA → DCA Jul 22, 18:27 UTCJul 22, 19:15 UTC48m
2026-07-22 RPA4590 LGA → DCA Jul 22, 18:30 UTCJul 22, 19:15 UTC45m
2026-07-22 RPA4669 MIA → BTV Jul 22, 14:55 UTCJul 22, 16:50 UTC1h 55m
2026-07-22 RPA4669 MIA → BTV Jul 22, 14:54 UTCJul 22, 16:49 UTC1h 55m
2026-07-21 RPA9933 PHL → ATL Jul 21, 23:20 UTCJul 22, 00:10 UTC50m
2026-07-21 RPA9939 BUF → CMH Jul 21, 20:30 UTCJul 21, 22:25 UTC1h 55m
2026-07-21 RPA9938 BOS → DCA Jul 21, 14:55 UTCJul 21, 15:55 UTC1h 0m
2026-07-21 RPA4733 CMH → BOS Jul 21, 00:50 UTCJul 21, 02:15 UTC1h 25m
2026-07-20 RPA4733 CMH → BOS Jul 20, 22:10 UTCJul 20, 23:30 UTC1h 20m
2026-07-20 RPA4685 LGA → DCA Jul 20, 20:00 UTCJul 20, 20:45 UTC45m
2026-07-20 RPA4496 LGA → BUF Jul 20, 16:55 UTCJul 20, 18:00 UTC1h 5m
2026-07-20 RPA4496 LGA → BUF Jul 20, 14:40 UTCJul 20, 15:55 UTC1h 15m
2026-07-20 RPA4604 CMH → LGA Jul 20, 11:45 UTCJul 20, 12:55 UTC1h 10m
2026-07-20 RPA4604 CMH → LGA Jul 20, 11:41 UTCJul 20, 12:57 UTC1h 16m
2026-07-19 RPA4462 LGA → CMH Jul 19, 21:55 UTCJul 19, 23:19 UTC1h 24m
2026-07-19 RPA4462 LGA → CMH Jul 19, 21:55 UTCJul 19, 23:20 UTC1h 25m
2026-07-19 RPA4501 IND → DCA Jul 19, 19:10 UTCJul 19, 19:55 UTC45m
2026-07-19 RPA4501 IND → DCA Jul 19, 19:09 UTCJul 19, 19:54 UTC45m
2026-07-19 RPA4501 IND → DCA Jul 19, 16:40 UTCJul 19, 17:35 UTC55m
2026-07-19 RPA4491 - Jul 19, 15:00 UTCJul 19, 15:35 UTC35m
2026-07-19 RPA4491 LGA → DCA Jul 19, 13:05 UTCJul 19, 13:55 UTC50m
2026-07-18 RPA4675 - Jul 18, 12:25 UTCJul 18, 14:25 UTC2h 0m
2026-07-18 RPA4674 BOS → TVC Jul 18, 01:10 UTCJul 18, 03:05 UTC1h 56m
2026-07-17 RPA4475 - Jul 17, 20:15 UTCJul 17, 22:29 UTC2h 15m
2026-07-17 RPA4475 LGA → PBI Jul 17, 16:59 UTCJul 17, 19:25 UTC2h 25m

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 N413YX page for operator, model, and routing details .

Mode-S A4E181 frequently asked

What is Mode-S code A4E181?
A4E181 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N413YX.
Where is Mode-S A4E181 registered?
Mode-S code A4E181 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 A4E181 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 21:35 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A4E181, octal 51160601, decimal 10,805,633.
What flights does A4E181 operate?
Mode-S A4E181 has broadcast 20 distinct callsigns, including RPA4781, RPA4426, RPA4431, RPA4373, RPA4627.