Apparatus

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sensors Mode-S transponder

A50900

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N423YX · EMBRAER ERJ-170-200 (long wing) · operated by REPUBLIC AIRWAYS INC

Hex
A50900
Octal
51204400
Decimal
10,815,744
Country
US
Tail
N423YX
Type
E75L
No current signal · last broadcast Jul 26, 21:50 UTC
Flights observed
778
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 21:50 UTC

Last known position

Most recent position reported by Mode-S A50900.

Country allocation

The ICAO 24-bit address A50900 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
RPA4565 Republic Airlines 11 2026-07-17
RPA4500 - 10 2026-07-12
RPA4378 Republic Airlines 10 2026-06-06
RPA4364 Republic Airlines 9 2026-07-22
RPA4359 Republic Airlines 9 2026-06-09
RPA4728 - 8 2026-06-19
RPA4678 - 8 2026-07-18
RPA4537 - 8 2026-07-11
RPA4370 Republic Airlines 8 2026-07-25
RPA4759 Republic Airlines 7 2026-07-20
RPA4712 Republic Airlines 7 2026-05-13
RPA4640 - 7 2026-07-13
RPA4630 Republic Airlines 7 2026-07-22
RPA4599 Republic Airlines 7 2026-04-29
RPA4428 Republic Airlines 7 2026-07-25
RPA4384 - 7 2026-07-13
RPA4380 - 7 2026-07-02
RPA4768 Republic Airlines 6 2026-06-08
RPA4765 Republic Airlines 6 2026-05-25
RPA4738 Republic Airlines 6 2026-06-08

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 RPA4697 BTV → DCA Jul 26, 20:20 UTCJul 26, 21:45 UTC1h 25m
2026-07-26 RPA4697 BTV → DCA Jul 26, 17:45 UTCJul 26, 19:10 UTC1h 25m
2026-07-26 RPA4550 YUL → LGA Jul 26, 15:10 UTCJul 26, 16:05 UTC55m
2026-07-26 RPA4550 YUL → LGA Jul 26, 12:45 UTCJul 26, 13:40 UTC55m
2026-07-25 RPA4632 LGA → ORD Jul 25, 20:40 UTCJul 25, 21:30 UTC50m
2026-07-25 RPA4370 PHL → BNA Jul 25, 19:35 UTCJul 25, 19:40 UTC5m
2026-07-25 RPA4370 PHL → BNA Jul 25, 19:04 UTCJul 25, 19:20 UTC16m
2026-07-25 RPA4370 PHL → BNA Jul 25, 19:05 UTCJul 25, 19:40 UTC35m
2026-07-25 RPA4428 LGA → LIT Jul 25, 16:55 UTCJul 25, 18:00 UTC1h 5m
2026-07-25 RPA4428 LGA → LIT Jul 25, 16:43 UTCJul 25, 17:57 UTC1h 14m
2026-07-25 RPA4428 LGA → LIT Jul 25, 14:15 UTCJul 25, 15:25 UTC1h 10m
2026-07-25 RPA4682 ILM → LGA Jul 25, 11:30 UTCJul 25, 12:35 UTC1h 5m
2026-07-25 RPA4682 ILM → LGA Jul 25, 11:19 UTCJul 25, 12:33 UTC1h 14m
2026-07-25 RPA4792 LGA → ILM Jul 25, 00:05 UTCJul 25, 01:10 UTC1h 5m
2026-07-24 RPA4617 SDF → PHL Jul 24, 21:30 UTCJul 24, 22:50 UTC1h 20m
2026-07-24 RPA4617 SDF → PHL Jul 24, 21:26 UTCJul 24, 22:44 UTC1h 18m
2026-07-24 RPA4767 JFK → CMH Jul 24, 19:00 UTCJul 24, 20:20 UTC1h 20m
2026-07-24 RPA4767 JFK → CMH Jul 24, 18:58 UTCJul 24, 20:01 UTC1h 3m
2026-07-24 RPA4408 YYZ → ORD Jul 24, 16:00 UTCJul 24, 17:35 UTC1h 35m
2026-07-24 RPA4408 YYZ → ORD Jul 24, 13:25 UTCJul 24, 14:55 UTC1h 30m
2026-07-24 RPA4657 CVG → JFK Jul 24, 10:15 UTCJul 24, 11:55 UTC1h 40m
2026-07-24 RPA4657 CVG → JFK Jul 24, 10:14 UTCJul 24, 11:50 UTC1h 36m
2026-07-24 RPA4776 JFK → BOS Jul 24, 03:25 UTCJul 24, 04:10 UTC45m
2026-07-24 RPA4492 DCA → BDL Jul 24, 00:15 UTCJul 24, 02:00 UTC1h 45m
2026-07-23 RPA4436 PHL → BOS Jul 23, 21:45 UTCJul 23, 23:00 UTC1h 15m
2026-07-23 RPA4436 PHL → BOS Jul 23, 21:44 UTCJul 23, 22:58 UTC1h 14m
2026-07-23 RPA4428 LGA → LIT Jul 23, 16:25 UTCJul 23, 18:40 UTC2h 15m
2026-07-23 RPA4428 LGA → LIT Jul 23, 13:05 UTCJul 23, 15:10 UTC2h 5m
2026-07-23 RPA4682 ILM → LGA Jul 23, 10:40 UTCJul 23, 11:45 UTC1h 5m
2026-07-23 RPA4792 LGA → ILM Jul 23, 00:35 UTCJul 23, 01:50 UTC1h 15m
2026-07-22 RPA4630 DCA → LGA Jul 22, 21:55 UTCJul 22, 23:10 UTC1h 15m
2026-07-22 RPA4630 DCA → LGA Jul 22, 21:53 UTCJul 22, 22:59 UTC1h 6m
2026-07-22 RPA4630 DCA → LGA Jul 22, 19:40 UTCJul 22, 21:00 UTC1h 20m
2026-07-22 RPA4364 MSP → PHL Jul 22, 16:35 UTCJul 22, 18:25 UTC1h 50m
2026-07-22 RPA4364 MSP → PHL Jul 22, 16:31 UTCJul 22, 18:23 UTC1h 52m
2026-07-22 RPA4364 MSP → PHL Jul 22, 13:30 UTCJul 22, 15:30 UTC2h 0m
2026-07-21 RPA9935 ORH → IND Jul 21, 18:45 UTCJul 21, 20:05 UTC1h 20m
2026-07-21 RPA4635 ORD → LGA Jul 21, 15:15 UTCJul 21, 16:00 UTC45m
2026-07-21 RPA4635 ORD → LGA Jul 21, 15:09 UTCJul 21, 15:41 UTC32m
2026-07-21 RPA4635 ORD → LGA Jul 21, 13:25 UTCJul 21, 14:10 UTC45m
2026-07-21 RPA4642 - Jul 21, 10:10 UTCJul 21, 11:35 UTC1h 25m
2026-07-21 RPA4642 CMH → BOS Jul 21, 10:08 UTCJul 21, 11:32 UTC1h 24m
2026-07-21 RPA4337 PHL → ATL Jul 21, 00:00 UTCJul 21, 00:50 UTC50m
2026-07-20 RPA4759 ORD → TVC Jul 20, 19:55 UTCJul 20, 21:35 UTC1h 40m
2026-07-20 RPA4759 ORD → TVC Jul 20, 19:53 UTCJul 20, 21:34 UTC1h 41m
2026-07-20 RPA4759 ORD → TVC Jul 20, 17:15 UTCJul 20, 18:40 UTC1h 25m
2026-07-20 RPA4723 - Jul 20, 14:30 UTCJul 20, 15:55 UTC1h 25m
2026-07-20 RPA9938 BOS → DCA Jul 20, 03:00 UTCJul 20, 04:10 UTC1h 10m
2026-07-19 RPA4759 ORD → TVC Jul 19, 21:35 UTCJul 19, 23:10 UTC1h 35m
2026-07-19 RPA4365 AVL → LGA Jul 19, 14:35 UTCJul 19, 16:40 UTC2h 5m

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 N423YX page for operator, model, and routing details .

Mode-S A50900 frequently asked

What is Mode-S code A50900?
A50900 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N423YX.
Where is Mode-S A50900 registered?
Mode-S code A50900 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 A50900 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 21:50 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A50900, octal 51204400, decimal 10,815,744.
What flights does A50900 operate?
Mode-S A50900 has broadcast 20 distinct callsigns, including RPA4565, RPA4500, RPA4378, RPA4364, RPA4359.