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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 1h ago
Flights observed
693
Distinct callsigns
20
Country
US
Last broadcast
1h ago

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
RPA4500 - 10 2026-07-12
RPA4378 Republic Airlines 10 2026-06-06
RPA4359 Republic Airlines 9 2026-06-09
RPA4728 - 8 2026-06-19
RPA4537 - 8 2026-07-11
RPA4712 Republic Airlines 7 2026-05-13
RPA4640 - 7 2026-07-13
RPA4599 Republic Airlines 7 2026-04-29
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
RPA4678 - 6 2026-07-04
RPA4676 Republic Airlines 6 2026-06-10
RPA4565 Republic Airlines 6 2026-06-07
RPA4535 Republic Airlines 6 2026-06-25
RPA4532 - 6 2026-06-28
RPA4501 - 6 2026-06-23
RPA4491 - 6 2026-07-03

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-14 RPA4692 - Jul 14, 00:45 UTCJul 14, 02:00 UTC1h 15m
2026-07-13 RPA4384 - Jul 13, 21:40 UTCJul 13, 23:40 UTC2h 0m
2026-07-13 RPA4384 ORD → BOS Jul 13, 21:37 UTCJul 13, 23:40 UTC2h 3m
2026-07-13 RPA4386 - Jul 13, 17:15 UTCJul 13, 19:15 UTC2h 0m
2026-07-13 RPA4708 - Jul 13, 15:55 UTCJul 13, 16:20 UTC25m
2026-07-13 RPA4708 - Jul 13, 13:50 UTCJul 13, 14:10 UTC20m
2026-07-13 RPA4714 - Jul 13, 11:20 UTCJul 13, 12:15 UTC55m
2026-07-13 RPA4714 MDT → BOS Jul 13, 11:17 UTCJul 13, 12:15 UTC58m
2026-07-13 RPA4640 - Jul 13, 05:05 UTCJul 13, 06:25 UTC1h 20m
2026-07-12 RPA4400 - Jul 12, 22:25 UTCJul 13, 00:25 UTC2h 0m
2026-07-12 RPA4400 - Jul 12, 19:30 UTCJul 12, 21:15 UTC1h 45m
2026-07-12 RPA4500 - Jul 12, 16:10 UTCJul 12, 17:50 UTC1h 40m
2026-07-12 RPA4500 - Jul 12, 13:20 UTCJul 12, 14:55 UTC1h 35m
2026-07-12 RPA4427 - Jul 12, 10:45 UTCJul 12, 11:55 UTC1h 10m
2026-07-12 RPA4427 PIT → ORD Jul 12, 10:41 UTCJul 12, 11:51 UTC1h 10m
2026-07-11 RPA4493 - Jul 11, 23:40 UTCJul 12, 00:35 UTC55m
2026-07-11 RPA4493 RDU → PIT Jul 11, 23:40 UTCJul 12, 00:35 UTC55m
2026-07-11 RPA4493 - Jul 11, 21:15 UTCJul 11, 22:05 UTC50m
2026-07-11 RPA4734 - Jul 11, 18:45 UTCJul 11, 19:50 UTC1h 5m
2026-07-11 RPA4568 - Jul 11, 16:35 UTCJul 11, 17:40 UTC1h 5m
2026-07-11 RPA4485 - Jul 11, 13:50 UTCJul 11, 14:50 UTC1h 0m
2026-07-11 RPA4485 ORD → PIT Jul 11, 13:47 UTCJul 11, 14:48 UTC1h 1m
2026-07-11 RPA4512 - Jul 11, 10:20 UTCJul 11, 12:15 UTC1h 55m
2026-07-11 RPA4511 - Jul 11, 02:30 UTCJul 11, 03:50 UTC1h 20m
2026-07-11 RPA4537 - Jul 11, 00:55 UTCJul 11, 01:20 UTC25m
2026-07-10 RPA4537 STL → ORD Jul 10, 23:55 UTCJul 11, 01:20 UTC1h 25m
2026-07-10 RPA4537 STL → ORD Jul 10, 23:55 UTCJul 11, 00:40 UTC45m
2026-07-10 RPA4537 - Jul 10, 22:00 UTCJul 10, 22:45 UTC45m
2026-07-10 RPA4720 - Jul 10, 19:35 UTCJul 10, 20:45 UTC1h 10m
2026-07-10 RPA4720 - Jul 10, 17:25 UTCJul 10, 18:10 UTC45m
2026-07-10 RPA4704 - Jul 10, 15:50 UTCJul 10, 16:15 UTC25m
2026-07-10 RPA4704 - Jul 10, 15:10 UTCJul 10, 16:15 UTC1h 5m
2026-07-10 RPA4704 SDF → ORD Jul 10, 15:09 UTCJul 10, 15:35 UTC26m
2026-07-10 RPA4704 - Jul 10, 13:25 UTCJul 10, 14:15 UTC50m
2026-07-10 RPA4519 - Jul 10, 10:10 UTCJul 10, 11:00 UTC50m
2026-07-10 RPA4442 ORD → DSM Jul 10, 04:10 UTCJul 10, 05:10 UTC1h 0m
2026-07-09 RPA4774 - Jul 9, 23:55 UTCJul 10, 02:05 UTC2h 10m
2026-07-09 RPA4774 - Jul 9, 20:55 UTCJul 9, 22:40 UTC1h 45m
2026-07-09 RPA4488 - Jul 9, 17:00 UTCJul 9, 19:15 UTC2h 15m
2026-07-09 RPA4488 PWM → ORD Jul 9, 16:55 UTCJul 9, 19:09 UTC2h 14m
2026-07-09 RPA4488 - Jul 9, 14:20 UTCJul 9, 16:05 UTC1h 45m
2026-07-09 RPA4597 - Jul 9, 12:35 UTCJul 9, 13:15 UTC40m
2026-07-09 RPA4597 IND → ORD Jul 9, 12:34 UTCJul 9, 13:14 UTC40m
2026-07-09 RPA4363 ORD → IND Jul 9, 04:45 UTCJul 9, 05:19 UTC34m
2026-07-09 RPA4363 ORD → IND Jul 9, 04:50 UTCJul 9, 05:20 UTC30m
2026-07-09 RPA4717 - Jul 9, 01:25 UTCJul 9, 03:00 UTC1h 35m
2026-07-08 RPA4717 ORD → BWI Jul 8, 23:05 UTCJul 9, 00:35 UTC1h 30m
2026-07-08 RPA4706 - Jul 8, 18:10 UTCJul 8, 20:10 UTC2h 0m
2026-07-08 RPA4706 YQB → ORD Jul 8, 18:07 UTCJul 8, 20:11 UTC2h 4m
2026-07-08 RPA4705 - Jul 8, 14:55 UTCJul 8, 16:55 UTC2h 0m

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 1h ago.
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 RPA4500, RPA4378, RPA4359, RPA4728, RPA4537.