Apparatus

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sensors Mode-S transponder

A53BA4

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N436YX · EMBRAER ERJ-170-200 (long wing) · operated by REPUBLIC AIRWAYS INC

Hex
A53BA4
Octal
51235644
Decimal
10,828,708
Country
US
Tail
N436YX
Type
E75L
No current signal · last broadcast Jul 26, 21:00 UTC
Flights observed
729
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 21:00 UTC

Last known position

Most recent position reported by Mode-S A53BA4.

Country allocation

The ICAO 24-bit address A53BA4 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
RPA4738 - 11 2026-06-20
RPA4606 - 11 2026-06-23
RPA4416 - 11 2026-07-16
RPA4421 Republic Airlines 9 2026-06-30
RPA4537 - 8 2026-07-02
RPA4373 Republic Airlines 8 2026-05-11
RPA4697 Republic Airlines 7 2026-07-22
RPA4678 - 7 2026-06-19
RPA4626 - 7 2026-07-16
RPA4599 Republic Airlines 7 2026-05-11
RPA4527 Republic Airlines 7 2026-05-13
RPA4430 Republic Airlines 7 2026-05-30
RPA4666 Republic Airlines 6 2026-07-23
RPA4596 Republic Airlines 6 2026-05-17
RPA4521 Republic Airlines 6 2026-04-24
RPA4452 Republic Airlines 6 2026-06-06
RPA4415 - 6 2026-06-26
RPA4359 - 6 2026-07-16
RPA4790 Republic Airlines 5 2026-05-05
RPA4755 Republic Airlines 5 2026-05-19

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 RPA4425 DCA → ALB Jul 26, 20:50 UTCJul 26, 21:00 UTC10m
2026-07-26 RPA4412 PHL → DTW Jul 26, 18:25 UTCJul 26, 19:30 UTC1h 5m
2026-07-26 RPA4609 ATL → LGA Jul 26, 15:25 UTCJul 26, 17:00 UTC1h 35m
2026-07-26 RPA4609 ATL → LGA Jul 26, 15:25 UTCJul 26, 16:58 UTC1h 33m
2026-07-26 RPA4587 XNA → LGA Jul 26, 13:05 UTCJul 26, 14:10 UTC1h 5m
2026-07-26 RPA4587 XNA → LGA Jul 26, 13:00 UTCJul 26, 14:04 UTC1h 4m
2026-07-25 RPA9928 BNA → IND Jul 25, 13:35 UTCJul 25, 14:45 UTC1h 10m
2026-07-24 RPA4366 DCA → MEM Jul 24, 16:35 UTCJul 24, 17:20 UTC45m
2026-07-24 RPA4635 ORD → LGA Jul 24, 14:50 UTCJul 24, 15:35 UTC45m
2026-07-24 RPA4635 ORD → LGA Jul 24, 14:44 UTCJul 24, 15:34 UTC50m
2026-07-24 RPA4635 ORD → LGA Jul 24, 12:45 UTCJul 24, 13:35 UTC50m
2026-07-24 RPA4642 DCA → PVD Jul 24, 10:20 UTCJul 24, 11:00 UTC40m
2026-07-24 RPA4642 DCA → PVD Jul 24, 10:15 UTCJul 24, 11:43 UTC1h 28m
2026-07-23 RPA4641 LGA → MSP Jul 23, 23:45 UTCJul 24, 01:25 UTC1h 40m
2026-07-23 RPA4440 PWM → DCA Jul 23, 20:40 UTCJul 23, 21:45 UTC1h 5m
2026-07-23 RPA4440 PWM → DCA Jul 23, 18:15 UTCJul 23, 19:25 UTC1h 10m
2026-07-23 RPA4440 PWM → DCA Jul 23, 18:14 UTCJul 23, 19:22 UTC1h 8m
2026-07-23 RPA4666 PIT → LGA Jul 23, 16:00 UTCJul 23, 17:20 UTC1h 20m
2026-07-23 RPA4666 PIT → LGA Jul 23, 14:04 UTCJul 23, 15:11 UTC1h 7m
2026-07-23 RPA4666 PIT → LGA Jul 23, 14:05 UTCJul 23, 15:15 UTC1h 10m
2026-07-23 RPA4788 LGA → OMA Jul 23, 11:25 UTCJul 23, 12:25 UTC1h 0m
2026-07-23 RPA4788 LGA → OMA Jul 23, 11:21 UTCJul 23, 12:18 UTC57m
2026-07-23 RPA4616 PHL → SDF Jul 23, 02:00 UTCJul 23, 03:10 UTC1h 10m
2026-07-22 RPA4374 LGA → BOS Jul 22, 23:54 UTCJul 23, 00:31 UTC37m
2026-07-22 RPA4374 LGA → BOS Jul 22, 23:55 UTCJul 23, 00:40 UTC45m
2026-07-22 RPA4697 BTV → DCA Jul 22, 21:00 UTCJul 22, 22:25 UTC1h 25m
2026-07-22 RPA4697 BTV → DCA Jul 22, 18:10 UTCJul 22, 19:55 UTC1h 45m
2026-07-22 RPA4550 YUL → LGA Jul 22, 15:10 UTCJul 22, 16:05 UTC55m
2026-07-22 RPA4550 YUL → LGA Jul 22, 15:09 UTCJul 22, 16:03 UTC54m
2026-07-22 RPA4550 YUL → LGA Jul 22, 13:20 UTCJul 22, 14:15 UTC55m
2026-07-22 RPA4424 PVD → DCA Jul 22, 11:10 UTCJul 22, 11:15 UTC5m
2026-07-21 RPA9943 JFK → CMH Jul 21, 22:35 UTCJul 22, 01:05 UTC2h 30m
2026-07-21 RPA9935 ORH → IND Jul 21, 10:40 UTCJul 21, 11:55 UTC1h 15m
2026-07-21 RPA4598 LGA → DTW Jul 21, 04:20 UTCJul 21, 05:40 UTC1h 20m
2026-07-20 RPA4607 ATL → LGA Jul 20, 23:50 UTCJul 21, 01:45 UTC1h 55m
2026-07-20 RPA4607 LGA → ATL Jul 20, 20:55 UTCJul 20, 22:35 UTC1h 40m
2026-07-20 RPA4375 BOS → LGA Jul 20, 18:20 UTCJul 20, 19:09 UTC49m
2026-07-20 RPA4375 BOS → LGA Jul 20, 18:20 UTCJul 20, 19:10 UTC50m
2026-07-20 RPA4375 LGA → BOS Jul 20, 16:30 UTCJul 20, 17:05 UTC35m
2026-07-20 RPA4491 DCA → LGA Jul 20, 14:10 UTCJul 20, 14:55 UTC45m
2026-07-20 RPA4339 ORD → DCA Jul 20, 11:20 UTCJul 20, 12:50 UTC1h 30m
2026-07-19 RPA4774 - Jul 19, 23:30 UTCJul 20, 02:05 UTC2h 35m
2026-07-19 RPA4774 - Jul 19, 20:40 UTCJul 19, 22:30 UTC1h 50m
2026-07-19 RPA4409 - Jul 19, 18:35 UTCJul 19, 19:00 UTC25m
2026-07-19 RPA4409 - Jul 19, 17:10 UTCJul 19, 17:30 UTC20m
2026-07-19 RPA4625 - Jul 19, 12:10 UTCJul 19, 13:20 UTC1h 10m
2026-07-17 RPA4539 - Jul 17, 03:45 UTCJul 17, 04:44 UTC1h 0m
2026-07-17 RPA4457 - Jul 17, 00:50 UTCJul 17, 02:15 UTC1h 25m
2026-07-17 RPA4457 MEM → ORD Jul 17, 00:47 UTCJul 17, 02:05 UTC1h 18m
2026-07-16 RPA4460 - Jul 16, 22:19 UTCJul 17, 00:04 UTC1h 45m

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 N436YX page for operator, model, and routing details .

Mode-S A53BA4 frequently asked

What is Mode-S code A53BA4?
A53BA4 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N436YX.
Where is Mode-S A53BA4 registered?
Mode-S code A53BA4 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 A53BA4 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 21:00 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A53BA4, octal 51235644, decimal 10,828,708.
What flights does A53BA4 operate?
Mode-S A53BA4 has broadcast 20 distinct callsigns, including RPA4738, RPA4606, RPA4416, RPA4421, RPA4537.