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sensors Mode-S transponder

A53F5B

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N437YX · EMBRAER ERJ-170-200 (long wing) · operated by REPUBLIC AIRWAYS INC

Hex
A53F5B
Octal
51237533
Decimal
10,829,659
Country
US
Tail
N437YX
Type
E75L
Broadcasting now · callsign RPA4363 · 600 ft
Flights observed
642
Distinct callsigns
20
Country
US
Last broadcast
3h ago

Current position

A53F5B is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A53F5B 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
RPA4700 - 10 2026-07-06
RPA4375 - 10 2026-06-30
RPA4759 - 9 2026-07-12
RPA4738 - 9 2026-07-09
RPA4729 - 7 2026-07-14
RPA4428 Republic Airlines 7 2026-06-06
RPA4393 - 7 2026-06-22
RPA4343 Republic Airlines 7 2026-06-09
RPA4757 Republic Airlines 6 2026-05-07
RPA4756 Republic Airlines 6 2026-06-16
RPA4728 Republic Airlines 6 2026-06-08
RPA4647 - 6 2026-07-11
RPA4400 Republic Airlines 6 2026-06-18
RPA4399 - 6 2026-07-08
RPA4373 Republic Airlines 6 2026-05-02
RPA4360 Republic Airlines 6 2026-06-10
RPA4748 - 5 2026-06-26
RPA4746 - 5 2026-07-12
RPA4735 Republic Airlines 5 2026-06-17
RPA4720 Republic Airlines 5 2026-04-16

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-14 RPA4729 GRR → ORD Jul 14, 00:00 UTCJul 14, 00:45 UTC45m
2026-07-14 RPA4729 GRR → ORD Jul 14, 00:00 UTCJul 14, 00:34 UTC34m
2026-07-13 RPA4729 - Jul 13, 22:45 UTCJul 13, 23:15 UTC30m
2026-07-13 RPA4706 - Jul 13, 18:00 UTCJul 13, 20:00 UTC2h 0m
2026-07-13 RPA4706 YQB → ORD Jul 13, 17:58 UTCJul 13, 19:50 UTC1h 52m
2026-07-13 RPA4705 - Jul 13, 15:00 UTCJul 13, 16:55 UTC1h 55m
2026-07-13 RPA4683 ORF → ORD Jul 13, 11:25 UTCJul 13, 13:05 UTC1h 40m
2026-07-13 RPA4510 ORD → ORF Jul 13, 02:15 UTCJul 13, 04:10 UTC1h 55m
2026-07-13 RPA4510 ORD → ORF Jul 13, 02:16 UTCJul 13, 04:04 UTC1h 48m
2026-07-12 RPA4759 - Jul 12, 22:55 UTCJul 13, 00:50 UTC1h 55m
2026-07-12 RPA4759 ORD → ATL Jul 12, 20:20 UTCJul 12, 21:45 UTC1h 25m
2026-07-12 RPA4746 - Jul 12, 16:30 UTCJul 12, 18:10 UTC1h 40m
2026-07-12 RPA4746 MDT → ORD Jul 12, 16:29 UTCJul 12, 18:01 UTC1h 32m
2026-07-12 RPA4746 - Jul 12, 13:10 UTCJul 12, 14:30 UTC1h 20m
2026-07-12 RPA4659 - Jul 12, 09:50 UTCJul 12, 11:25 UTC1h 35m
2026-07-12 RPA4663 - Jul 12, 02:20 UTCJul 12, 03:45 UTC1h 25m
2026-07-11 RPA4621 - Jul 11, 22:01 UTCJul 12, 00:01 UTC2h 0m
2026-07-11 RPA4621 - Jul 11, 18:35 UTCJul 11, 20:40 UTC2h 5m
2026-07-11 RPA4647 - Jul 11, 16:55 UTCJul 11, 17:05 UTC10m
2026-07-11 RPA4647 - Jul 11, 15:45 UTCJul 11, 17:05 UTC1h 20m
2026-07-11 RPA4647 - Jul 11, 13:25 UTCJul 11, 14:40 UTC1h 15m
2026-07-11 RPA4597 - Jul 11, 10:50 UTCJul 11, 11:30 UTC40m
2026-07-10 RPA4637 - Jul 10, 23:50 UTCJul 11, 01:15 UTC1h 25m
2026-07-10 RPA4637 PHL → PHL Jul 10, 22:55 UTCJul 10, 23:10 UTC15m
2026-07-10 RPA4637 PHL → PHL Jul 10, 21:55 UTCJul 10, 22:00 UTC5m
2026-07-10 RPA4545 - Jul 10, 20:55 UTCJul 10, 21:50 UTC55m
2026-07-10 RPA4545 ACK → PHL Jul 10, 20:49 UTCJul 10, 21:47 UTC58m
2026-07-10 RPA4545 - Jul 10, 17:45 UTCJul 10, 18:35 UTC50m
2026-07-10 RPA4602 - Jul 10, 15:05 UTCJul 10, 16:05 UTC1h 0m
2026-07-10 RPA4602 MVY → PHL Jul 10, 15:01 UTCJul 10, 16:01 UTC1h 0m
2026-07-10 RPA4649 - Jul 10, 13:20 UTCJul 10, 14:20 UTC1h 0m
2026-07-10 RPA4626 - Jul 10, 10:20 UTCJul 10, 11:35 UTC1h 15m
2026-07-10 RPA4626 IND → DCA Jul 10, 10:18 UTCJul 10, 11:29 UTC1h 11m
2026-07-10 RPA4585 BOS → IND Jul 10, 04:30 UTCJul 10, 06:30 UTC2h 0m
2026-07-10 RPA4585 BOS → IND Jul 10, 04:26 UTCJul 10, 06:30 UTC2h 4m
2026-07-09 RPA4738 - Jul 9, 21:10 UTCJul 9, 22:50 UTC1h 40m
2026-07-09 RPA4738 ILM → BOS Jul 9, 21:03 UTCJul 9, 22:36 UTC1h 33m
2026-07-09 RPA4738 - Jul 9, 16:35 UTCJul 9, 18:05 UTC1h 30m
2026-07-09 RPA4635 - Jul 9, 14:45 UTCJul 9, 15:35 UTC50m
2026-07-09 RPA4635 SYR → BOS Jul 9, 14:42 UTCJul 9, 15:27 UTC45m
2026-07-09 RPA4635 - Jul 9, 12:40 UTCJul 9, 13:25 UTC45m
2026-07-09 RPA4642 - Jul 9, 10:05 UTCJul 9, 11:35 UTC1h 30m
2026-07-09 RPA4642 CMH → BOS Jul 9, 10:03 UTCJul 9, 11:32 UTC1h 29m
2026-07-08 RPA4641 BOS → CMH Jul 8, 23:05 UTCJul 9, 00:45 UTC1h 40m
2026-07-08 RPA4440 BUF → BOS Jul 8, 20:25 UTCJul 8, 21:30 UTC1h 5m
2026-07-08 RPA4440 BUF → BOS Jul 8, 20:25 UTCJul 8, 21:31 UTC1h 6m
2026-07-08 RPA4440 - Jul 8, 18:05 UTCJul 8, 19:10 UTC1h 5m
2026-07-08 RPA4399 - Jul 8, 15:05 UTCJul 8, 16:40 UTC1h 35m
2026-07-08 RPA4399 BNH → CMH Jul 8, 12:15 UTCJul 8, 13:55 UTC1h 40m
2026-07-08 RPA4806 ROC → BOS Jul 8, 10:10 UTCJul 8, 11:10 UTC1h 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 N437YX page for operator, model, and routing details .

Mode-S A53F5B frequently asked

What is Mode-S code A53F5B?
A53F5B is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N437YX.
Where is Mode-S A53F5B registered?
Mode-S code A53F5B 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 A53F5B broadcasting right now?
Yes. Mode-S A53F5B is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A53F5B, octal 51237533, decimal 10,829,659.
What flights does A53F5B operate?
Mode-S A53F5B has broadcast 20 distinct callsigns, including RPA4700, RPA4375, RPA4759, RPA4738, RPA4729.