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sensors Mode-S transponder

A645B4

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N503GJ · BOMBARDIER Regional Jet CRJ-700 · operated by BANK OF UTAH TRUSTEE

Hex
A645B4
Octal
51442664
Decimal
10,896,820
Country
US
Tail
N503GJ
Type
CRJ7
No current signal · last broadcast 23h ago
Flights observed
637
Distinct callsigns
20
Country
US
Last broadcast
23h ago

Last known position

Most recent position reported by Mode-S A645B4.

Country allocation

The ICAO 24-bit address A645B4 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
GJS4482 - 14 2026-06-24
GJS4190 - 12 2026-06-24
GJS4480 GoJet Airlines 10 2026-06-16
GJS4439 - 10 2026-06-23
GJS4472 - 9 2026-07-10
GJS4176 - 9 2026-07-10
GJS4582 GoJet Airlines 8 2026-06-20
GJS4400 - 8 2026-06-29
GJS4188 - 8 2026-07-03
GJS4603 - 7 2026-07-12
GJS4495 GoJet Airlines 7 2026-06-10
GJS4429 - 7 2026-06-20
GJS4191 GoJet Airlines 7 2026-06-07
GJS4498 GoJet Airlines 6 2026-05-15
GJS4430 - 6 2026-07-08
GJS4428 - 6 2026-07-07
GJS4387 GoJet Airlines 6 2026-05-26
GJS4171 - 6 2026-06-28
GJS4598 GoJet Airlines 5 2026-05-11
GJS4591 - 5 2026-06-18

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-13 GJS4576 ORD → STL Jul 13, 03:40 UTCJul 13, 04:15 UTC35m
2026-07-13 GJS4576 ORD → STL Jul 13, 03:30 UTCJul 13, 04:15 UTC45m
2026-07-12 GJS4175 - Jul 12, 21:55 UTCJul 12, 23:45 UTC1h 50m
2026-07-12 GJS4461 - Jul 12, 19:15 UTCJul 12, 20:45 UTC1h 30m
2026-07-12 GJS4461 ORD → ABE Jul 12, 19:26 UTCJul 12, 20:45 UTC1h 19m
2026-07-12 GJS4595 - Jul 12, 16:05 UTCJul 12, 17:05 UTC1h 0m
2026-07-12 GJS4611 - Jul 12, 14:01 UTCJul 12, 14:40 UTC40m
2026-07-12 GJS4440 - Jul 12, 11:35 UTCJul 12, 12:05 UTC30m
2026-07-12 GJS4440 PIA → ORD Jul 12, 11:50 UTCJul 12, 11:54 UTC4m
2026-07-12 GJS4603 - Jul 12, 04:50 UTCJul 12, 05:20 UTC30m
2026-07-12 GJS4603 ORD → PIA Jul 12, 03:30 UTCJul 12, 05:19 UTC1h 49m
2026-07-11 GJS4434 - Jul 11, 23:10 UTCJul 12, 00:40 UTC1h 30m
2026-07-11 GJS4434 CHA → ORD Jul 11, 23:23 UTCJul 12, 00:23 UTC1h 0m
2026-07-11 GJS4419 EWR → CHA Jul 11, 19:35 UTCJul 11, 21:20 UTC1h 45m
2026-07-11 GJS4514 - Jul 11, 03:05 UTCJul 11, 04:15 UTC1h 10m
2026-07-10 GJS4509 - Jul 10, 22:35 UTCJul 11, 00:00 UTC1h 25m
2026-07-10 GJS4509 EWR → GSO Jul 10, 22:28 UTCJul 10, 23:59 UTC1h 31m
2026-07-10 GJS4560 DCA → EWR Jul 10, 19:45 UTCJul 10, 20:25 UTC40m
2026-07-10 GJS4472 EWR → DCA Jul 10, 17:20 UTCJul 10, 18:00 UTC40m
2026-07-10 GJS4472 EWR → DCA Jul 10, 17:22 UTCJul 10, 17:59 UTC37m
2026-07-10 GJS4493 RIC → EWR Jul 10, 14:40 UTCJul 10, 15:50 UTC1h 10m
2026-07-10 GJS4493 RIC → EWR Jul 10, 14:45 UTCJul 10, 15:50 UTC1h 5m
2026-07-10 GJS4176 - Jul 10, 00:35 UTCJul 10, 01:30 UTC55m
2026-07-09 GJS4176 EWR → RIC Jul 9, 23:58 UTCJul 10, 01:29 UTC1h 31m
2026-07-09 GJS4184 - Jul 9, 16:30 UTCJul 9, 17:30 UTC1h 0m
2026-07-09 GJS4184 DCA → EWR Jul 9, 16:00 UTCJul 9, 17:22 UTC1h 22m
2026-07-09 GJS4446 - Jul 9, 14:25 UTCJul 9, 15:15 UTC50m
2026-07-09 GJS4167 DCA → EWR Jul 9, 11:45 UTCJul 9, 12:45 UTC1h 0m
2026-07-09 GJS4167 DCA → EWR Jul 9, 11:32 UTCJul 9, 12:41 UTC1h 9m
2026-07-09 GJS4457 EWR → DCA Jul 9, 00:55 UTCJul 9, 01:35 UTC40m
2026-07-08 GJS4511 - Jul 8, 21:15 UTCJul 8, 22:45 UTC1h 30m
2026-07-08 GJS4430 - Jul 8, 18:10 UTCJul 8, 19:30 UTC1h 20m
2026-07-08 GJS4430 EWR → AVL Jul 8, 18:11 UTCJul 8, 19:36 UTC1h 25m
2026-07-08 GJS4403 - Jul 8, 15:35 UTCJul 8, 16:35 UTC1h 0m
2026-07-08 GJS4390 EWR → PIT Jul 8, 13:45 UTCJul 8, 14:23 UTC38m
2026-07-08 GJS4390 - Jul 8, 13:30 UTCJul 8, 14:20 UTC50m
2026-07-08 GJS4604 - Jul 8, 11:00 UTCJul 8, 11:45 UTC45m
2026-07-08 GJS4473 - Jul 8, 02:25 UTCJul 8, 02:50 UTC25m
2026-07-07 GJS4455 - Jul 7, 23:55 UTCJul 8, 01:15 UTC1h 20m
2026-07-07 GJS4418 - Jul 7, 22:00 UTCJul 7, 23:05 UTC1h 5m
2026-07-07 GJS4549 - Jul 7, 19:05 UTCJul 7, 19:30 UTC25m
2026-07-07 GJS4535 - Jul 7, 17:35 UTCJul 7, 18:05 UTC30m
2026-07-07 GJS4535 IAD → RIC Jul 7, 17:20 UTCJul 7, 18:08 UTC48m
2026-07-07 GJS4609 - Jul 7, 14:45 UTCJul 7, 16:00 UTC1h 15m
2026-07-07 GJS4609 PVD → IAD Jul 7, 14:38 UTCJul 7, 15:57 UTC1h 19m
2026-07-07 GJS4599 - Jul 7, 12:50 UTCJul 7, 13:45 UTC55m
2026-07-07 GJS4428 - Jul 7, 10:10 UTCJul 7, 11:05 UTC55m
2026-07-07 GJS4414 IAD → CMH Jul 7, 05:05 UTCJul 7, 05:55 UTC50m
2026-07-06 GJS4505 - Jul 6, 19:10 UTCJul 6, 20:10 UTC1h 0m
2026-07-06 GJS4505 SYR → IAD Jul 6, 18:53 UTCJul 6, 20:06 UTC1h 13m

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 N503GJ page for operator, model, and routing details .

Mode-S A645B4 frequently asked

What is Mode-S code A645B4?
A645B4 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N503GJ.
Where is Mode-S A645B4 registered?
Mode-S code A645B4 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 A645B4 broadcasting right now?
No active broadcast right now. Last signal was 23h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A645B4, octal 51442664, decimal 10,896,820.
What flights does A645B4 operate?
Mode-S A645B4 has broadcast 20 distinct callsigns, including GJS4482, GJS4190, GJS4480, GJS4439, GJS4472.