Apparatus

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sensors Mode-S transponder

A6DFF9

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N542GJ · BOMBARDIER Regional Jet CRJ-700 · operated by SKYWEST AIRLINES INC

Hex
A6DFF9
Octal
51557771
Decimal
10,936,313
Country
US
Tail
N542GJ
Type
CRJ7
Broadcasting now · callsign GJS4407 · 26,100 ft
Flights observed
635
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 22:15 UTC

Current position

A6DFF9 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A6DFF9 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
GJS4385 GoJet Airlines 13 2026-07-26
GJS4603 - 9 2026-06-27
GJS4586 GoJet Airlines 9 2026-07-25
GJS4442 GoJet Airlines 9 2026-07-25
GJS4446 GoJet Airlines 8 2026-07-26
GJS4605 - 7 2026-07-12
GJS4388 - 7 2026-06-27
GJS4191 GoJet Airlines 7 2026-07-26
GJS4187 - 7 2026-07-09
GJS4184 GoJet Airlines 7 2026-07-26
GJS4601 - 6 2026-06-30
GJS4600 - 6 2026-07-15
GJS4574 GoJet Airlines 6 2026-07-16
GJS4507 - 6 2026-07-19
GJS4437 GoJet Airlines 6 2026-07-22
GJS4410 - 6 2026-06-18
GJS4389 - 6 2026-07-02
GJS4592 - 5 2026-07-11
GJS4580 GoJet Airlines 5 2026-06-02
GJS4546 - 5 2026-06-27

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 GJS4448 IAD → SDF Jul 26, 22:00 UTCJul 26, 22:15 UTC15m
2026-07-26 GJS4608 ROA → ORD Jul 26, 18:45 UTCJul 26, 20:05 UTC1h 20m
2026-07-26 GJS4489 EWR → DCA Jul 26, 16:30 UTCJul 26, 17:35 UTC1h 5m
2026-07-26 GJS4184 EWR → DCA Jul 26, 14:35 UTCJul 26, 15:15 UTC40m
2026-07-26 GJS4446 DCA → EWR Jul 26, 12:45 UTCJul 26, 13:30 UTC45m
2026-07-26 GJS4191 RIC → EWR Jul 26, 10:05 UTCJul 26, 11:00 UTC55m
2026-07-26 GJS4385 EWR → ROC Jul 26, 03:10 UTCJul 26, 04:00 UTC50m
2026-07-26 GJS4385 EWR → ROC Jul 26, 01:35 UTCJul 26, 02:20 UTC45m
2026-07-25 GJS4586 ORD → ICT Jul 25, 21:05 UTCJul 25, 21:50 UTC45m
2026-07-25 GJS4442 DCA → EWR Jul 25, 17:20 UTCJul 25, 18:00 UTC40m
2026-07-25 GJS4172 DCA → EWR Jul 25, 15:22 UTCJul 25, 16:30 UTC1h 8m
2026-07-25 GJS4172 DCA → EWR Jul 25, 15:20 UTCJul 25, 16:15 UTC55m
2026-07-25 GJS4489 EWR → DCA Jul 25, 12:50 UTCJul 25, 13:50 UTC1h 0m
2026-07-25 GJS4489 EWR → DCA Jul 25, 12:52 UTCJul 25, 13:43 UTC51m
2026-07-25 GJS4497 ORD → XNA Jul 25, 10:55 UTCJul 25, 11:35 UTC40m
2026-07-24 GJS4385 EWR → ROC Jul 24, 23:20 UTCJul 25, 00:05 UTC45m
2026-07-24 GJS4385 EWR → ROC Jul 24, 23:25 UTCJul 25, 00:04 UTC39m
2026-07-24 GJS4586 ORD → ICT Jul 24, 21:10 UTCJul 24, 21:50 UTC40m
2026-07-24 GJS4608 ROA → ORD Jul 24, 18:50 UTCJul 24, 19:55 UTC1h 5m
2026-07-24 GJS4489 EWR → DCA Jul 24, 16:20 UTCJul 24, 17:30 UTC1h 10m
2026-07-24 GJS4184 EWR → DCA Jul 24, 14:20 UTCJul 24, 15:00 UTC40m
2026-07-24 GJS4446 DCA → EWR Jul 24, 12:40 UTCJul 24, 13:25 UTC45m
2026-07-24 GJS4167 RIC → EWR Jul 24, 10:10 UTCJul 24, 10:45 UTC35m
2026-07-24 GJS4457 ORD → STL Jul 24, 01:05 UTCJul 24, 01:45 UTC40m
2026-07-23 GJS4180 DCA → EWR Jul 23, 22:25 UTCJul 23, 23:05 UTC40m
2026-07-23 GJS4486 RIC → EWR Jul 23, 20:25 UTCJul 23, 21:15 UTC50m
2026-07-23 GJS4442 DCA → EWR Jul 23, 17:15 UTCJul 23, 17:55 UTC40m
2026-07-23 GJS4442 DCA → EWR Jul 23, 17:15 UTCJul 23, 17:52 UTC37m
2026-07-23 GJS4172 DCA → EWR Jul 23, 15:25 UTCJul 23, 16:10 UTC45m
2026-07-23 GJS4399 CVG → EWR Jul 23, 12:30 UTCJul 23, 13:50 UTC1h 20m
2026-07-23 GJS4405 EWR → DTW Jul 23, 01:35 UTCJul 23, 03:00 UTC1h 25m
2026-07-23 GJS4405 EWR → DTW Jul 23, 01:43 UTCJul 23, 03:02 UTC1h 19m
2026-07-22 GJS4180 DCA → EWR Jul 22, 22:35 UTCJul 22, 23:30 UTC55m
2026-07-22 GJS4180 DCA → EWR Jul 22, 22:21 UTCJul 22, 23:23 UTC1h 2m
2026-07-22 GJS4486 RIC → EWR Jul 22, 20:15 UTCJul 22, 21:00 UTC45m
2026-07-22 GJS4442 DCA → EWR Jul 22, 17:10 UTCJul 22, 17:55 UTC45m
2026-07-22 GJS4172 DCA → EWR Jul 22, 15:30 UTCJul 22, 16:10 UTC40m
2026-07-22 GJS4430 DCA → EWR Jul 22, 13:00 UTCJul 22, 13:45 UTC45m
2026-07-22 GJS4437 EWR → PHL Jul 22, 11:10 UTCJul 22, 11:40 UTC30m
2026-07-20 GJS4401 EWR → PVD Jul 20, 20:55 UTCJul 20, 21:40 UTC45m
2026-07-20 GJS4433 EWR → DCA Jul 20, 18:30 UTCJul 20, 19:10 UTC40m
2026-07-20 GJS4607 TVC → ORD Jul 20, 15:25 UTCJul 20, 16:50 UTC1h 25m
2026-07-20 GJS4528 ORD → CAE Jul 20, 12:44 UTCJul 20, 13:48 UTC1h 4m
2026-07-20 GJS4528 - Jul 20, 12:25 UTCJul 20, 13:45 UTC1h 20m
2026-07-20 GJS4415 DAY → ORD Jul 20, 09:55 UTCJul 20, 10:50 UTC55m
2026-07-20 GJS4415 DAY → ORD Jul 20, 10:03 UTCJul 20, 10:40 UTC37m
2026-07-20 GJS4484 - Jul 20, 01:30 UTCJul 20, 02:15 UTC45m
2026-07-19 GJS4409 - Jul 19, 23:40 UTCJul 20, 00:35 UTC55m
2026-07-19 GJS4554 - Jul 19, 22:20 UTCJul 19, 22:50 UTC30m
2026-07-19 GJS4429 CVG → IAD Jul 19, 19:40 UTCJul 19, 20:05 UTC25m

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 N542GJ page for operator, model, and routing details .

Mode-S A6DFF9 frequently asked

What is Mode-S code A6DFF9?
A6DFF9 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N542GJ.
Where is Mode-S A6DFF9 registered?
Mode-S code A6DFF9 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 A6DFF9 broadcasting right now?
Yes. Mode-S A6DFF9 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A6DFF9, octal 51557771, decimal 10,936,313.
What flights does A6DFF9 operate?
Mode-S A6DFF9 has broadcast 20 distinct callsigns, including GJS4385, GJS4603, GJS4586, GJS4442, GJS4446.