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
No current signal · last broadcast 25m ago
Flights observed
543
Distinct callsigns
20
Country
US
Last broadcast
25m ago

Last known position

Most recent position reported by Mode-S A6DFF9.

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
GJS4603 - 9 2026-06-27
GJS4385 GoJet Airlines 9 2026-06-06
GJS4605 - 7 2026-07-12
GJS4586 GoJet Airlines 7 2026-06-04
GJS4388 - 7 2026-06-27
GJS4187 - 7 2026-07-09
GJS4601 - 6 2026-06-30
GJS4446 GoJet Airlines 6 2026-05-23
GJS4410 - 6 2026-06-18
GJS4389 - 6 2026-07-02
GJS4191 - 6 2026-07-06
GJS4600 GoJet Airlines 5 2026-06-10
GJS4592 - 5 2026-07-11
GJS4580 GoJet Airlines 5 2026-06-02
GJS4546 - 5 2026-06-27
GJS4535 GoJet Airlines 5 2026-05-26
GJS4510 - 5 2026-06-20
GJS4501 - 5 2026-06-22
GJS4492 GoJet Airlines 5 2026-06-16
GJS4447 - 5 2026-06-22

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-14 GJS4186 - Jul 14, 12:50 UTCJul 14, 14:15 UTC1h 25m
2026-07-14 GJS4415 - Jul 14, 10:05 UTCJul 14, 11:10 UTC1h 5m
2026-07-13 GJS4484 - Jul 13, 23:30 UTCJul 14, 00:15 UTC45m
2026-07-13 GJS4484 ORD → DAY Jul 13, 23:24 UTCJul 14, 00:16 UTC52m
2026-07-13 GJS4564 - Jul 13, 20:05 UTCJul 13, 21:25 UTC1h 20m
2026-07-13 GJS4431 - Jul 13, 17:40 UTCJul 13, 18:50 UTC1h 10m
2026-07-13 GJS4572 ROA → ORD Jul 13, 14:55 UTCJul 13, 16:15 UTC1h 20m
2026-07-13 GJS4186 - Jul 13, 11:55 UTCJul 13, 13:15 UTC1h 20m
2026-07-12 GJS4605 - Jul 12, 16:05 UTCJul 12, 16:55 UTC50m
2026-07-12 GJS4392 - Jul 12, 13:55 UTCJul 12, 14:35 UTC40m
2026-07-12 GJS4166 ABE → ORD Jul 12, 10:33 UTCJul 12, 11:48 UTC1h 15m
2026-07-12 GJS4166 ABE → ORD Jul 12, 10:20 UTCJul 12, 12:01 UTC1h 40m
2026-07-11 GJS4463 - Jul 11, 23:15 UTCJul 12, 00:40 UTC1h 25m
2026-07-11 GJS4463 ORD → ABE Jul 11, 23:28 UTCJul 12, 00:59 UTC1h 31m
2026-07-11 GJS4452 STL → ORD Jul 11, 21:05 UTCJul 11, 21:50 UTC45m
2026-07-11 GJS4581 - Jul 11, 18:20 UTCJul 11, 19:15 UTC55m
2026-07-11 GJS4583 GRR → ORD Jul 11, 15:45 UTCJul 11, 16:30 UTC45m
2026-07-11 GJS4583 GRR → ORD Jul 11, 15:52 UTCJul 11, 16:24 UTC32m
2026-07-11 GJS4592 - Jul 11, 11:20 UTCJul 11, 11:45 UTC25m
2026-07-11 GJS4592 ORD → GRR Jul 11, 11:19 UTCJul 11, 11:57 UTC38m
2026-07-10 GJS4438 - Jul 10, 14:55 UTCJul 10, 16:40 UTC1h 45m
2026-07-10 GJS4438 AVP → ORD Jul 10, 14:21 UTCJul 10, 16:28 UTC2h 7m
2026-07-09 GJS4187 - Jul 9, 23:40 UTCJul 10, 01:00 UTC1h 20m
2026-07-09 GJS4187 ORD → AVP Jul 9, 23:39 UTCJul 10, 01:05 UTC1h 26m
2026-07-09 GJS4391 - Jul 9, 21:40 UTCJul 9, 22:15 UTC35m
2026-07-09 GJS4391 ATW → ORD Jul 9, 21:35 UTCJul 9, 22:04 UTC29m
2026-07-09 GJS4479 - Jul 9, 20:20 UTCJul 9, 20:55 UTC35m
2026-07-09 GJS4547 - Jul 9, 17:20 UTCJul 9, 19:00 UTC1h 40m
2026-07-07 GJS4386 - Jul 7, 02:30 UTCJul 7, 03:20 UTC50m
2026-07-07 GJS4386 EWR → RIC Jul 7, 02:06 UTCJul 7, 03:23 UTC1h 17m
2026-07-07 GJS4401 DCA → EWR Jul 7, 00:10 UTCJul 7, 00:45 UTC35m
2026-07-07 GJS4401 DCA → EWR Jul 7, 00:09 UTCJul 7, 00:48 UTC39m
2026-07-06 GJS4433 EWR → DCA Jul 6, 19:15 UTCJul 6, 20:00 UTC45m
2026-07-06 GJS4433 EWR → DCA Jul 6, 18:43 UTCJul 6, 19:55 UTC1h 12m
2026-07-06 GJS4182 - Jul 6, 16:40 UTCJul 6, 17:35 UTC55m
2026-07-06 GJS4182 ACK → EWR Jul 6, 16:36 UTCJul 6, 17:38 UTC1h 2m
2026-07-06 GJS4497 - Jul 6, 14:10 UTCJul 6, 14:50 UTC40m
2026-07-06 GJS4191 - Jul 6, 10:25 UTCJul 6, 11:20 UTC55m
2026-07-06 GJS3376 - Jul 6, 01:00 UTCJul 6, 02:35 UTC1h 35m
2026-07-05 GJS4509 - Jul 5, 21:45 UTCJul 5, 23:20 UTC1h 35m
2026-07-05 GJS4442 DCA → EWR Jul 5, 17:50 UTCJul 5, 18:40 UTC50m
2026-07-05 GJS4442 DCA → EWR Jul 5, 17:47 UTCJul 5, 18:34 UTC47m
2026-07-05 GJS4172 - Jul 5, 16:20 UTCJul 5, 17:05 UTC45m
2026-07-05 GJS4430 DCA → EWR Jul 5, 12:50 UTCJul 5, 13:35 UTC45m
2026-07-05 GJS4437 EWR → DCA Jul 5, 10:55 UTCJul 5, 11:40 UTC45m
2026-07-05 GJS4437 EWR → DCA Jul 5, 10:51 UTCJul 5, 11:36 UTC45m
2026-07-04 GJS4457 - Jul 4, 19:45 UTCJul 4, 20:50 UTC1h 5m
2026-07-04 GJS4396 - Jul 4, 17:30 UTCJul 4, 18:20 UTC50m
2026-07-04 GJS4536 PWM → IAD Jul 4, 10:20 UTCJul 4, 11:25 UTC1h 5m
2026-07-03 GJS4552 EWR → BUF Jul 3, 21:10 UTCJul 3, 22:10 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 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?
No active broadcast right now. Last signal was 25m ago.
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 GJS4603, GJS4385, GJS4605, GJS4586, GJS4388.