sensors Mode-S transponder

4B1939

ICAO 24-bit transponder address · allocated to Switzerland

Currently assigned to HB-JOJ · AIRBUS A-319

Hex
4B1939
Octal
22614471
Decimal
4,921,657
Country
CH
Tail
HB-JOJ
Type
A319
Broadcasting now · callsign CSW8GJ · 37,000 ft
Flights observed
149
Distinct callsigns
20
Country
CH
Last broadcast
46m ago

Current position

4B1939 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address 4B1939 falls within the block assigned to Switzerland (CH) by ICAO Annex 10, Volume III. Every aircraft registered in Switzerland 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
CSW8GJ - 30 2026-05-30
CSW8HE - 29 2026-05-29
CSW890 - 9 2026-05-02
CSW638 - 8 2026-05-28
CSW803 Worldwide Air Charter Systems 7 2026-05-29
CSW802 Worldwide Air Charter Systems 7 2026-05-29
CSW891 - 6 2026-05-02
CSW805 Worldwide Air Charter Systems 6 2026-05-26
CSW804 Worldwide Air Charter Systems 6 2026-05-26
CSW639 Worldwide Air Charter Systems 6 2026-05-28
CSW631 - 6 2026-05-24
CSW630 - 5 2026-05-24
CSW1PM - 5 2026-05-05
CSW604 - 4 2026-05-17
CSW1EP - 4 2026-05-05
CSW605 - 3 2026-05-03
CSW447 - 2 2026-05-21
CSW6KP - 1 2026-05-03
CSW615 - 1 2026-05-17
CSW607 Worldwide Air Charter Systems 1 2026-05-23

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-05-30 CSW8GJ - May 30, 14:10 UTCMay 30, 14:15 UTC5m
2026-05-29 CSW803 RHO → ZRH May 29, 17:05 UTCMay 29, 20:00 UTC2h 55m
2026-05-29 CSW802 ZRH → RHO May 29, 13:30 UTCMay 29, 16:05 UTC2h 35m
2026-05-29 CSW8HE - May 29, 09:50 UTCMay 29, 12:25 UTC2h 35m
2026-05-29 CSW8GJ - May 29, 06:00 UTCMay 29, 08:20 UTC2h 20m
2026-05-28 CSW639 OHD → ZRH May 28, 19:25 UTCMay 28, 21:00 UTC1h 35m
2026-05-28 CSW638 - May 28, 16:25 UTCMay 28, 17:55 UTC1h 30m
2026-05-27 CSW8HE - May 27, 18:15 UTCMay 27, 20:50 UTC2h 35m
2026-05-27 CSW8GJ - May 27, 14:40 UTCMay 27, 17:05 UTC2h 25m
2026-05-26 CSW805 KGS → ZRH May 26, 08:54 UTCMay 26, 11:30 UTC2h 35m
2026-05-26 CSW804 ZRH → KGS May 26, 05:10 UTCMay 26, 07:55 UTC2h 45m
2026-05-25 CSW8HE - May 25, 17:55 UTCMay 25, 20:19 UTC2h 25m
2026-05-25 CSW8GJ - May 25, 14:15 UTCMay 25, 16:45 UTC2h 30m
2026-05-25 CSW803 RHO → ZRH May 25, 08:40 UTCMay 25, 11:30 UTC2h 50m
2026-05-25 CSW802 ZRH → RHO May 25, 04:55 UTCMay 25, 07:40 UTC2h 45m
2026-05-24 CSW631 - May 24, 17:35 UTCMay 24, 19:25 UTC1h 50m
2026-05-24 CSW630 - May 24, 14:20 UTCMay 24, 16:00 UTC1h 40m
2026-05-24 CSW805 KGS → ZRH May 24, 08:55 UTCMay 24, 11:35 UTC2h 40m
2026-05-24 CSW804 ZRH → KGS May 24, 05:05 UTCMay 24, 07:40 UTC2h 35m
2026-05-23 CSW8HE - May 23, 17:45 UTCMay 23, 20:15 UTC2h 31m
2026-05-23 CSW8GJ - May 23, 14:10 UTCMay 23, 16:35 UTC2h 25m
2026-05-23 CSW607 PRN → ZRH May 23, 09:00 UTCMay 23, 10:40 UTC1h 40m
2026-05-23 CSW606 ZRH → PRN May 23, 04:45 UTCMay 23, 06:20 UTC1h 35m
2026-05-22 CSW803 RHO → ZRH May 22, 17:35 UTCMay 22, 20:15 UTC2h 40m
2026-05-22 CSW802 ZRH → RHO May 22, 13:40 UTCMay 22, 16:15 UTC2h 35m
2026-05-22 CSW8HE - May 22, 09:50 UTCMay 22, 12:40 UTC2h 50m
2026-05-22 CSW8GJ - May 22, 06:00 UTCMay 22, 08:20 UTC2h 20m
2026-05-21 CSW639 OHD → ZRH May 21, 19:05 UTCMay 21, 20:55 UTC1h 50m
2026-05-21 CSW638 - May 21, 16:20 UTCMay 21, 17:45 UTC1h 25m
2026-05-21 CSW447 ZRH → ZRH May 21, 04:45 UTCMay 21, 14:45 UTC10h 0m
2026-05-20 CSW8HE - May 20, 18:00 UTCMay 20, 20:35 UTC2h 35m
2026-05-20 CSW8GJ - May 20, 14:30 UTCMay 20, 16:45 UTC2h 15m
2026-05-19 CSW805 KGS → ZRH May 19, 08:50 UTCMay 19, 11:30 UTC2h 40m
2026-05-19 CSW804 ZRH → KGS May 19, 04:50 UTCMay 19, 07:20 UTC2h 30m
2026-05-18 CSW8HE - May 18, 17:30 UTCMay 18, 20:10 UTC2h 39m
2026-05-18 CSW8GJ - May 18, 13:45 UTCMay 18, 16:05 UTC2h 20m
2026-05-18 CSW803 RHO → ZRH May 18, 08:35 UTCMay 18, 11:50 UTC3h 15m
2026-05-18 CSW802 ZRH → RHO May 18, 04:51 UTCMay 18, 07:35 UTC2h 45m
2026-05-17 CSW615 - May 17, 17:01 UTCMay 17, 18:45 UTC1h 45m
2026-05-17 CSW604 - May 17, 14:15 UTCMay 17, 15:40 UTC1h 25m
2026-05-17 CSW805 KGS → ZRH May 17, 08:30 UTCMay 17, 11:20 UTC2h 50m
2026-05-17 CSW804 ZRH → KGS May 17, 05:15 UTCMay 17, 07:35 UTC2h 20m
2026-05-16 CSW8HE - May 16, 18:15 UTCMay 16, 21:00 UTC2h 45m
2026-05-16 CSW8GJ - May 16, 14:46 UTCMay 16, 16:55 UTC2h 10m
2026-05-15 CSW803 RHO → ZRH May 15, 17:25 UTCMay 15, 20:45 UTC3h 20m
2026-05-15 CSW802 ZRH → RHO May 15, 13:45 UTCMay 15, 16:15 UTC2h 29m
2026-05-15 CSW8HE - May 15, 09:40 UTCMay 15, 12:30 UTC2h 50m
2026-05-15 CSW8GJ - May 15, 06:00 UTCMay 15, 08:05 UTC2h 5m
2026-05-14 CSW639 OHD → ZRH May 14, 19:20 UTCMay 14, 21:00 UTC1h 40m
2026-05-14 CSW638 - May 14, 16:30 UTCMay 14, 17:55 UTC1h 25m

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 HB-JOJ page for operator, model, and routing details .

Mode-S 4B1939 frequently asked

What is Mode-S code 4B1939?
4B1939 is an ICAO 24-bit transponder address. Allocated to Switzerland. Assigned to HB-JOJ.
Where is Mode-S 4B1939 registered?
Mode-S code 4B1939 is allocated to Switzerland (CH). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 4B1939 broadcasting right now?
Yes. Mode-S 4B1939 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 4B1939, octal 22614471, decimal 4,921,657.
What flights does 4B1939 operate?
Mode-S 4B1939 has broadcast 20 distinct callsigns, including CSW8GJ, CSW8HE, CSW890, CSW638, CSW803.