sensors Mode-S transponder

4B1691

ICAO 24-bit transponder address · allocated to Switzerland

Currently assigned to HB-IOF · AIRBUS A-321

Hex
4B1691
Octal
22613221
Decimal
4,920,977
Country
CH
Tail
HB-IOF
Type
A321
Broadcasting now · callsign SWR3BP · 35,000 ft
Flights observed
189
Distinct callsigns
20
Country
CH
Last broadcast
14h ago

Current position

4B1691 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address 4B1691 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

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-05-29 EDW45L PRN → ZRH May 29, 19:35 UTCMay 29, 21:05 UTC1h 30m
2026-05-29 EDW49Q ZRH → PRN May 29, 16:25 UTCMay 29, 17:55 UTC1h 30m
2026-05-29 SWR4LT BUD → ZRH May 29, 13:40 UTCMay 29, 14:50 UTC1h 10m
2026-05-29 SWR51K ZRH → LYS May 29, 11:20 UTCMay 29, 12:35 UTC1h 15m
2026-05-29 SWR9YD BER → ZRH May 29, 08:20 UTCMay 29, 09:50 UTC1h 30m
2026-05-29 SWR268A ZRH → BUD May 29, 05:45 UTCMay 29, 06:55 UTC1h 10m
2026-05-28 SWR52F DUS → ZRH May 28, 18:35 UTCMay 28, 19:25 UTC50m
2026-05-28 SWR4WP ZRH → DUS May 28, 16:20 UTCMay 28, 17:10 UTC50m
2026-05-28 SWR20D OPO → ZRH May 28, 11:40 UTCMay 28, 14:05 UTC2h 25m
2026-05-28 SWR8BC ZRH → OPO May 28, 08:05 UTCMay 28, 10:20 UTC2h 15m
2026-05-28 SWR3AP VLC → ZRH May 28, 04:10 UTCMay 28, 05:55 UTC1h 45m
2026-05-27 SWR40L ZRH → VLC May 27, 20:15 UTCMay 27, 22:00 UTC1h 45m
2026-05-27 SWR7ZX WRO → ZRH May 27, 17:45 UTCMay 27, 18:55 UTC1h 10m
2026-05-27 SWR5TQ ZRH → WRO May 27, 15:25 UTCMay 27, 16:35 UTC1h 10m
2026-05-27 SWR3HY GVA → ZRH May 27, 09:50 UTCMay 27, 10:20 UTC30m
2026-05-27 SWR291X ZRH → GVA May 27, 07:25 UTCMay 27, 07:55 UTC30m
2026-05-26 SWR465Y ALC → ZRH May 26, 18:45 UTCMay 26, 20:34 UTC1h 50m
2026-05-26 SWR374P ZRH → ALC May 26, 15:24 UTCMay 26, 17:20 UTC1h 55m
2026-05-26 SWR935L ATH → ZRH May 26, 11:30 UTCMay 26, 13:54 UTC2h 25m
2026-05-26 SWR9LA ZRH → ATH May 26, 07:45 UTCMay 26, 10:14 UTC2h 30m
2026-05-25 SWR105W HAM → ZRH May 25, 18:25 UTCMay 25, 19:30 UTC1h 5m
2026-05-25 SWR9D ZRH → HAM May 25, 16:05 UTCMay 25, 17:10 UTC1h 5m
2026-05-25 SWR80K PMI → ZRH May 25, 13:15 UTCMay 25, 14:45 UTC1h 30m
2026-05-25 SWR9EB ZRH → PMI May 25, 10:30 UTCMay 25, 11:55 UTC1h 25m
2026-05-25 SWR7AK NCE → ZRH May 25, 08:15 UTCMay 25, 09:10 UTC55m
2026-05-25 SWR42B ZRH → NCE May 25, 06:10 UTCMay 25, 07:00 UTC50m
2026-05-24 SWR259T FCO → ZRH May 24, 18:55 UTCMay 24, 20:15 UTC1h 20m
2026-05-24 SWR9BL ZRH → FCO May 24, 16:15 UTCMay 24, 17:20 UTC1h 5m
2026-05-24 SWR4TD BCN → ZRH May 24, 13:20 UTCMay 24, 14:55 UTC1h 35m
2026-05-24 SWR87C ZRH → BCN May 24, 10:45 UTCMay 24, 12:00 UTC1h 15m
2026-05-24 SWR44E BER → ZRH May 24, 08:00 UTCMay 24, 09:10 UTC1h 10m
2026-05-24 SWR97Y ZRH → BER May 24, 05:35 UTCMay 24, 06:45 UTC1h 10m
2026-05-23 SWR731C HAM → ZRH May 23, 09:15 UTCMay 23, 10:15 UTC1h 0m
2026-05-23 SWR92W ZRH → HAM May 23, 07:00 UTCMay 23, 08:10 UTC1h 10m
2026-05-23 SWR4VE GVA → FRA May 23, 04:10 UTCMay 23, 05:45 UTC1h 35m
2026-05-22 SWR4KB ZRH → BCN May 22, 20:35 UTCMay 22, 22:05 UTC1h 30m
2026-05-22 SWR5YG VCE → ZRH May 22, 18:25 UTCMay 22, 19:05 UTC40m
2026-05-22 SWR9CW ZRH → VCE May 22, 16:25 UTCMay 22, 17:05 UTC40m
2026-05-22 SWR493Z HAM → ZRH May 22, 13:15 UTCMay 22, 14:20 UTC1h 5m
2026-05-22 SWR27G ZRH → HAM May 22, 11:05 UTCMay 22, 12:10 UTC1h 5m
2026-05-22 SWR5XL BER → ZRH May 22, 05:30 UTCMay 22, 06:30 UTC1h 0m
2026-05-21 SWR9LC ZRH → BER May 21, 20:45 UTCMay 21, 21:45 UTC1h 0m
2026-05-21 SWR9YH LUX → ZRH May 21, 18:05 UTCMay 21, 18:45 UTC40m
2026-05-21 SWR3AG ZRH → LUX May 21, 16:15 UTCMay 21, 16:50 UTC35m
2026-05-21 SWR1YT BDS → ZRH May 21, 13:20 UTCMay 21, 15:00 UTC1h 40m
2026-05-21 SWR3BP ZRH → BDS May 21, 10:25 UTCMay 21, 12:00 UTC1h 35m
2026-05-20 SWR4TD BCN → ZRH May 20, 13:30 UTCMay 20, 14:55 UTC1h 25m
2026-05-20 SWR87C ZRH → BCN May 20, 10:45 UTCMay 20, 12:05 UTC1h 20m
2026-05-18 SWR259T FCO → ZRH May 18, 18:35 UTCMay 18, 19:55 UTC1h 20m
2026-05-18 SWR9BL ZRH → FCO May 18, 16:20 UTCMay 18, 17:20 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 HB-IOF page for operator, model, and routing details .

Mode-S 4B1691 frequently asked

What is Mode-S code 4B1691?
4B1691 is an ICAO 24-bit transponder address. Allocated to Switzerland. Assigned to HB-IOF.
Where is Mode-S 4B1691 registered?
Mode-S code 4B1691 is allocated to Switzerland (CH). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 4B1691 broadcasting right now?
Yes. Mode-S 4B1691 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 4B1691, octal 22613221, decimal 4,920,977.
What flights does 4B1691 operate?
Mode-S 4B1691 has broadcast 20 distinct callsigns, including SWR1LK, SWR87C, SWR4TD, SWR4ET, SWR493Z.