Apparatus

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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
No current signal · last broadcast Jul 26, 20:55 UTC
Flights observed
402
Distinct callsigns
20
Country
CH
Last broadcast
Jul 26, 20:55 UTC

Last known position

Most recent position reported by Mode-S 4B1691.

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

Callsign Airline Flights Last seen
SWR1LK - 8 2026-06-19
SWR9TP Swiss International Air Lines 7 2026-07-22
SWR87C - 7 2026-06-22
SWR5AM - 7 2026-07-20
SWR4TD Swiss International Air Lines 7 2026-06-22
SWR4ET - 7 2026-06-19
SWR493Z - 7 2026-07-04
SWR3ZK - 7 2026-07-22
SWR27G - 7 2026-07-04
SWR26W - 7 2026-07-22
SWR9PX Swiss International Air Lines 6 2026-07-23
SWR7VE Swiss International Air Lines 6 2026-07-22
SWR589X - 6 2026-07-23
SWR1ZB - 6 2026-07-20
SWR5CB - 5 2026-07-19
SWR465K - 5 2026-07-17
SWR2XH Swiss International Air Lines 5 2026-04-26
SWR1PL - 5 2026-07-19
SWR9LC Swiss International Air Lines 4 2026-07-26
SWR98P Swiss International Air Lines 4 2026-04-26

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 SWR9LC ZRH → BER Jul 26, 19:50 UTCJul 26, 20:55 UTC1h 5m
2026-07-26 SWR2GX LIS → ZRH Jul 26, 15:25 UTCJul 26, 17:55 UTC2h 30m
2026-07-26 SWR2BK ZRH → LIS Jul 26, 11:45 UTCJul 26, 14:00 UTC2h 15m
2026-07-26 SWR5MW TIA → ZRH Jul 26, 08:35 UTCJul 26, 10:15 UTC1h 40m
2026-07-26 SWR89T ZRH → TIA Jul 26, 05:30 UTCJul 26, 06:40 UTC1h 11m
2026-07-25 SWR5TV OPO → ZRH Jul 25, 18:45 UTCJul 25, 21:00 UTC2h 15m
2026-07-25 SWR82L ZRH → OPO Jul 25, 15:20 UTCJul 25, 17:35 UTC2h 15m
2026-07-25 SWR5GT FCO → ZRH Jul 25, 11:25 UTCJul 25, 12:50 UTC1h 25m
2026-07-25 SWR2EP BCN → ZRH Jul 25, 08:50 UTCJul 25, 10:20 UTC1h 30m
2026-07-25 SWR1PM ARN → ZRH Jul 25, 04:25 UTCJul 25, 06:30 UTC2h 5m
2026-07-24 SWR1KV ZRH → ARN Jul 24, 19:50 UTCJul 24, 22:05 UTC2h 15m
2026-07-24 SWR2GX LIS → ZRH Jul 24, 16:20 UTCJul 24, 18:25 UTC2h 5m
2026-07-24 SWR2BK ZRH → LIS Jul 24, 12:10 UTCJul 24, 14:55 UTC2h 45m
2026-07-24 SWR9ZA OPO → ZRH Jul 24, 08:25 UTCJul 24, 10:25 UTC2h 0m
2026-07-24 SWR2LM ZRH → FRA Jul 24, 04:35 UTCJul 24, 06:55 UTC2h 20m
2026-07-23 SWR589X ARN → ZRH Jul 23, 14:10 UTCJul 23, 15:50 UTC1h 40m
2026-07-23 SWR9PX ZRH → ALC Jul 23, 10:50 UTCJul 23, 13:00 UTC2h 10m
2026-07-22 SWR9TP GVA → ZRH Jul 22, 19:10 UTCJul 22, 19:45 UTC35m
2026-07-22 SWR3ZK ZRH → GVA Jul 22, 17:30 UTCJul 22, 18:05 UTC35m
2026-07-22 SWR26W - Jul 22, 15:00 UTCJul 22, 16:20 UTC1h 20m
2026-07-22 SWR7VE ZRH → CPH Jul 22, 12:20 UTCJul 22, 13:50 UTC1h 30m
2026-07-22 SWR4KG - Jul 22, 05:10 UTCJul 22, 05:25 UTC15m
2026-07-21 SWR42V CDG → ZRH Jul 21, 18:10 UTCJul 21, 18:55 UTC45m
2026-07-21 SWR1DE ZRH → CDG Jul 21, 15:50 UTCJul 21, 16:45 UTC55m
2026-07-21 SWR20D OPO → ZRH Jul 21, 12:00 UTCJul 21, 14:10 UTC2h 10m
2026-07-21 SWR8BC ZRH → OPO Jul 21, 08:05 UTCJul 21, 10:25 UTC2h 20m
2026-07-21 SWR5XL BER → ZRH Jul 21, 05:25 UTCJul 21, 06:25 UTC1h 0m
2026-07-20 SWR9LC ZRH → BER Jul 20, 19:35 UTCJul 20, 20:45 UTC1h 10m
2026-07-20 SWR1ZB ATH → ZRH Jul 20, 14:05 UTCJul 20, 16:30 UTC2h 25m
2026-07-20 SWR5AM ZRH → ATH Jul 20, 10:35 UTCJul 20, 12:45 UTC2h 10m
2026-07-19 SWR5YG - Jul 19, 18:45 UTCJul 19, 19:30 UTC45m
2026-07-19 SWR9CW ZRH → VCE Jul 19, 17:05 UTCJul 19, 17:45 UTC40m
2026-07-19 SWR5CB BER → ZRH Jul 19, 14:30 UTCJul 19, 15:35 UTC1h 5m
2026-07-19 SWR1PL ZRH → BER Jul 19, 12:05 UTCJul 19, 13:05 UTC1h 0m
2026-07-19 SWR2WX - Jul 19, 08:15 UTCJul 19, 09:35 UTC1h 20m
2026-07-19 SWR193T ZRH → CPH Jul 19, 05:45 UTCJul 19, 07:05 UTC1h 20m
2026-07-18 SWR72L MUC → ZRH Jul 18, 19:15 UTCJul 18, 19:45 UTC30m
2026-07-18 SWR7PE - Jul 18, 17:25 UTCJul 18, 18:05 UTC40m
2026-07-18 SWR26W - Jul 18, 14:40 UTCJul 18, 16:05 UTC1h 25m
2026-07-18 SWR7VE ZRH → CPH Jul 18, 11:10 UTCJul 18, 12:35 UTC1h 25m
2026-07-18 SWR90Y BDS → ZRH Jul 18, 07:55 UTCJul 18, 09:35 UTC1h 40m
2026-07-18 SWR4KG ZRH → BDS Jul 18, 05:10 UTCJul 18, 06:40 UTC1h 30m
2026-07-17 SWR57Z - Jul 17, 18:55 UTCJul 17, 20:35 UTC1h 40m
2026-07-17 SWR465K - Jul 17, 14:39 UTCJul 17, 16:44 UTC2h 5m
2026-07-17 SWR5EZ ALC → ZRH Jul 17, 11:30 UTCJul 17, 13:15 UTC1h 45m
2026-07-17 SWR1V - Jul 17, 08:00 UTCJul 17, 10:00 UTC2h 0m
2026-07-17 SWR8AD CPH → ZRH Jul 17, 04:54 UTCJul 17, 06:20 UTC1h 25m
2026-07-16 SWR44X ZRH → CPH Jul 16, 21:10 UTCJul 16, 22:30 UTC1h 20m
2026-07-16 SWR2EZ GVA → ZRH Jul 16, 18:40 UTCJul 16, 19:14 UTC35m
2026-07-16 SWR3CX ZRH → GVA Jul 16, 15:49 UTCJul 16, 16:25 UTC35m

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?
No active broadcast right now. Last signal was Jul 26, 20:55 UTC.
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, SWR9TP, SWR87C, SWR5AM, SWR4TD.