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sensors Mode-S transponder

781B4B

ICAO 24-bit transponder address · allocated to China

Currently assigned to B-220R · BOEING 767-300

Hex
781B4B
Octal
36015513
Decimal
7,871,307
Country
CN
Tail
B-220R
Type
B763
No current signal · last broadcast Jul 23, 17:55 UTC
Flights observed
155
Distinct callsigns
20
Country
CN
Last broadcast
Jul 23, 17:55 UTC

Last known position

Most recent position reported by Mode-S 781B4B.

Country allocation

The ICAO 24-bit address 781B4B falls within the block assigned to China (CN) by ICAO Annex 10, Volume III. Every aircraft registered in China 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
CSS128 - 13 2026-07-19
CSS127 - 12 2026-07-18
CSS122 - 8 2026-07-14
CSS161 - 7 2026-06-30
CSS148 - 7 2026-07-01
CSS121 - 7 2026-07-14
CSS239 SF Airlines 6 2026-06-18
CSS159 - 6 2026-06-28
CSS240 - 5 2026-06-13
CSS6802 SF Airlines 4 2026-06-05
CSS6801 SF Airlines 4 2026-07-23
CSS254 - 4 2026-06-24
CSS253 - 4 2026-06-24
CSS173 - 4 2026-06-28
CSS169 - 4 2026-07-05
CSS155 - 4 2026-07-10
CSS335 SF Airlines 3 2026-05-28
CSS168 SF Airlines 3 2026-04-18
CSS160 - 3 2026-06-29
CSS7635 - 2 2026-07-09

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-23 CSS6801 SZX → EHU Jul 23, 17:45 UTCJul 23, 17:55 UTC10m
2026-07-21 CSS358 TPE → SZX Jul 21, 03:00 UTCJul 21, 04:15 UTC1h 15m
2026-07-20 CSS357 - Jul 20, 23:40 UTCJul 21, 01:05 UTC1h 24m
2026-07-20 CSS6804 - Jul 20, 21:20 UTCJul 20, 21:30 UTC10m
2026-07-19 CSS128 - Jul 19, 14:35 UTCJul 19, 20:25 UTC5h 50m
2026-07-18 CSS206 BUD → BUD Jul 18, 17:00 UTCJul 19, 12:20 UTC19h 20m
2026-07-18 CSS127 - Jul 18, 11:15 UTCJul 18, 14:55 UTC3h 40m
2026-07-17 CSS6801 - Jul 17, 17:25 UTCJul 17, 17:35 UTC10m
2026-07-16 CSS6846 - Jul 16, 23:20 UTCJul 16, 23:59 UTC40m
2026-07-16 CSS6845 - Jul 16, 18:55 UTCJul 16, 19:05 UTC10m
2026-07-16 CSS358 - Jul 16, 03:15 UTCJul 16, 04:25 UTC1h 10m
2026-07-15 CSS357 - Jul 15, 23:45 UTCJul 16, 01:10 UTC1h 25m
2026-07-15 CSS6806 - Jul 15, 20:50 UTCJul 15, 21:05 UTC15m
2026-07-14 CSS122 - Jul 14, 18:50 UTCJul 15, 02:05 UTC7h 14m
2026-07-14 CSS121 - Jul 14, 08:30 UTCJul 14, 16:20 UTC7h 50m
2026-07-12 CSS7103 - Jul 12, 16:35 UTCJul 12, 16:50 UTC15m
2026-07-11 CSS7104 - Jul 11, 21:50 UTCJul 11, 22:05 UTC15m
2026-07-11 CSS156 - Jul 11, 11:30 UTCJul 11, 14:50 UTC3h 20m
2026-07-10 CSS155 - Jul 10, 16:55 UTCJul 11, 09:40 UTC16h 45m
2026-07-09 CSS7635 - Jul 9, 22:10 UTCJul 10, 17:15 UTC19h 5m
2026-07-09 CSS264 - Jul 9, 10:10 UTCJul 9, 22:15 UTC12h 5m
2026-07-09 CSS263 - Jul 9, 07:35 UTCJul 9, 08:10 UTC35m
2026-07-05 CSS169 - Jul 5, 10:45 UTCJul 5, 18:25 UTC7h 40m
2026-07-03 CSS128 - Jul 3, 18:55 UTCJul 4, 00:50 UTC5h 55m
2026-07-03 CSS127 - Jul 3, 07:15 UTCJul 3, 15:35 UTC8h 20m
2026-07-02 CSS127 - Jul 2, 18:50 UTCJul 3, 15:35 UTC20h 45m
2026-07-02 CSS170 - Jul 2, 17:25 UTCJul 3, 15:35 UTC22h 10m
2026-07-02 CSS170 - Jul 2, 12:50 UTCJul 3, 07:35 UTC18h 45m
2026-07-02 CSS169 - Jul 2, 11:00 UTCJul 3, 07:35 UTC20h 35m
2026-07-01 CSS169 - Jul 1, 16:50 UTCJul 2, 13:10 UTC20h 20m
2026-07-01 CSS169 - Jul 1, 16:20 UTCJul 2, 13:10 UTC20h 50m
2026-07-01 CSS148 - Jul 1, 00:10 UTCJul 1, 18:25 UTC18h 15m
2026-06-30 CSS161 - Jun 30, 19:35 UTCJun 30, 22:25 UTC2h 50m
2026-06-29 CSS160 - Jun 29, 14:04 UTCJun 29, 16:50 UTC2h 45m
2026-06-28 CSS159 - Jun 28, 21:10 UTCJun 29, 12:14 UTC15h 5m
2026-06-28 CSS173 - Jun 28, 00:39 UTCJun 28, 18:40 UTC18h 0m
2026-06-27 CSS161 - Jun 27, 09:15 UTCJun 27, 22:20 UTC13h 5m
2026-06-26 CSS122 - Jun 26, 14:50 UTCJun 27, 09:24 UTC18h 35m
2026-06-26 CSS121 - Jun 26, 05:19 UTCJun 26, 13:15 UTC7h 55m
2026-06-24 CSS254 - Jun 24, 07:05 UTCJun 24, 09:45 UTC2h 40m
2026-06-24 CSS253 - Jun 24, 02:54 UTCJun 24, 04:30 UTC1h 35m
2026-06-20 CSS7250 - Jun 20, 23:10 UTCJun 20, 23:25 UTC15m
2026-06-19 CSS122 - Jun 19, 15:49 UTCJun 19, 22:45 UTC6h 55m
2026-06-19 CSS121 - Jun 19, 11:59 UTCJun 19, 13:09 UTC1h 10m
2026-06-18 CSS148 - Jun 18, 14:50 UTCJun 19, 13:09 UTC22h 19m
2026-06-18 CSS148 - Jun 18, 14:10 UTCJun 19, 12:44 UTC22h 34m
2026-06-18 CSS239 ZUH → DEL Jun 18, 00:30 UTCJun 18, 12:20 UTC11h 50m
2026-06-17 CSS161 - Jun 17, 19:50 UTCJun 17, 22:15 UTC2h 25m
2026-06-16 CSS161 - Jun 16, 23:35 UTCJun 17, 22:15 UTC22h 40m
2026-06-16 CSS128 - Jun 16, 18:09 UTCJun 17, 00:20 UTC6h 11m

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 B-220R page for operator, model, and routing details .

Mode-S 781B4B frequently asked

What is Mode-S code 781B4B?
781B4B is an ICAO 24-bit transponder address. Allocated to China. Assigned to B-220R.
Where is Mode-S 781B4B registered?
Mode-S code 781B4B is allocated to China (CN). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 781B4B broadcasting right now?
No active broadcast right now. Last signal was Jul 23, 17:55 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 781B4B, octal 36015513, decimal 7,871,307.
What flights does 781B4B operate?
Mode-S 781B4B has broadcast 20 distinct callsigns, including CSS128, CSS127, CSS122, CSS161, CSS148.