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 18h ago
Flights observed
77
Distinct callsigns
20
Country
CN
Last broadcast
18h ago

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 - 5 2026-05-19
CSS127 - 5 2026-05-19
CSS6802 SF Airlines 3 2026-05-27
CSS335 SF Airlines 3 2026-05-28
CSS254 - 3 2026-05-27
CSS253 - 3 2026-05-27
CSS240 - 3 2026-04-29
CSS239 SF Airlines 3 2026-04-29
CSS173 - 3 2026-04-30
CSS168 SF Airlines 3 2026-04-18
CSS155 SF Airlines 3 2026-05-08
CSS6805 SF Airlines 2 2026-05-07
CSS364 SF Airlines 2 2026-05-29
CSS363 SF Airlines 2 2026-05-28
CSS302 SF Airlines 2 2026-05-15
CSS231 SF Airlines 2 2026-05-25
CSS172 - 2 2026-05-22
CSS167 - 2 2026-04-17
CSS161 SF Airlines 2 2026-04-15
CSS160 SF Airlines 2 2026-04-29

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-05-29 CSS6809 - May 29, 17:35 UTCMay 29, 17:45 UTC10m
2026-05-29 CSS364 NRT → SZX May 29, 05:40 UTCMay 29, 05:50 UTC10m
2026-05-29 CSS364 NRT → SZX May 29, 01:25 UTCMay 29, 02:55 UTC1h 30m
2026-05-28 CSS363 SZX → NRT May 28, 22:10 UTCMay 28, 23:20 UTC1h 10m
2026-05-28 CSS363 SZX → NRT May 28, 19:40 UTCMay 28, 19:55 UTC15m
2026-05-28 CSS335 SZX → MAA May 28, 04:40 UTCMay 28, 14:10 UTC9h 30m
2026-05-27 CSS6802 EHU → SZX May 27, 22:00 UTCMay 27, 22:10 UTC10m
2026-05-27 CSS254 - May 27, 07:30 UTCMay 27, 10:15 UTC2h 45m
2026-05-27 CSS253 - May 27, 04:49 UTCMay 27, 05:14 UTC25m
2026-05-27 CSS253 - May 27, 02:54 UTCMay 27, 04:14 UTC1h 20m
2026-05-25 CSS232 - May 25, 06:55 UTCMay 25, 09:45 UTC2h 50m
2026-05-25 CSS231 CTU → BOM May 25, 04:45 UTCMay 25, 04:55 UTC10m
2026-05-25 CSS231 CTU → BOM May 25, 02:00 UTCMay 25, 02:55 UTC55m
2026-05-22 CSS172 - May 22, 09:10 UTCMay 22, 10:10 UTC1h 0m
2026-05-22 CSS172 - May 22, 00:50 UTCMay 22, 04:50 UTC4h 0m
2026-05-21 CSS171 - May 21, 19:40 UTCMay 21, 22:20 UTC2h 40m
2026-05-19 CSS128 - May 19, 23:35 UTCMay 20, 17:40 UTC18h 6m
2026-05-19 CSS128 - May 19, 18:50 UTCMay 20, 17:40 UTC22h 51m
2026-05-19 CSS128 - May 19, 18:35 UTCMay 20, 11:55 UTC17h 21m
2026-05-19 CSS127 - May 19, 07:30 UTCMay 19, 14:50 UTC7h 20m
2026-05-18 CSS127 - May 18, 12:50 UTCMay 19, 10:45 UTC21h 54m
2026-05-18 CSS128 - May 18, 11:05 UTCMay 19, 10:45 UTC23h 39m
2026-05-18 CSS127 - May 18, 07:40 UTCMay 18, 08:05 UTC25m
2026-05-18 CSS127 - May 18, 03:35 UTCMay 18, 05:00 UTC1h 25m
2026-05-15 CSS6801 SZX → EHU May 15, 17:45 UTCMay 15, 17:55 UTC10m
2026-05-15 CSS335 SZX → MAA May 15, 05:55 UTCMay 15, 12:55 UTC7h 0m
2026-05-15 CSS335 SZX → MAA May 15, 03:00 UTCMay 15, 03:15 UTC15m
2026-05-15 CSS302 SIN → SZX May 15, 00:45 UTCMay 15, 01:05 UTC20m
2026-05-14 CSS302 SIN → SZX May 14, 21:30 UTCMay 14, 21:50 UTC20m
2026-05-14 CSS301 SZX → SIN May 14, 15:45 UTCMay 14, 19:20 UTC3h 35m
2026-05-13 CSS6804 EHU → SZX May 13, 20:45 UTCMay 13, 20:55 UTC10m
2026-05-09 CSS156 LHE → EHU May 9, 12:35 UTCMay 9, 15:05 UTC2h 30m
2026-05-08 CSS155 EHU → LHE May 8, 16:55 UTCMay 9, 10:30 UTC17h 35m
2026-05-08 CSS155 EHU → LHE May 8, 12:49 UTCMay 9, 10:30 UTC21h 40m
2026-05-08 CSS155 EHU → LHE May 8, 11:25 UTCMay 9, 10:30 UTC23h 5m
2026-05-07 CSS6805 SZX → EHU May 7, 16:45 UTCMay 7, 16:55 UTC10m
2026-05-06 CSS6802 EHU → SZX May 6, 22:15 UTCMay 6, 22:25 UTC10m
2026-05-04 CSS6835 SZX → HGH May 4, 21:10 UTCMay 4, 21:20 UTC10m
2026-05-04 CSS7223 HGH → SZX May 4, 19:00 UTCMay 4, 19:15 UTC15m
2026-05-01 CSS158 DEL → EHU May 1, 12:45 UTCMay 1, 14:40 UTC1h 55m
2026-04-30 CSS157 EHU → DEL Apr 30, 21:40 UTCMay 1, 10:50 UTC13h 10m
2026-04-30 CSS173 - Apr 30, 18:35 UTCApr 30, 19:00 UTC25m
2026-04-30 CSS173 - Apr 30, 15:35 UTCApr 30, 17:30 UTC1h 55m
2026-04-29 CSS173 - Apr 29, 18:50 UTCApr 30, 17:30 UTC22h 40m
2026-04-29 CSS160 DEL → EHU Apr 29, 18:00 UTCApr 30, 16:45 UTC22h 44m
2026-04-29 CSS239 ZUH → DEL Apr 29, 10:05 UTCApr 29, 15:15 UTC5h 10m
2026-04-29 CSS240 - Apr 29, 03:00 UTCApr 29, 05:05 UTC2h 5m
2026-04-28 CSS163 EHU → DEL Apr 28, 21:30 UTCApr 29, 00:20 UTC2h 50m
2026-04-27 CSS160 DEL → EHU Apr 27, 16:45 UTCApr 27, 19:00 UTC2h 15m
2026-04-26 CSS159 EHU → DEL Apr 26, 18:50 UTCApr 27, 14:30 UTC19h 40m

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 18h ago.
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, CSS6802, CSS335, CSS254.