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sensors Mode-S transponder

781C40

ICAO 24-bit transponder address · allocated to China

Currently assigned to B-221D · BOEING 767-300

Hex
781C40
Octal
36016100
Decimal
7,871,552
Country
CN
Tail
B-221D
Type
B763
Broadcasting now · callsign CSS238 · 37,000 ft
Flights observed
128
Distinct callsigns
20
Country
CN
Last broadcast
17m ago

Current position

781C40 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address 781C40 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
CSS241 - 15 2026-07-15
CSS363 - 9 2026-07-10
CSS364 - 8 2026-07-11
CSS242 - 8 2026-07-15
CSS231 - 7 2026-07-07
CSS253 - 6 2026-07-17
CSS159 - 6 2026-06-21
CSS254 - 5 2026-07-17
CSS6801 - 4 2026-07-13
CSS239 SF Airlines 4 2026-06-20
CSS237 SF Airlines 4 2026-05-30
CSS163 - 4 2026-06-16
CSS7635 SF Airlines 3 2026-06-02
CSS7223 - 3 2026-06-27
CSS6845 - 3 2026-07-09
CSS232 - 3 2026-07-07
CSS161 - 3 2026-06-20
CSS7103 - 2 2026-06-25
CSS6846 - 2 2026-07-09
CSS357 SF Airlines 2 2026-05-25

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-17 CSS254 - Jul 17, 08:04 UTCJul 18, 08:00 UTC23h 56m
2026-07-17 CSS254 - Jul 17, 07:05 UTCJul 18, 02:50 UTC19h 46m
2026-07-17 CSS253 - Jul 17, 02:10 UTCJul 17, 04:04 UTC1h 55m
2026-07-15 CSS242 - Jul 15, 07:30 UTCJul 15, 10:20 UTC2h 50m
2026-07-15 CSS241 - Jul 15, 02:55 UTCJul 15, 05:35 UTC2h 40m
2026-07-13 CSS6801 - Jul 13, 17:20 UTCJul 13, 17:35 UTC15m
2026-07-11 CSS364 - Jul 11, 05:40 UTCJul 11, 06:05 UTC25m
2026-07-11 CSS364 - Jul 11, 02:00 UTCJul 11, 03:35 UTC1h 35m
2026-07-10 CSS363 - Jul 10, 21:55 UTCJul 10, 23:40 UTC1h 45m
2026-07-10 CSS363 - Jul 10, 19:40 UTCJul 10, 19:55 UTC15m
2026-07-09 CSS6846 - Jul 9, 20:00 UTCJul 10, 00:35 UTC4h 35m
2026-07-09 CSS6845 - Jul 9, 19:20 UTCJul 9, 19:30 UTC10m
2026-07-09 CSS6846 - Jul 9, 00:45 UTCJul 9, 00:55 UTC10m
2026-07-08 CSS6845 - Jul 8, 19:25 UTCJul 8, 19:40 UTC15m
2026-07-07 CSS6845 - Jul 7, 19:20 UTCJul 7, 19:30 UTC10m
2026-07-07 CSS7413 - Jul 7, 15:25 UTCJul 7, 15:35 UTC10m
2026-07-07 CSS232 - Jul 7, 07:05 UTCJul 7, 10:35 UTC3h 30m
2026-07-07 CSS231 - Jul 7, 04:15 UTCJul 7, 04:40 UTC25m
2026-07-07 CSS231 - Jul 7, 01:20 UTCJul 7, 03:00 UTC1h 40m
2026-07-05 CSS242 - Jul 5, 11:40 UTCJul 5, 14:25 UTC2h 45m
2026-07-05 CSS241 - Jul 5, 09:10 UTCJul 5, 09:45 UTC35m
2026-07-05 CSS241 - Jul 5, 03:05 UTCJul 5, 06:35 UTC3h 30m
2026-07-04 CSS241 - Jul 4, 08:05 UTCJul 5, 06:35 UTC22h 30m
2026-07-04 CSS241 - Jul 4, 07:30 UTCJul 5, 06:00 UTC22h 30m
2026-07-04 CSS257 - Jul 4, 04:15 UTCJul 4, 05:40 UTC1h 25m
2026-07-03 CSS6801 SZX → EHU Jul 3, 17:50 UTCJul 3, 18:00 UTC10m
2026-07-03 CSS364 - Jul 3, 01:30 UTCJul 3, 03:10 UTC1h 40m
2026-07-02 CSS363 SZX → NRT Jul 2, 21:40 UTCJul 2, 23:10 UTC1h 30m
2026-07-02 CSS363 SZX → NRT Jul 2, 19:30 UTCJul 2, 19:40 UTC10m
2026-07-02 CSS335 - Jul 2, 05:40 UTCJul 2, 15:05 UTC9h 25m
2026-07-02 CSS335 - Jul 2, 04:50 UTCJul 2, 05:05 UTC15m
2026-06-30 CSS364 - Jun 30, 05:40 UTCJun 30, 06:00 UTC20m
2026-06-30 CSS364 - Jun 30, 01:19 UTCJun 30, 03:15 UTC1h 55m
2026-06-29 CSS363 SZX → NRT Jun 29, 21:39 UTCJun 29, 23:29 UTC1h 50m
2026-06-29 CSS364 - Jun 29, 02:25 UTCJun 29, 04:09 UTC1h 45m
2026-06-28 CSS363 SZX → NRT Jun 28, 21:40 UTCJun 28, 23:20 UTC1h 40m
2026-06-28 CSS363 SZX → NRT Jun 28, 19:29 UTCJun 28, 19:44 UTC15m
2026-06-28 CSS332 - Jun 28, 09:20 UTCJun 28, 12:19 UTC3h 0m
2026-06-28 CSS165 - Jun 28, 05:15 UTCJun 28, 07:44 UTC2h 30m
2026-06-27 CSS6801 SZX → EHU Jun 27, 21:34 UTCJun 27, 21:44 UTC10m
2026-06-27 CSS7223 - Jun 27, 19:05 UTCJun 27, 19:24 UTC20m
2026-06-25 CSS7103 - Jun 25, 16:45 UTCJun 25, 16:59 UTC15m
2026-06-24 CSS7103 - Jun 24, 16:59 UTCJun 24, 17:10 UTC10m
2026-06-22 CSS160 - Jun 22, 14:19 UTCJun 22, 16:24 UTC2h 5m
2026-06-21 CSS159 - Jun 21, 20:40 UTCJun 22, 12:40 UTC16h 0m
2026-06-21 CSS162 - Jun 21, 00:29 UTCJun 21, 18:20 UTC17h 50m
2026-06-20 CSS161 - Jun 20, 10:25 UTCJun 20, 22:14 UTC11h 50m
2026-06-20 CSS239 ZUH → DEL Jun 20, 04:14 UTCJun 20, 08:25 UTC4h 10m
2026-06-19 CSS240 - Jun 19, 20:19 UTCJun 19, 22:30 UTC2h 10m
2026-06-19 CSS159 - Jun 19, 16:04 UTCJun 19, 18:34 UTC2h 30m

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-221D page for operator, model, and routing details .

Mode-S 781C40 frequently asked

What is Mode-S code 781C40?
781C40 is an ICAO 24-bit transponder address. Allocated to China. Assigned to B-221D.
Where is Mode-S 781C40 registered?
Mode-S code 781C40 is allocated to China (CN). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 781C40 broadcasting right now?
Yes. Mode-S 781C40 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 781C40, octal 36016100, decimal 7,871,552.
What flights does 781C40 operate?
Mode-S 781C40 has broadcast 20 distinct callsigns, including CSS241, CSS363, CSS364, CSS242, CSS231.