Apparatus

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sensors Mode-S transponder

781D6D

ICAO 24-bit transponder address · allocated to China

Currently assigned to B-221S · BOEING 777-200LR

Hex
781D6D
Octal
36016555
Decimal
7,871,853
Country
CN
Tail
B-221S
Type
B77L
No current signal · last broadcast 22h ago
Flights observed
206
Distinct callsigns
20
Country
CN
Last broadcast
22h ago

Last known position

Most recent position reported by Mode-S 781D6D.

Country allocation

The ICAO 24-bit address 781D6D 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
CKK225 - 22 2026-07-09
CKK221 - 20 2026-07-15
CKK621 China Cargo Airlines 13 2026-07-19
CKK205 - 12 2026-07-13
CKK226 - 10 2026-06-23
CKK206 - 10 2026-07-13
CKK294 China Cargo Airlines 9 2026-06-07
CKK231 - 9 2026-07-11
CKK223 China Cargo Airlines 9 2026-05-28
CKK227 China Cargo Airlines 8 2026-05-31
CKK224 China Cargo Airlines 7 2026-05-29
CKK222 - 7 2026-07-16
CKK232 - 6 2026-07-12
CKK215 China Cargo Airlines 6 2026-07-17
CKK622 China Cargo Airlines 5 2026-07-19
CKK602 - 5 2026-07-21
CKK287 China Cargo Airlines 5 2026-05-27
CKK235 - 5 2026-07-21
CKK228 China Cargo Airlines 5 2026-06-01
CKK216 - 5 2026-07-17

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-22 CKK236 LAX → CKG Jul 22, 12:15 UTCJul 22, 18:10 UTC5h 55m
2026-07-21 CKK235 - Jul 21, 11:25 UTCJul 22, 05:25 UTC18h 0m
2026-07-21 CKK602 - Jul 21, 09:20 UTCJul 22, 05:25 UTC20h 5m
2026-07-21 CKK602 - Jul 21, 08:20 UTCJul 22, 05:25 UTC21h 5m
2026-07-21 CKK601 - Jul 21, 01:50 UTCJul 21, 05:05 UTC3h 15m
2026-07-19 CKK622 YYZ → CKG Jul 19, 16:20 UTCJul 19, 16:55 UTC35m
2026-07-19 CKK621 CKG → ANC Jul 19, 07:45 UTCJul 19, 13:15 UTC5h 30m
2026-07-18 CKK621 CKG → ANC Jul 18, 23:00 UTCJul 19, 06:10 UTC7h 10m
2026-07-18 CKK621 CKG → ANC Jul 18, 09:25 UTCJul 19, 06:10 UTC20h 45m
2026-07-17 CKK216 FRA → ICN Jul 17, 12:25 UTCJul 18, 07:05 UTC18h 41m
2026-07-17 CKK215 PVG → CDG Jul 17, 03:05 UTCJul 17, 09:20 UTC6h 15m
2026-07-16 CKK215 PVG → CDG Jul 16, 11:20 UTCJul 17, 09:20 UTC22h 0m
2026-07-16 CKK215 PVG → CDG Jul 16, 10:40 UTCJul 17, 09:15 UTC22h 35m
2026-07-16 CKK222 - Jul 16, 00:55 UTCJul 16, 12:30 UTC11h 35m
2026-07-15 CKK221 - Jul 15, 11:05 UTCJul 15, 22:20 UTC11h 15m
2026-07-15 CKK221 - Jul 15, 01:20 UTCJul 15, 22:20 UTC21h 0m
2026-07-14 CKK241 - Jul 14, 21:10 UTCJul 14, 22:55 UTC1h 44m
2026-07-14 CKK241 - Jul 14, 01:20 UTCJul 14, 22:55 UTC21h 34m
2026-07-14 CKK241 - Jul 14, 00:50 UTCJul 14, 22:55 UTC22h 4m
2026-07-13 CKK206 - Jul 13, 21:20 UTCJul 14, 21:15 UTC23h 55m
2026-07-13 CKK206 - Jul 13, 19:25 UTCJul 14, 01:25 UTC6h 0m
2026-07-13 CKK205 - Jul 13, 04:25 UTCJul 13, 13:55 UTC9h 30m
2026-07-12 CKK205 - Jul 12, 15:20 UTCJul 13, 13:55 UTC22h 35m
2026-07-12 CKK205 - Jul 12, 13:40 UTCJul 13, 13:15 UTC23h 35m
2026-07-12 CKK232 - Jul 12, 07:20 UTCJul 13, 04:35 UTC21h 15m
2026-07-12 CKK232 - Jul 12, 07:01 UTCJul 13, 04:35 UTC21h 35m
2026-07-12 CKK232 - Jul 12, 00:55 UTCJul 12, 15:20 UTC14h 25m
2026-07-11 CKK231 ANC → JFK Jul 11, 14:30 UTCJul 11, 20:50 UTC6h 20m
2026-07-10 CKK231 - Jul 10, 20:45 UTCJul 11, 13:05 UTC16h 20m
2026-07-10 CKK231 - Jul 10, 14:40 UTCJul 11, 13:05 UTC22h 25m
2026-07-10 CKK231 - Jul 10, 09:20 UTCJul 11, 07:00 UTC21h 40m
2026-07-10 CKK226A - Jul 10, 08:45 UTCJul 11, 07:00 UTC22h 15m
2026-07-09 CKK225 ANC → ORD Jul 9, 23:45 UTCJul 10, 05:20 UTC5h 35m
2026-07-09 CKK225 - Jul 9, 13:05 UTCJul 9, 20:55 UTC7h 50m
2026-07-08 CKK222 - Jul 8, 00:00 UTCJul 8, 12:05 UTC12h 5m
2026-07-07 CKK221 PVG → LAX Jul 7, 10:35 UTCJul 7, 21:20 UTC10h 45m
2026-07-06 CKK221 PVG → LAX Jul 6, 22:45 UTCJul 7, 21:15 UTC22h 30m
2026-07-06 CKK221 PVG → LAX Jul 6, 16:40 UTCJul 7, 12:20 UTC19h 40m
2026-07-06 CKK221 PVG → LAX Jul 6, 13:20 UTCJul 7, 12:20 UTC23h 0m
2026-07-06 CKK232 - Jul 6, 10:00 UTCJul 6, 22:55 UTC12h 55m
2026-07-05 CKK231 ANC → JFK Jul 5, 19:40 UTCJul 6, 02:35 UTC6h 55m
2026-07-05 CKK231 - Jul 5, 10:50 UTCJul 5, 18:15 UTC7h 25m
2026-07-04 CKK231 - Jul 4, 19:55 UTCJul 5, 18:15 UTC22h 20m
2026-07-04 CKK204 - Jul 4, 13:20 UTCJul 5, 12:15 UTC22h 55m
2026-07-04 CKK204 - Jul 4, 11:20 UTCJul 5, 11:15 UTC23h 55m
2026-07-04 CKK204 - Jul 4, 11:00 UTCJul 4, 20:15 UTC9h 15m
2026-07-03 CKK203 - Jul 3, 21:55 UTCJul 4, 07:45 UTC9h 50m
2026-07-01 CKK622 - Jul 1, 16:40 UTCJul 1, 19:30 UTC2h 50m
2026-07-01 CKK621 ANC → YYZ Jul 1, 08:05 UTCJul 1, 13:45 UTC5h 40m
2026-06-30 CKK621 - Jun 30, 13:45 UTCJul 1, 06:20 UTC16h 35m

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

Mode-S 781D6D frequently asked

What is Mode-S code 781D6D?
781D6D is an ICAO 24-bit transponder address. Allocated to China. Assigned to B-221S.
Where is Mode-S 781D6D registered?
Mode-S code 781D6D is allocated to China (CN). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 781D6D broadcasting right now?
No active broadcast right now. Last signal was 22h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 781D6D, octal 36016555, decimal 7,871,853.
What flights does 781D6D operate?
Mode-S 781D6D has broadcast 20 distinct callsigns, including CKK225, CKK221, CKK621, CKK205, CKK226.