Apparatus

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sensors Mode-S transponder

781DC6

ICAO 24-bit transponder address · allocated to China

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

Hex
781DC6
Octal
36016706
Decimal
7,871,942
Country
CN
Tail
B-221X
Type
B77L
No current signal · last broadcast 10h ago
Flights observed
146
Distinct callsigns
7
Country
CN
Last broadcast
10h ago

Last known position

Most recent position reported by Mode-S 781DC6.

Country allocation

The ICAO 24-bit address 781DC6 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 7 distinct

Callsign Airline Flights Last seen
CYZ257 - 60 2026-07-12
CYZ258 - 26 2026-07-17
CYZ255 China Postal Airlines 20 2026-07-17
CYZ256 - 18 2026-07-15
CYZ294 - 9 2026-05-13
CYZ237 - 8 2026-05-12
CYZ278 - 5 2026-05-09

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-17 CYZ258 - Jul 17, 11:25 UTCJul 17, 17:40 UTC6h 15m
2026-07-17 CYZ255 NKG → LUX Jul 17, 05:35 UTCJul 17, 05:55 UTC20m
2026-07-16 CYZ255 - Jul 16, 23:29 UTCJul 17, 02:54 UTC3h 25m
2026-07-15 CYZ256 - Jul 15, 10:00 UTCJul 15, 16:20 UTC6h 20m
2026-07-14 CYZ255 - Jul 14, 23:40 UTCJul 15, 03:10 UTC3h 30m
2026-07-13 CYZ256 - Jul 13, 12:55 UTCJul 13, 19:05 UTC6h 10m
2026-07-12 CYZ257 - Jul 12, 14:25 UTCJul 13, 09:25 UTC19h 0m
2026-07-12 CYZ257 - Jul 12, 09:35 UTCJul 13, 09:25 UTC23h 50m
2026-07-12 CYZ258 - Jul 12, 08:50 UTCJul 13, 07:30 UTC22h 40m
2026-07-11 CYZ257 - Jul 11, 22:30 UTCJul 12, 04:55 UTC6h 25m
2026-07-10 CYZ258 - Jul 10, 10:00 UTCJul 10, 16:10 UTC6h 10m
2026-07-09 CYZ255 - Jul 9, 23:10 UTCJul 10, 05:35 UTC6h 25m
2026-07-08 CYZ256 - Jul 8, 10:05 UTCJul 8, 16:20 UTC6h 15m
2026-07-07 CYZ255 - Jul 7, 23:30 UTCJul 8, 06:00 UTC6h 30m
2026-07-06 CYZ256 - Jul 6, 13:05 UTCJul 6, 19:25 UTC6h 20m
2026-07-05 CYZ257 - Jul 5, 14:45 UTCJul 6, 09:10 UTC18h 25m
2026-07-05 CYZ257 - Jul 5, 11:35 UTCJul 6, 09:10 UTC21h 35m
2026-07-05 CYZ257 - Jul 5, 09:35 UTCJul 6, 09:10 UTC23h 35m
2026-07-05 CYZ258 - Jul 5, 09:10 UTCJul 6, 07:30 UTC22h 20m
2026-07-04 CYZ257 - Jul 4, 22:55 UTCJul 5, 05:35 UTC6h 40m
2026-07-03 CYZ258 - Jul 3, 09:50 UTCJul 3, 15:50 UTC6h 0m
2026-07-02 CYZ255 - Jul 2, 23:40 UTCJul 3, 06:35 UTC6h 55m
2026-07-01 CYZ256 - Jul 1, 10:15 UTCJul 1, 16:10 UTC5h 55m
2026-06-30 CYZ255 - Jun 30, 23:20 UTCJul 1, 06:05 UTC6h 45m
2026-06-29 CYZ256 - Jun 29, 13:14 UTCJun 29, 19:15 UTC6h 0m
2026-06-29 CYZ257 - Jun 29, 00:20 UTCJun 29, 09:44 UTC9h 25m
2026-06-28 CYZ257 - Jun 28, 14:30 UTCJun 29, 09:44 UTC19h 15m
2026-06-28 CYZ257 - Jun 28, 11:59 UTCJun 29, 09:44 UTC21h 45m
2026-06-28 CYZ257 - Jun 28, 09:34 UTCJun 29, 09:29 UTC23h 55m
2026-06-28 CYZ258 - Jun 28, 08:50 UTCJun 29, 06:09 UTC21h 20m
2026-06-27 CYZ257 - Jun 27, 23:00 UTCJun 28, 05:24 UTC6h 25m
2026-06-26 CYZ258 - Jun 26, 14:50 UTCJun 26, 21:04 UTC6h 15m
2026-06-26 CYZ255 - Jun 26, 04:14 UTCJun 26, 10:39 UTC6h 25m
2026-06-24 CYZ256 - Jun 24, 10:14 UTCJun 24, 16:34 UTC6h 20m
2026-06-23 CYZ255 - Jun 23, 23:24 UTCJun 24, 05:40 UTC6h 15m
2026-06-22 CYZ256 - Jun 22, 13:05 UTCJun 22, 19:19 UTC6h 15m
2026-06-21 CYZ257 - Jun 21, 14:19 UTCJun 22, 09:14 UTC18h 55m
2026-06-21 CYZ257 - Jun 21, 09:35 UTCJun 22, 09:14 UTC23h 40m
2026-06-21 CYZ258 - Jun 21, 09:00 UTCJun 22, 07:30 UTC22h 30m
2026-06-20 CYZ257 - Jun 20, 22:45 UTCJun 21, 05:20 UTC6h 35m
2026-06-19 CYZ258 - Jun 19, 09:59 UTCJun 19, 16:14 UTC6h 15m
2026-06-18 CYZ255 - Jun 18, 23:20 UTCJun 19, 05:49 UTC6h 29m
2026-06-17 CYZ256 - Jun 17, 10:00 UTCJun 17, 16:15 UTC6h 15m
2026-06-16 CYZ255 - Jun 16, 23:20 UTCJun 17, 05:30 UTC6h 10m
2026-06-15 CYZ256 LUX → NKG Jun 15, 12:35 UTCJun 15, 19:05 UTC6h 30m
2026-06-14 CYZ257 - Jun 14, 14:50 UTCJun 15, 09:05 UTC18h 14m
2026-06-14 CYZ257 - Jun 14, 12:25 UTCJun 15, 09:05 UTC20h 39m
2026-06-14 CYZ257 - Jun 14, 09:35 UTCJun 15, 09:05 UTC23h 29m
2026-06-14 CYZ258 - Jun 14, 09:00 UTCJun 15, 07:29 UTC22h 29m
2026-06-13 CYZ257 - Jun 13, 22:50 UTCJun 14, 05:05 UTC6h 15m

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

Mode-S 781DC6 frequently asked

What is Mode-S code 781DC6?
781DC6 is an ICAO 24-bit transponder address. Allocated to China. Assigned to B-221X.
Where is Mode-S 781DC6 registered?
Mode-S code 781DC6 is allocated to China (CN). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 781DC6 broadcasting right now?
No active broadcast right now. Last signal was 10h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 781DC6, octal 36016706, decimal 7,871,942.
What flights does 781DC6 operate?
Mode-S 781DC6 has broadcast 7 distinct callsigns, including CYZ257, CYZ258, CYZ255, CYZ256, CYZ294.