Apparatus

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sensors Mode-S transponder

458D99

ICAO 24-bit transponder address · allocated to Denmark

Currently assigned to OY-CLY · ATR-72-500

Hex
458D99
Octal
21306631
Decimal
4,558,233
Country
DK
Tail
OY-CLY
Type
AT75
No current signal · last broadcast 13h ago
Flights observed
187
Distinct callsigns
20
Country
DK
Last broadcast
13h ago

Last known position

Most recent position reported by Mode-S 458D99.

Country allocation

The ICAO 24-bit address 458D99 falls within the block assigned to Denmark (DK) by ICAO Annex 10, Volume III. Every aircraft registered in Denmark 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
MMD352 Air Alsie 16 2026-05-29
MMD101 Air Alsie 15 2026-05-29
MMD108 Air Alsie 14 2026-05-28
MMD358 Air Alsie 13 2026-05-29
MMD107 Air Alsie 13 2026-05-28
MMD106 Air Alsie 13 2026-05-28
MMD359 Air Alsie 12 2026-05-28
MMD353 Air Alsie 12 2026-05-29
MMD110 Air Alsie 12 2026-05-28
MMD109 Air Alsie 10 2026-05-26
MMD102 Air Alsie 10 2026-05-27
MMD354 Air Alsie 9 2026-05-27
MMD103 Air Alsie 9 2026-05-27
MMD357 Air Alsie 8 2026-05-20
MMD105 Air Alsie 4 2026-05-18
MMD104 Air Alsie 4 2026-05-18
MMD121 Air Alsie 3 2026-05-17
MMD116 Air Alsie 3 2026-05-16
MMD115 Air Alsie 3 2026-05-16
MMD351 Air Alsie 2 2026-05-10

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-05-29 MMD352 CPH → KRP May 29, 15:50 UTCMay 29, 16:25 UTC35m
2026-05-29 MMD353 KRP → CPH May 29, 14:30 UTCMay 29, 15:10 UTC40m
2026-05-29 MMD358 CPH → KRP May 29, 06:15 UTCMay 29, 06:50 UTC35m
2026-05-29 MMD101 SGD → CPH May 29, 05:05 UTCMay 29, 05:35 UTC30m
2026-05-28 MMD110 CPH → SGD May 28, 20:10 UTCMay 28, 20:45 UTC35m
2026-05-28 MMD108 CPH → SGD May 28, 16:20 UTCMay 28, 17:50 UTC1h 30m
2026-05-28 MMD107 SGD → CPH May 28, 14:45 UTCMay 28, 15:15 UTC30m
2026-05-28 MMD106 CPH → SGD May 28, 13:20 UTCMay 28, 13:50 UTC30m
2026-05-28 MMD358 CPH → KRP May 28, 06:45 UTCMay 28, 08:30 UTC1h 45m
2026-05-28 MMD359 KRP → CPH May 28, 05:10 UTCMay 28, 05:45 UTC35m
2026-05-27 MMD352 CPH → KRP May 27, 16:40 UTCMay 27, 17:20 UTC40m
2026-05-27 MMD353 KRP → CPH May 27, 15:10 UTCMay 27, 15:40 UTC30m
2026-05-27 MMD354 CPH → KRP May 27, 13:55 UTCMay 27, 14:35 UTC40m
2026-05-27 MMD103 SGD → CPH May 27, 07:35 UTCMay 27, 08:05 UTC30m
2026-05-27 MMD102 CPH → SGD May 27, 06:25 UTCMay 27, 06:55 UTC30m
2026-05-27 MMD101 SGD → CPH May 27, 05:04 UTCMay 27, 05:35 UTC30m
2026-05-26 MMD110 CPH → SGD May 26, 20:00 UTCMay 26, 20:34 UTC35m
2026-05-26 MMD109 SGD → CPH May 26, 17:20 UTCMay 26, 17:44 UTC25m
2026-05-26 MMD108 CPH → SGD May 26, 16:10 UTCMay 26, 16:40 UTC30m
2026-05-26 MMD107 SGD → CPH May 26, 14:50 UTCMay 26, 15:24 UTC35m
2026-05-26 MMD106 CPH → SGD May 26, 13:24 UTCMay 26, 14:00 UTC35m
2026-05-26 MMD358 CPH → KRP May 26, 06:29 UTCMay 26, 08:15 UTC1h 45m
2026-05-26 MMD359 KRP → CPH May 26, 05:05 UTCMay 26, 05:40 UTC35m
2026-05-22 MMD352 CPH → KRP May 22, 15:45 UTCMay 22, 16:20 UTC35m
2026-05-22 MMD353 KRP → CPH May 22, 14:05 UTCMay 22, 14:45 UTC40m
2026-05-22 MMD358 CPH → KRP May 22, 06:15 UTCMay 22, 06:50 UTC35m
2026-05-22 MMD359 KRP → CPH May 22, 05:00 UTCMay 22, 05:35 UTC35m
2026-05-21 MMD352 CPH → KRP May 21, 16:35 UTCMay 21, 17:15 UTC40m
2026-05-21 MMD353 KRP → CPH May 21, 15:10 UTCMay 21, 15:40 UTC30m
2026-05-21 MMD354 CPH → KRP May 21, 13:50 UTCMay 21, 14:30 UTC40m
2026-05-21 MMD103 SGD → CPH May 21, 07:40 UTCMay 21, 08:10 UTC30m
2026-05-21 MMD102 CPH → SGD May 21, 06:30 UTCMay 21, 07:00 UTC30m
2026-05-21 MMD101 SGD → CPH May 21, 05:05 UTCMay 21, 05:35 UTC30m
2026-05-20 MMD110 CPH → SGD May 20, 20:05 UTCMay 20, 20:40 UTC35m
2026-05-20 MMD109 SGD → CPH May 20, 17:20 UTCMay 20, 17:50 UTC30m
2026-05-20 MMD108 CPH → SGD May 20, 16:10 UTCMay 20, 16:45 UTC35m
2026-05-20 MMD107 SGD → CPH May 20, 14:50 UTCMay 20, 15:25 UTC35m
2026-05-20 MMD106 CPH → SGD May 20, 13:25 UTCMay 20, 13:55 UTC30m
2026-05-20 MMD357 KRP → CPH May 20, 07:35 UTCMay 20, 08:10 UTC35m
2026-05-20 MMD358 CPH → KRP May 20, 06:25 UTCMay 20, 06:55 UTC30m
2026-05-20 MMD359 KRP → CPH May 20, 05:05 UTCMay 20, 05:40 UTC35m
2026-05-19 MMD352 CPH → KRP May 19, 16:40 UTCMay 19, 17:10 UTC30m
2026-05-19 MMD353 KRP → CPH May 19, 15:05 UTCMay 19, 15:40 UTC35m
2026-05-19 MMD354 CPH → KRP May 19, 13:55 UTCMay 19, 14:25 UTC30m
2026-05-19 MMD103 SGD → CPH May 19, 06:35 UTCMay 19, 08:10 UTC1h 35m
2026-05-19 MMD101 SGD → CPH May 19, 05:05 UTCMay 19, 05:35 UTC30m
2026-05-18 MMD108 CPH → SGD May 18, 16:20 UTCMay 18, 16:50 UTC30m
2026-05-18 MMD107 SGD → CPH May 18, 14:50 UTCMay 18, 15:25 UTC35m
2026-05-18 MMD106 CPH → SGD May 18, 13:30 UTCMay 18, 14:00 UTC30m
2026-05-18 MMD105 SGD → CPH May 18, 11:35 UTCMay 18, 12:05 UTC30m

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 OY-CLY page for operator, model, and routing details .

Mode-S 458D99 frequently asked

What is Mode-S code 458D99?
458D99 is an ICAO 24-bit transponder address. Allocated to Denmark. Assigned to OY-CLY.
Where is Mode-S 458D99 registered?
Mode-S code 458D99 is allocated to Denmark (DK). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 458D99 broadcasting right now?
No active broadcast right now. Last signal was 13h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 458D99, octal 21306631, decimal 4,558,233.
What flights does 458D99 operate?
Mode-S 458D99 has broadcast 20 distinct callsigns, including MMD352, MMD101, MMD108, MMD358, MMD107.