Apparatus

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sensors Mode-S transponder

3C4B21

ICAO 24-bit transponder address · allocated to Germany

Currently assigned to D-ABYA · BOEING 747-8

Hex
3C4B21
Octal
17045441
Decimal
3,951,393
Country
DE
Tail
D-ABYA
Type
B748
No current signal · last broadcast 2h ago
Flights observed
123
Distinct callsigns
20
Country
DE
Last broadcast
2h ago

Last known position

Most recent position reported by Mode-S 3C4B21.

Country allocation

The ICAO 24-bit address 3C4B21 falls within the block assigned to Germany (DE) by ICAO Annex 10, Volume III. Every aircraft registered in Germany 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
DLH463 - 13 2026-07-06
DLH462 Lufthansa 11 2026-07-06
DLH506 - 10 2026-07-16
DLH431 - 10 2026-07-05
DLH430 Lufthansa 10 2026-07-05
DLH507 - 9 2026-07-17
DLH499 Lufthansa 6 2026-06-08
DLH498 Lufthansa 6 2026-06-07
DLH402 - 6 2026-06-30
DLH457 - 5 2026-06-27
DLH456 Lufthansa 5 2026-06-27
DLH403 - 5 2026-06-30
DLH573 Lufthansa 4 2026-06-21
DLH7K - 3 2026-07-09
DLH572 - 3 2026-06-20
DLH423 - 3 2026-07-09
DLH754 Lufthansa 2 2026-05-19
DLH455 - 2 2026-06-29
DLH454 Lufthansa 2 2026-06-29
DLH419 - 2 2026-06-24

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-17 DLH507 - Jul 17, 21:44 UTCJul 18, 00:29 UTC2h 45m
2026-07-16 DLH506 FRA → GRU Jul 16, 20:45 UTCJul 17, 08:15 UTC11h 30m
2026-07-09 DLH423 BOS → FRA Jul 9, 22:20 UTCJul 10, 04:35 UTC6h 15m
2026-07-09 DLH7K FRA → BOS Jul 9, 11:55 UTCJul 9, 19:15 UTC7h 20m
2026-07-08 DLH507 - Jul 8, 21:45 UTCJul 9, 08:30 UTC10h 45m
2026-07-07 DLH506 FRA → GRU Jul 7, 20:40 UTCJul 8, 07:50 UTC11h 10m
2026-07-06 DLH463 - Jul 6, 21:25 UTCJul 7, 05:55 UTC8h 30m
2026-07-06 DLH462 FRA → MIA Jul 6, 09:15 UTCJul 6, 18:20 UTC9h 5m
2026-07-05 DLH431 ORD → FRA Jul 5, 22:05 UTCJul 6, 05:20 UTC7h 15m
2026-07-05 DLH430 FRA → ORD Jul 5, 09:55 UTCJul 5, 18:20 UTC8h 25m
2026-07-04 DLH463 - Jul 4, 21:00 UTCJul 5, 05:20 UTC8h 20m
2026-07-04 DLH462 FRA → MIA Jul 4, 09:15 UTCJul 4, 18:25 UTC9h 10m
2026-07-03 DLH423 BOS → FRA Jul 3, 22:40 UTCJul 4, 05:00 UTC6h 20m
2026-07-03 DLH7K FRA → BOS Jul 3, 12:10 UTCJul 3, 19:35 UTC7h 25m
2026-06-30 DLH403 EWR → FRA Jun 30, 22:40 UTCJul 1, 05:20 UTC6h 40m
2026-06-30 DLH402 FRA → EWR Jun 30, 12:15 UTCJun 30, 19:55 UTC7h 40m
2026-06-29 DLH455 SFO → FRA Jun 29, 22:10 UTCJun 30, 08:10 UTC10h 0m
2026-06-29 DLH454 FRA → SFO Jun 29, 09:00 UTCJun 29, 19:09 UTC10h 10m
2026-06-27 DLH457 - Jun 27, 22:49 UTCJun 28, 09:05 UTC10h 15m
2026-06-27 DLH456 FRA → LAX Jun 27, 10:00 UTCJun 27, 20:44 UTC10h 45m
2026-06-25 DLH463 - Jun 25, 22:34 UTCJun 26, 06:39 UTC8h 5m
2026-06-25 DLH462 FRA → MIA Jun 25, 09:34 UTCJun 25, 18:50 UTC9h 15m
2026-06-24 DLH419 IAD → FRA Jun 24, 22:35 UTCJun 25, 05:25 UTC6h 50m
2026-06-24 DLH3W FRA → IAD Jun 24, 11:54 UTCJun 24, 20:09 UTC8h 15m
2026-06-23 DLH419 IAD → FRA Jun 23, 23:29 UTCJun 24, 06:20 UTC6h 50m
2026-06-23 DLH3W - Jun 23, 11:29 UTCJun 23, 20:19 UTC8h 50m
2026-06-22 DLH463 - Jun 22, 22:10 UTCJun 23, 06:24 UTC8h 15m
2026-06-22 DLH462 FRA → MIA Jun 22, 09:54 UTCJun 22, 19:14 UTC9h 20m
2026-06-21 DLH573 JNB → FRA Jun 21, 17:20 UTCJun 22, 03:14 UTC9h 55m
2026-06-20 DLH572 - Jun 20, 20:40 UTCJun 21, 06:40 UTC10h 0m
2026-06-19 DLH403 - Jun 19, 23:14 UTCJun 20, 05:44 UTC6h 30m
2026-06-19 DLH402 FRA → EWR Jun 19, 12:19 UTCJun 19, 20:14 UTC7h 55m
2026-06-18 DLH403 EWR → FRA Jun 18, 22:55 UTCJun 19, 05:40 UTC6h 44m
2026-06-18 DLH402 - Jun 18, 18:35 UTCJun 18, 20:10 UTC1h 35m
2026-06-18 DLH402 - Jun 18, 12:25 UTCJun 18, 18:30 UTC6h 5m
2026-06-17 DLH455 SFO → FRA Jun 17, 22:45 UTCJun 18, 08:55 UTC10h 10m
2026-06-17 DLH454 FRA → SFO Jun 17, 09:25 UTCJun 17, 20:10 UTC10h 45m
2026-06-16 DLH431 - Jun 16, 22:30 UTCJun 17, 05:55 UTC7h 25m
2026-06-16 DLH430 FRA → ORD Jun 16, 09:34 UTCJun 16, 18:05 UTC8h 30m
2026-06-15 DLH463 - Jun 15, 21:40 UTCJun 16, 05:55 UTC8h 15m
2026-06-15 DLH462 FRA → MIA Jun 15, 09:45 UTCJun 15, 19:14 UTC9h 30m
2026-06-13 DLH403 - Jun 13, 22:40 UTCJun 14, 05:20 UTC6h 40m
2026-06-13 DLH402 FRA → EWR Jun 13, 11:55 UTCJun 13, 19:50 UTC7h 55m
2026-06-13 DLH403 EWR → FRA Jun 13, 00:10 UTCJun 13, 07:00 UTC6h 49m
2026-06-12 DLH402 FRA → EWR Jun 12, 12:10 UTCJun 12, 20:05 UTC7h 55m
2026-06-11 DLH507 GRU → FRA Jun 11, 22:05 UTCJun 12, 08:50 UTC10h 46m
2026-06-10 DLH506 FRA → GRU Jun 10, 20:45 UTCJun 11, 07:55 UTC11h 10m
2026-06-09 DLH511 EZE → FRA Jun 9, 19:35 UTCJun 10, 07:50 UTC12h 15m
2026-06-08 DLH510 FRA → EZE Jun 8, 20:35 UTCJun 9, 09:55 UTC13h 20m
2026-06-08 DLH499 MEX → FRA Jun 8, 02:30 UTCJun 8, 12:35 UTC10h 5m

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

Mode-S 3C4B21 frequently asked

What is Mode-S code 3C4B21?
3C4B21 is an ICAO 24-bit transponder address. Allocated to Germany. Assigned to D-ABYA.
Where is Mode-S 3C4B21 registered?
Mode-S code 3C4B21 is allocated to Germany (DE). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 3C4B21 broadcasting right now?
No active broadcast right now. Last signal was 2h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 3C4B21, octal 17045441, decimal 3,951,393.
What flights does 3C4B21 operate?
Mode-S 3C4B21 has broadcast 20 distinct callsigns, including DLH463, DLH462, DLH506, DLH431, DLH430.