Apparatus

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sensors Mode-S transponder

A68CFD

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N521DN · AIRBUS A-350-900 · operated by DELTA AIR LINES INC

Hex
A68CFD
Octal
51506375
Decimal
10,915,069
Country
US
Tail
N521DN
Type
A359
No current signal · last broadcast 2h ago
Flights observed
196
Distinct callsigns
20
Country
US
Last broadcast
2h ago

Last known position

Most recent position reported by Mode-S A68CFD.

Country allocation

The ICAO 24-bit address A68CFD falls within the block assigned to United States (US) by ICAO Annex 10, Volume III. Every aircraft registered in United States 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
DAL159 - 13 2026-06-23
DAL27 - 12 2026-07-13
DAL201 - 11 2026-07-04
DAL188 - 11 2026-07-07
DAL158 - 11 2026-07-14
DAL40 - 10 2026-06-15
DAL26 - 10 2026-06-26
DAL200 - 10 2026-07-03
DAL189 - 10 2026-07-06
DAL327 - 7 2026-07-12
DAL172 - 7 2026-06-24
DAL12 - 7 2026-07-12
DAL763 - 6 2026-07-11
DAL41 - 6 2026-06-15
DAL299 - 6 2026-07-02
DAL211 - 6 2026-07-05
DAL173 Delta Air Lines 6 2026-06-25
DAL1502 Delta Air Lines 6 2026-04-25
DAL11 - 6 2026-07-11
DAL39 Delta Air Lines 5 2026-05-18

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-14 DAL158 - Jul 14, 01:40 UTCJul 14, 03:30 UTC1h 50m
2026-07-13 DAL27 ATL → ICN Jul 13, 05:10 UTCJul 13, 19:15 UTC14h 5m
2026-07-12 DAL327 LAX → ATL Jul 12, 17:10 UTCJul 12, 21:00 UTC3h 50m
2026-07-12 DAL12 - Jul 12, 00:20 UTCJul 12, 13:50 UTC13h 30m
2026-07-11 DAL11 - Jul 11, 06:50 UTCJul 11, 21:50 UTC15h 0m
2026-07-11 DAL763 - Jul 11, 00:00 UTCJul 11, 03:50 UTC3h 50m
2026-07-10 DAL782 SLC → BOS Jul 10, 15:35 UTCJul 10, 19:15 UTC3h 40m
2026-07-10 DAL782 SLC → BOS Jul 10, 15:34 UTCJul 10, 19:41 UTC4h 7m
2026-07-10 DAL763 ATL → LAX Jul 10, 00:10 UTCJul 10, 04:15 UTC4h 5m
2026-07-09 DAL327 LAX → ATL Jul 9, 17:05 UTCJul 9, 21:15 UTC4h 10m
2026-07-09 DAL88 HKG → LAX Jul 9, 01:50 UTCJul 9, 14:50 UTC13h 0m
2026-07-08 DAL89 - Jul 8, 06:35 UTCJul 8, 07:40 UTC1h 5m
2026-07-08 DAL89 LAX → HKG Jul 8, 06:31 UTCJul 8, 20:42 UTC14h 11m
2026-07-08 DAL763 - Jul 8, 00:25 UTCJul 8, 04:10 UTC3h 45m
2026-07-07 DAL188 - Jul 7, 07:35 UTCJul 7, 09:15 UTC1h 40m
2026-07-07 DAL188 ICN → ATL Jul 7, 07:35 UTCJul 7, 20:56 UTC13h 21m
2026-07-07 DAL188 ICN → ATL Jul 7, 07:35 UTCJul 7, 20:50 UTC13h 15m
2026-07-06 DAL189 ATL → ICN Jul 6, 14:10 UTCJul 7, 04:30 UTC14h 20m
2026-07-06 DAL189 ATL → ICN Jul 6, 14:07 UTCJul 7, 04:33 UTC14h 26m
2026-07-05 DAL211 - Jul 5, 18:30 UTCJul 5, 18:55 UTC25m
2026-07-05 DAL211 CPT → ATL Jul 5, 18:30 UTCJul 6, 10:08 UTC15h 38m
2026-07-05 DAL211 CPT → ATL Jul 5, 18:30 UTCJul 6, 10:10 UTC15h 40m
2026-07-05 DAL210 - Jul 5, 02:05 UTCJul 5, 02:50 UTC45m
2026-07-05 DAL210 ATL → CPT Jul 5, 02:03 UTCJul 5, 16:04 UTC14h 1m
2026-07-04 DAL201 - Jul 4, 11:05 UTCJul 4, 12:00 UTC55m
2026-07-03 DAL201 - Jul 3, 20:05 UTCJul 4, 04:15 UTC8h 10m
2026-07-03 DAL200 - Jul 3, 02:40 UTCJul 3, 03:30 UTC50m
2026-07-03 DAL200 ATL → JNB Jul 3, 02:39 UTCJul 3, 17:06 UTC14h 27m
2026-07-02 DAL299 - Jul 2, 13:35 UTCJul 2, 16:05 UTC2h 30m
2026-07-02 DAL299 FCO → ATL Jul 2, 13:31 UTCJul 2, 23:27 UTC9h 56m
2026-07-02 DAL299 FCO → ATL Jul 2, 13:31 UTCJul 2, 23:31 UTC10h 0m
2026-07-02 DAL298 - Jul 2, 01:45 UTCJul 2, 10:50 UTC9h 5m
2026-07-01 DAL327 LAX → ATL Jul 1, 18:10 UTCJul 1, 22:15 UTC4h 5m
2026-07-01 DAL12 MEL → LAX Jul 1, 01:53 UTCJul 1, 15:22 UTC13h 29m
2026-07-01 DAL12 - Jul 1, 01:55 UTCJul 1, 03:00 UTC1h 5m
2026-06-30 DAL11 LHR → MSP Jun 30, 07:53 UTCJun 30, 23:24 UTC15h 31m
2026-06-30 DAL11 LHR → MSP Jun 30, 07:55 UTCJun 30, 08:25 UTC30m
2026-06-30 DAL763 ATL → LAX Jun 30, 00:00 UTCJun 30, 04:10 UTC4h 11m
2026-06-29 DAL188 ICN → ATL Jun 29, 07:40 UTCJun 29, 20:40 UTC13h 0m
2026-06-28 DAL189 ATL → ICN Jun 28, 14:09 UTCJun 29, 04:35 UTC14h 26m
2026-06-28 DAL189 - Jun 28, 14:09 UTCJun 28, 21:50 UTC7h 40m
2026-06-26 DAL26 ICN → ATL Jun 26, 10:05 UTCJun 26, 23:15 UTC13h 10m
2026-06-25 DAL173 MXP → JFK Jun 25, 17:39 UTCJun 26, 05:44 UTC12h 5m
2026-06-24 DAL172 ICN → SLC Jun 24, 10:26 UTCJun 24, 20:51 UTC10h 25m
2026-06-24 DAL172 ICN → SLC Jun 24, 10:30 UTCJun 24, 20:49 UTC10h 20m
2026-06-23 DAL159 - Jun 23, 17:09 UTCJun 23, 19:15 UTC2h 5m
2026-06-23 DAL159 DTW → ICN Jun 23, 17:09 UTCJun 24, 06:52 UTC13h 43m
2026-06-23 DAL158 - Jun 23, 01:40 UTCJun 23, 13:45 UTC12h 5m
2026-06-22 DAL27 ATL → ICN Jun 22, 04:00 UTCJun 22, 18:15 UTC14h 15m
2026-06-21 DAL26 - Jun 21, 21:49 UTCJun 22, 01:49 UTC4h 0m

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 N521DN page for operator, model, and routing details .

Mode-S A68CFD frequently asked

What is Mode-S code A68CFD?
A68CFD is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N521DN.
Where is Mode-S A68CFD registered?
Mode-S code A68CFD is allocated to United States (US). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is A68CFD 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 A68CFD, octal 51506375, decimal 10,915,069.
What flights does A68CFD operate?
Mode-S A68CFD has broadcast 20 distinct callsigns, including DAL159, DAL27, DAL201, DAL188, DAL158.