sensors Mode-S transponder

A68D02

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N521DT · AIRBUS A-321neo · operated by DELTA AIR LINES INC

Hex
A68D02
Octal
51506402
Decimal
10,915,074
Country
US
Tail
N521DT
Type
A21N
No current signal · last broadcast 1d ago
Flights observed
7
Distinct callsigns
3
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S A68D02.

Country allocation

The ICAO 24-bit address A68D02 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 3 distinct

Callsign Airline Flights Last seen
DAL784 Delta Air Lines 4 2026-04-14
DAL548 - 2 2026-04-13
DAL795 Delta Air Lines 1 2026-04-12

Recent flights last 7

DateFlightRouteTakeoffLandingDuration
2026-04-14 DAL784 LGA → ORD Apr 14, 05:15 UTCApr 14, 07:00 UTC1h 45m
2026-04-13 DAL548 - Apr 13, 19:50 UTCApr 13, 20:55 UTC1h 5m
2026-04-13 DAL548 - Apr 13, 16:48 UTCApr 13, 20:55 UTC4h 7m
2026-04-13 DAL784 LGA → ORD Apr 13, 04:20 UTCApr 13, 07:10 UTC2h 50m
2026-04-13 DAL784 LGA → ORD Apr 13, 03:55 UTCApr 13, 07:10 UTC3h 15m
2026-04-13 DAL784 LGA → ORD Apr 13, 01:25 UTCApr 13, 06:29 UTC5h 4m
2026-04-12 DAL795 BOS → ORD Apr 12, 19:15 UTCApr 12, 20:15 UTC1h 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 N521DT page for operator, model, and routing details .

Mode-S A68D02 frequently asked

What is Mode-S code A68D02?
A68D02 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N521DT.
Where is Mode-S A68D02 registered?
Mode-S code A68D02 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 A68D02 broadcasting right now?
No active broadcast right now. Last signal was 1d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A68D02, octal 51506402, decimal 10,915,074.
What flights does A68D02 operate?
Mode-S A68D02 has broadcast 3 distinct callsigns, including DAL784, DAL548, DAL795.