sensors Mode-S transponder

A6DBF3

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N541DE · AIRBUS A-321neo · operated by DELTA AIR LINES INC

Hex
A6DBF3
Octal
51555763
Decimal
10,935,283
Country
US
Tail
N541DE
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 A6DBF3.

Country allocation

The ICAO 24-bit address A6DBF3 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
DAL694 Delta Air Lines 3 2026-04-13
DAL515 - 3 2026-04-13
DAL459 Delta Air Lines 1 2026-04-12

Recent flights last 7

DateFlightRouteTakeoffLandingDuration
2026-04-13 DAL515 - Apr 13, 16:15 UTCApr 13, 18:05 UTC1h 50m
2026-04-13 DAL515 - Apr 13, 15:50 UTCApr 13, 18:05 UTC2h 15m
2026-04-13 DAL515 - Apr 13, 14:29 UTCApr 13, 18:11 UTC3h 42m
2026-04-13 DAL694 SEA → CVG Apr 13, 04:20 UTCApr 13, 06:00 UTC1h 40m
2026-04-13 DAL694 SEA → CVG Apr 13, 03:55 UTCApr 13, 06:00 UTC2h 5m
2026-04-13 DAL694 SEA → CVG Apr 13, 01:20 UTCApr 13, 04:15 UTC2h 55m
2026-04-12 DAL459 JFK → SAN Apr 12, 17:15 UTCApr 12, 19:40 UTC2h 25m

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 N541DE page for operator, model, and routing details .

Mode-S A6DBF3 frequently asked

What is Mode-S code A6DBF3?
A6DBF3 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N541DE.
Where is Mode-S A6DBF3 registered?
Mode-S code A6DBF3 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 A6DBF3 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 A6DBF3, octal 51555763, decimal 10,935,283.
What flights does A6DBF3 operate?
Mode-S A6DBF3 has broadcast 3 distinct callsigns, including DAL694, DAL515, DAL459.