sensors Mode-S transponder

A6E720

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N544DN · AIRBUS A-321neo · operated by DELTA AIR LINES INC

Hex
A6E720
Octal
51563440
Decimal
10,938,144
Country
US
Tail
N544DN
Type
A21N
No current signal · last broadcast 1d ago
Flights observed
7
Distinct callsigns
4
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S A6E720.

Country allocation

The ICAO 24-bit address A6E720 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 4 distinct

Callsign Airline Flights Last seen
DAL863 - 3 2026-04-13
DAL1087 - 2 2026-04-13
DAL428 Delta Air Lines 1 2026-04-13
DAL1966 - 1 2026-04-12

Recent flights last 7

DateFlightRouteTakeoffLandingDuration
2026-04-13 DAL428 SJC → ATL Apr 13, 22:50 UTCApr 13, 23:40 UTC50m
2026-04-13 DAL1087 SLC → LAX Apr 13, 14:07 UTCApr 13, 15:31 UTC1h 24m
2026-04-13 DAL1087 SLC → LAX Apr 13, 14:02 UTCApr 13, 15:35 UTC1h 33m
2026-04-13 DAL863 - Apr 13, 03:55 UTCApr 13, 04:20 UTC25m
2026-04-13 DAL863 - Apr 13, 00:20 UTCApr 13, 04:15 UTC3h 55m
2026-04-12 DAL863 - Apr 12, 23:55 UTCApr 13, 03:50 UTC3h 55m
2026-04-12 DAL1966 - Apr 12, 17:27 UTCApr 12, 21:05 UTC3h 38m

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 N544DN page for operator, model, and routing details .

Mode-S A6E720 frequently asked

What is Mode-S code A6E720?
A6E720 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N544DN.
Where is Mode-S A6E720 registered?
Mode-S code A6E720 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 A6E720 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 A6E720, octal 51563440, decimal 10,938,144.
What flights does A6E720 operate?
Mode-S A6E720 has broadcast 4 distinct callsigns, including DAL863, DAL1087, DAL428, DAL1966.