sensors Mode-S transponder

A4A0D9

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N398DN · AIRBUS A-321 · operated by BANK OF UTAH TRUSTEE

Hex
A4A0D9
Octal
51120331
Decimal
10,789,081
Country
US
Tail
N398DN
Type
A321
No current signal · last broadcast 17h ago
Flights observed
12
Distinct callsigns
7
Country
US
Last broadcast
17h ago

Last known position

Most recent position reported by Mode-S A4A0D9.

Country allocation

The ICAO 24-bit address A4A0D9 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 7 distinct

Callsign Airline Flights Last seen
DAL1345 - 5 2026-04-13
DAL932 Delta Air Lines 2 2026-04-14
DAL712 - 1 2026-04-13
DAL2932 - 1 2026-04-13
DAL2696 - 1 2026-04-12
DAL1530 - 1 2026-04-13
DAL1525 Delta Air Lines 1 2026-04-12

Recent flights last 12

DateFlightRouteTakeoffLandingDuration
2026-04-14 DAL932 JFK → ATL Apr 14, 07:10 UTCApr 14, 09:05 UTC1h 55m
2026-04-14 DAL932 JFK → ATL Apr 14, 05:45 UTCApr 14, 07:10 UTC1h 25m
2026-04-13 DAL712 - Apr 13, 22:20 UTCApr 13, 23:45 UTC1h 25m
2026-04-13 DAL1345 - Apr 13, 19:50 UTCApr 13, 20:05 UTC15m
2026-04-13 DAL1345 - Apr 13, 18:40 UTCApr 13, 20:05 UTC1h 25m
2026-04-13 DAL1345 - Apr 13, 16:15 UTCApr 13, 16:50 UTC35m
2026-04-13 DAL1345 - Apr 13, 15:50 UTCApr 13, 16:50 UTC1h 0m
2026-04-13 DAL1345 - Apr 13, 15:35 UTCApr 13, 16:15 UTC40m
2026-04-13 DAL1530 - Apr 13, 12:45 UTCApr 13, 13:40 UTC55m
2026-04-13 DAL2932 - Apr 13, 02:00 UTCApr 13, 03:55 UTC1h 55m
2026-04-12 DAL2696 - Apr 12, 19:30 UTCApr 12, 20:15 UTC45m
2026-04-12 DAL1525 SNA → SEA Apr 12, 17:15 UTCApr 12, 17:45 UTC30m

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 N398DN page for operator, model, and routing details .

Mode-S A4A0D9 frequently asked

What is Mode-S code A4A0D9?
A4A0D9 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N398DN.
Where is Mode-S A4A0D9 registered?
Mode-S code A4A0D9 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 A4A0D9 broadcasting right now?
No active broadcast right now. Last signal was 17h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A4A0D9, octal 51120331, decimal 10,789,081.
What flights does A4A0D9 operate?
Mode-S A4A0D9 has broadcast 7 distinct callsigns, including DAL1345, DAL932, DAL712, DAL2932, DAL2696.