Apparatus

Try JFK, AAL1290, BAW, or N225AN.

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 Jul 26, 22:15 UTC
Flights observed
539
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 22:15 UTC

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 20 distinct

Callsign Airline Flights Last seen
DAL1659 - 11 2026-07-21
DAL999 - 8 2026-07-16
DAL2602 - 8 2026-07-16
DAL1181 - 8 2026-07-04
DAL995 Delta Air Lines 7 2026-06-10
DAL974 Delta Air Lines 7 2026-07-25
DAL765 Delta Air Lines 7 2026-07-20
DAL839 Delta Air Lines 6 2026-04-29
DAL766 - 6 2026-07-14
DAL2465 - 6 2026-07-05
DAL2121 - 6 2026-06-29
DAL1455 - 6 2026-07-14
DAL1252 Delta Air Lines 6 2026-07-21
DAL660 Delta Air Lines 5 2026-07-25
DAL402 Delta Air Lines 5 2026-05-06
DAL2858 Delta Air Lines 5 2026-07-21
DAL1573 Delta Air Lines 5 2026-07-20
DAL1530 Delta Air Lines 5 2026-06-14
DAL1345 - 5 2026-04-13
DAL957 Delta Air Lines 4 2026-07-26

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 DAL957 JFK → SFO Jul 26, 21:20 UTCJul 26, 22:15 UTC55m
2026-07-26 DAL957 JFK → SFO Jul 26, 17:10 UTCJul 26, 19:50 UTC2h 40m
2026-07-26 DAL1334 SAN → SEA Jul 26, 14:15 UTCJul 26, 15:35 UTC1h 20m
2026-07-26 DAL1334 SAN → SEA Jul 26, 11:15 UTCJul 26, 12:55 UTC1h 40m
2026-07-26 DAL912 CLT → ATL Jul 26, 06:05 UTCJul 26, 09:15 UTC3h 11m
2026-07-25 DAL660 ATL → SLC Jul 25, 23:55 UTCJul 26, 03:20 UTC3h 25m
2026-07-25 DAL974 MSP → LAX Jul 25, 19:25 UTCJul 25, 21:10 UTC1h 45m
2026-07-25 DAL2719 TLH → ATL Jul 25, 14:10 UTCJul 25, 16:20 UTC2h 10m
2026-07-25 DAL2719 TLH → ATL Jul 25, 14:08 UTCJul 25, 16:15 UTC2h 7m
2026-07-25 DAL2538 MSP → BIL Jul 25, 10:20 UTCJul 25, 12:45 UTC2h 25m
2026-07-25 DAL2938 SJC → SLC Jul 25, 03:30 UTCJul 25, 04:25 UTC55m
2026-07-24 DAL540 BOS → TPA Jul 24, 21:45 UTCJul 25, 01:50 UTC4h 5m
2026-07-24 DAL540 BOS → TPA Jul 24, 16:25 UTCJul 24, 20:10 UTC3h 45m
2026-07-24 DAL341 BOS → SEA Jul 24, 12:20 UTCJul 24, 14:45 UTC2h 25m
2026-07-24 DAL1705 PHX → JFK Jul 24, 04:20 UTCJul 24, 05:55 UTC1h 35m
2026-07-24 DAL2612 MSY → ATL Jul 24, 00:00 UTCJul 24, 01:40 UTC1h 40m
2026-07-23 DAL2612 MSY → ATL Jul 23, 20:50 UTCJul 23, 22:20 UTC1h 30m
2026-07-23 DAL2849 DCA → DTW Jul 23, 17:20 UTCJul 23, 18:50 UTC1h 30m
2026-07-23 DAL2849 DCA → DTW Jul 23, 14:30 UTCJul 23, 16:10 UTC1h 40m
2026-07-23 DAL2538 MSP → BIL Jul 23, 10:50 UTCJul 23, 13:20 UTC2h 30m
2026-07-23 DAL2932 MSP → RDU Jul 23, 02:20 UTCJul 23, 04:15 UTC1h 55m
2026-07-22 DAL2271 CVG → RSW Jul 22, 23:30 UTCJul 23, 01:00 UTC1h 30m
2026-07-22 DAL2271 CVG → RSW Jul 22, 23:28 UTCJul 23, 00:57 UTC1h 29m
2026-07-22 DAL530 ATL → BOS Jul 22, 18:10 UTCJul 22, 20:50 UTC2h 40m
2026-07-22 DAL2836 BOS → RDU Jul 22, 15:05 UTCJul 22, 16:30 UTC1h 25m
2026-07-22 DAL2836 BOS → RDU Jul 22, 11:45 UTCJul 22, 13:05 UTC1h 20m
2026-07-21 DAL1252 MSP → BOS Jul 21, 23:25 UTCJul 22, 01:00 UTC1h 35m
2026-07-21 DAL1252 MSP → BOS Jul 21, 23:24 UTCJul 22, 00:52 UTC1h 28m
2026-07-21 DAL1659 LAS → SLC Jul 21, 20:25 UTCJul 21, 21:15 UTC50m
2026-07-21 DAL1659 SLC → LAS Jul 21, 17:45 UTCJul 21, 18:40 UTC55m
2026-07-21 DAL2858 SLC → SJC Jul 21, 14:40 UTCJul 21, 16:15 UTC1h 35m
2026-07-21 DAL2016 BOS → ORD Jul 21, 03:35 UTCJul 21, 05:10 UTC1h 35m
2026-07-20 DAL765 DTW → SLC Jul 20, 22:05 UTCJul 21, 01:40 UTC3h 35m
2026-07-20 DAL765 DTW → SLC Jul 20, 22:02 UTCJul 21, 01:32 UTC3h 30m
2026-07-20 DAL308 LGA → DTW Jul 20, 19:05 UTCJul 20, 20:25 UTC1h 20m
2026-07-20 DAL1573 BOS → TPA Jul 20, 13:15 UTCJul 20, 15:15 UTC2h 0m
2026-07-20 DAL1733 ATL → MCO Jul 20, 04:17 UTCJul 20, 05:16 UTC59m
2026-07-19 DAL957 JFK → SFO Jul 19, 22:30 UTCJul 20, 01:05 UTC2h 35m
2026-07-19 DAL957 JFK → SFO Jul 19, 17:20 UTCJul 19, 20:00 UTC2h 40m
2026-07-18 DAL1036 MSP → ATL Jul 18, 22:35 UTCJul 19, 00:45 UTC2h 10m
2026-07-18 DAL1036 MSP → ATL Jul 18, 22:35 UTCJul 19, 00:41 UTC2h 6m
2026-07-18 DAL2825 ATL → MSP Jul 18, 18:45 UTCJul 18, 20:50 UTC2h 5m
2026-07-18 DAL1089 ATL → RSW Jul 18, 15:20 UTCJul 18, 16:35 UTC1h 15m
2026-07-18 DAL1089 ATL → RSW Jul 18, 12:25 UTCJul 18, 14:00 UTC1h 35m
2026-07-18 DAL912 CLT → ATL Jul 18, 05:45 UTCJul 18, 09:05 UTC3h 20m
2026-07-18 DAL912 CLT → ATL Jul 18, 05:44 UTCJul 18, 09:03 UTC3h 19m
2026-07-18 DAL833 - Jul 18, 02:35 UTCJul 18, 04:00 UTC1h 26m
2026-07-17 DAL1252 SLC → SAN Jul 17, 23:25 UTCJul 18, 00:55 UTC1h 30m
2026-07-17 DAL1659 LAS → SLC Jul 17, 20:49 UTCJul 17, 21:43 UTC54m
2026-07-17 DAL1659 LAS → SLC Jul 17, 20:50 UTCJul 17, 21:50 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 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 Jul 26, 22:15 UTC.
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 20 distinct callsigns, including DAL1659, DAL999, DAL2602, DAL1181, DAL995.