Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

A4B0BB

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N401DZ · AIRBUS A-330-900 · operated by DELTA AIR LINES INC

Hex
A4B0BB
Octal
51130273
Decimal
10,793,147
Country
US
Tail
N401DZ
Type
A339
No current signal · last broadcast 1d ago
Flights observed
147
Distinct callsigns
20
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S A4B0BB.

Country allocation

The ICAO 24-bit address A4B0BB 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
DAL257 Delta Air Lines 9 2026-05-27
DAL162 Delta Air Lines 9 2026-05-09
DAL58 Delta Air Lines 7 2026-05-28
DAL124 Delta Air Lines 7 2026-05-10
DAL56 Delta Air Lines 6 2026-05-06
DAL241 Delta Air Lines 6 2026-05-18
DAL223 Delta Air Lines 6 2026-05-21
DAL221 Delta Air Lines 6 2026-05-06
DAL137 Delta Air Lines 6 2026-04-19
DAL67 Delta Air Lines 5 2026-05-22
DAL66 Delta Air Lines 5 2026-05-21
DAL224 Delta Air Lines 5 2026-05-05
DAL222 Delta Air Lines 5 2026-05-17
DAL16 Delta Air Lines 5 2026-05-19
DAL136 Delta Air Lines 5 2026-04-20
DAL71 Delta Air Lines 4 2026-05-26
DAL48 Delta Air Lines 4 2026-04-15
DAL17 Delta Air Lines 4 2026-05-19
DAL165 Delta Air Lines 4 2026-04-13
DAL125 Delta Air Lines 4 2026-05-10

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-05-28 DAL9 LHR → ATL May 28, 11:45 UTCMay 28, 13:05 UTC1h 20m
2026-05-28 DAL9 LHR → ATL May 28, 11:40 UTCMay 28, 19:26 UTC7h 46m
2026-05-28 DAL58 BOS → LHR May 28, 00:29 UTCMay 28, 06:45 UTC6h 16m
2026-05-28 DAL58 BOS → LHR May 28, 00:30 UTCMay 28, 06:50 UTC6h 20m
2026-05-27 DAL257 AMS → BOS May 27, 13:04 UTCMay 27, 19:51 UTC6h 47m
2026-05-27 DAL257 AMS → BOS May 27, 13:05 UTCMay 27, 14:45 UTC1h 40m
2026-05-26 DAL70 ATL → AMS May 26, 20:00 UTCMay 27, 04:09 UTC8h 10m
2026-05-26 DAL71 AMS → ATL May 26, 07:59 UTCMay 26, 16:59 UTC9h 0m
2026-05-26 DAL71 AMS → ATL May 26, 07:55 UTCMay 26, 16:55 UTC9h 0m
2026-05-25 DAL70 ATL → AMS May 25, 19:56 UTCMay 26, 03:52 UTC7h 56m
2026-05-25 DAL70 ATL → AMS May 25, 19:59 UTCMay 26, 03:45 UTC7h 45m
2026-05-24 DAL297 SPN → NRT May 24, 08:45 UTCMay 24, 20:05 UTC11h 20m
2026-05-23 DAL296 HND → ATL May 23, 19:50 UTCMay 24, 06:05 UTC10h 15m
2026-05-22 DAL67 FCO → ATL May 22, 12:15 UTCMay 22, 14:45 UTC2h 30m
2026-05-22 DAL67 FCO → ATL May 22, 12:13 UTCMay 22, 22:22 UTC10h 9m
2026-05-21 DAL66 ATL → FCO May 21, 23:25 UTCMay 22, 08:20 UTC8h 55m
2026-05-21 DAL223 ATH → ATL May 21, 07:05 UTCMay 21, 18:50 UTC11h 45m
2026-05-20 DAL240 BOS → ATH May 20, 19:45 UTCMay 21, 04:10 UTC8h 25m
2026-05-20 DAL59 LHR → BOS May 20, 08:50 UTCMay 20, 15:45 UTC6h 55m
2026-05-19 DAL16 DTW → LHR May 19, 23:05 UTCMay 20, 06:00 UTC6h 56m
2026-05-19 DAL17 LHR → DTW May 19, 10:05 UTCMay 19, 17:40 UTC7h 35m
2026-05-18 DAL58 BOS → LHR May 18, 23:32 UTCMay 19, 05:36 UTC6h 4m
2026-05-18 DAL58 BOS → LHR May 18, 23:35 UTCMay 19, 05:45 UTC6h 10m
2026-05-18 DAL241 ATH → BOS May 18, 11:10 UTCMay 18, 20:45 UTC9h 34m
2026-05-17 DAL222 ATL → ATH May 17, 22:16 UTCMay 18, 08:39 UTC10h 23m
2026-05-17 DAL222 ATL → ATH May 17, 22:20 UTCMay 18, 06:45 UTC8h 25m
2026-05-17 DAL215 FCO → ATL May 17, 08:20 UTCMay 17, 18:40 UTC10h 20m
2026-05-16 DAL214 ATL → FCO May 16, 20:10 UTCMay 17, 05:10 UTC9h 0m
2026-05-15 DAL67 FCO → ATL May 15, 11:30 UTCMay 15, 21:45 UTC10h 14m
2026-05-14 DAL66 ATL → FCO May 14, 23:20 UTCMay 15, 02:15 UTC2h 55m
2026-05-14 DAL66 ATL → FCO May 14, 23:16 UTCMay 15, 08:13 UTC8h 57m
2026-05-14 DAL195 BCN → ATL May 14, 10:20 UTCMay 14, 19:45 UTC9h 25m
2026-05-13 DAL250 ICN → SEA May 13, 23:50 UTCMay 14, 06:35 UTC6h 45m
2026-05-13 DAL251 NAS → MIA May 13, 13:40 UTCMay 13, 21:05 UTC7h 25m
2026-05-13 DAL194 ATL → BCN May 13, 02:50 UTCMay 13, 11:20 UTC8h 30m
2026-05-12 DAL297 SPN → NRT May 12, 10:35 UTCMay 12, 22:20 UTC11h 45m
2026-05-11 DAL296 HND → ATL May 11, 21:50 UTCMay 12, 07:40 UTC9h 50m
2026-05-11 DAL71 AMS → ATL May 11, 07:35 UTCMay 11, 16:50 UTC9h 15m
2026-05-11 DAL71 AMS → ATL May 11, 07:31 UTCMay 11, 16:38 UTC9h 7m
2026-05-10 DAL256 BOS → AMS May 10, 21:14 UTCMay 11, 03:30 UTC6h 15m
2026-05-10 DAL125 LIS → BOS May 10, 12:30 UTCMay 10, 19:00 UTC6h 30m
2026-05-10 DAL124 BOS → LIS May 10, 03:43 UTCMay 10, 09:59 UTC6h 16m
2026-05-10 DAL124 BOS → LIS May 10, 03:45 UTCMay 10, 09:55 UTC6h 10m
2026-05-09 DAL257 AMS → BOS May 9, 13:15 UTCMay 9, 20:13 UTC6h 58m
2026-05-09 DAL257 AMS → BOS May 9, 13:15 UTCMay 9, 14:45 UTC1h 30m
2026-05-09 DAL162 MSP → AMS May 9, 01:40 UTCMay 9, 02:35 UTC55m
2026-05-09 DAL162 MSP → AMS May 9, 01:45 UTCMay 9, 09:22 UTC7h 37m
2026-05-09 DAL162 MSP → AMS May 9, 01:20 UTCMay 9, 01:25 UTC5m
2026-05-08 DAL299 JFK → SFO May 8, 13:05 UTCMay 8, 23:05 UTC10h 0m
2026-05-08 DAL299 JFK → SFO May 8, 13:02 UTCMay 8, 23:02 UTC10h 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 N401DZ page for operator, model, and routing details .

Mode-S A4B0BB frequently asked

What is Mode-S code A4B0BB?
A4B0BB is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N401DZ.
Where is Mode-S A4B0BB registered?
Mode-S code A4B0BB 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 A4B0BB 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 A4B0BB, octal 51130273, decimal 10,793,147.
What flights does A4B0BB operate?
Mode-S A4B0BB has broadcast 20 distinct callsigns, including DAL257, DAL162, DAL58, DAL124, DAL56.