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 12h ago
Flights observed
9
Distinct callsigns
3
Country
US
Last broadcast
12h 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 3 distinct

Callsign Airline Flights Last seen
DAL165 Delta Air Lines 4 2026-04-13
DAL162 - 4 2026-04-13
DAL10 Delta Air Lines 1 2026-04-14

Recent flights last 9

DateFlightRouteTakeoffLandingDuration
2026-04-14 DAL10 MSP → LHR Apr 14, 10:15 UTCApr 14, 11:05 UTC50m
2026-04-13 DAL165 AMS → MSP Apr 13, 21:25 UTCApr 13, 22:25 UTC1h 0m
2026-04-13 DAL165 AMS → MSP Apr 13, 16:15 UTCApr 13, 16:25 UTC10m
2026-04-13 DAL165 AMS → MSP Apr 13, 16:10 UTCApr 13, 16:25 UTC15m
2026-04-13 DAL165 AMS → MSP Apr 13, 13:43 UTCApr 13, 22:21 UTC8h 38m
2026-04-13 DAL162 - Apr 13, 08:20 UTCApr 13, 09:00 UTC40m
2026-04-13 DAL162 - Apr 13, 07:55 UTCApr 13, 09:00 UTC1h 5m
2026-04-13 DAL162 - Apr 13, 07:30 UTCApr 13, 08:15 UTC45m
2026-04-13 DAL162 - Apr 13, 01:35 UTCApr 13, 02:20 UTC45m

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 12h 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 3 distinct callsigns, including DAL165, DAL162, DAL10.