sensors Mode-S transponder

A4B827

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N403DX · AIRBUS A-330-900 · operated by DELTA AIR LINES INC

Hex
A4B827
Octal
51134047
Decimal
10,795,047
Country
US
Tail
N403DX
Type
A339
Broadcasting now · callsign DAL10 · 16,450 ft
Flights observed
13
Distinct callsigns
5
Country
US
Last broadcast
17h ago

Current position

A4B827 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A4B827 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 5 distinct

Callsign Airline Flights Last seen
DAL224 - 4 2026-04-13
DAL221 - 4 2026-04-13
DAL56 Delta Air Lines 3 2026-04-14
DAL241 - 1 2026-04-12
DAL163 - 1 2026-04-14

Recent flights last 13

DateFlightRouteTakeoffLandingDuration
2026-04-14 DAL163 - Apr 14, 10:55 UTCApr 14, 11:05 UTC10m
2026-04-14 DAL56 SLC → AMS Apr 14, 07:10 UTCApr 14, 07:20 UTC10m
2026-04-14 DAL56 SLC → AMS Apr 14, 06:00 UTCApr 14, 07:10 UTC1h 10m
2026-04-13 DAL56 SLC → AMS Apr 13, 22:35 UTCApr 13, 23:40 UTC1h 5m
2026-04-13 DAL221 - Apr 13, 16:40 UTCApr 13, 19:00 UTC2h 20m
2026-04-13 DAL221 - Apr 13, 14:55 UTCApr 13, 15:25 UTC30m
2026-04-13 DAL221 - Apr 13, 08:50 UTCApr 13, 18:57 UTC10h 7m
2026-04-13 DAL221 - Apr 13, 08:46 UTCApr 13, 19:00 UTC10h 14m
2026-04-13 DAL224 - Apr 13, 04:20 UTCApr 13, 05:40 UTC1h 20m
2026-04-13 DAL224 - Apr 13, 04:00 UTCApr 13, 05:40 UTC1h 40m
2026-04-13 DAL224 - Apr 13, 00:20 UTCApr 13, 04:15 UTC3h 55m
2026-04-12 DAL224 - Apr 12, 23:55 UTCApr 13, 00:45 UTC50m
2026-04-12 DAL241 - Apr 12, 19:10 UTCApr 12, 20:15 UTC1h 5m

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 N403DX page for operator, model, and routing details .

Mode-S A4B827 frequently asked

What is Mode-S code A4B827?
A4B827 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N403DX.
Where is Mode-S A4B827 registered?
Mode-S code A4B827 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 A4B827 broadcasting right now?
Yes. Mode-S A4B827 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A4B827, octal 51134047, decimal 10,795,047.
What flights does A4B827 operate?
Mode-S A4B827 has broadcast 5 distinct callsigns, including DAL224, DAL221, DAL56, DAL241, DAL163.