sensors Mode-S transponder

A4FC00

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N420DX · AIRBUS A-330-900 · operated by DELTA AIR LINES INC

Hex
A4FC00
Octal
51176000
Decimal
10,812,416
Country
US
Tail
N420DX
Type
A339
No current signal · last broadcast 16h ago
Flights observed
13
Distinct callsigns
5
Country
US
Last broadcast
16h ago

Last known position

Most recent position reported by Mode-S A4FC00.

Country allocation

The ICAO 24-bit address A4FC00 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
DAL220 Delta Air Lines 4 2026-04-13
DAL225 - 3 2026-04-13
DAL207 Delta Air Lines 3 2026-04-14
DAL57 Delta Air Lines 2 2026-04-12
DAL112 Delta Air Lines 1 2026-04-13

Recent flights last 13

DateFlightRouteTakeoffLandingDuration
2026-04-14 DAL207 FCO → DTW Apr 14, 09:10 UTCApr 14, 10:25 UTC1h 15m
2026-04-14 DAL207 FCO → DTW Apr 14, 07:15 UTCApr 14, 17:05 UTC9h 50m
2026-04-14 DAL207 FCO → DTW Apr 14, 07:00 UTCApr 14, 16:50 UTC9h 50m
2026-04-13 DAL112 BOS → FCO Apr 13, 21:10 UTCApr 13, 22:30 UTC1h 20m
2026-04-13 DAL225 - Apr 13, 16:20 UTCApr 13, 17:45 UTC1h 25m
2026-04-13 DAL225 - Apr 13, 11:55 UTCApr 13, 12:15 UTC20m
2026-04-13 DAL225 - Apr 13, 10:25 UTCApr 13, 12:15 UTC1h 50m
2026-04-13 DAL220 SLC → CDG Apr 13, 07:55 UTCApr 13, 08:05 UTC10m
2026-04-13 DAL220 SLC → CDG Apr 13, 06:20 UTCApr 13, 08:05 UTC1h 45m
2026-04-13 DAL220 SLC → CDG Apr 13, 00:25 UTCApr 13, 01:10 UTC45m
2026-04-12 DAL220 SLC → CDG Apr 12, 23:55 UTCApr 13, 01:10 UTC1h 15m
2026-04-12 DAL57 AMS → SLC Apr 12, 18:25 UTCApr 12, 18:50 UTC25m
2026-04-12 DAL57 AMS → SLC Apr 12, 17:15 UTCApr 12, 17:35 UTC20m

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 N420DX page for operator, model, and routing details .

Mode-S A4FC00 frequently asked

What is Mode-S code A4FC00?
A4FC00 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N420DX.
Where is Mode-S A4FC00 registered?
Mode-S code A4FC00 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 A4FC00 broadcasting right now?
No active broadcast right now. Last signal was 16h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A4FC00, octal 51176000, decimal 10,812,416.
What flights does A4FC00 operate?
Mode-S A4FC00 has broadcast 5 distinct callsigns, including DAL220, DAL225, DAL207, DAL57, DAL112.