sensors Mode-S transponder

A4CA66

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N408AN · AIRBUS A-321neo · operated by WILMINGTON TRUST CO TRUSTEE

Hex
A4CA66
Octal
51145146
Decimal
10,799,718
Country
US
Tail
N408AN
Type
A21N
No current signal · last broadcast 1d ago
Flights observed
7
Distinct callsigns
6
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S A4CA66.

Country allocation

The ICAO 24-bit address A4CA66 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 6 distinct

Callsign Airline Flights Last seen
AAL1967 - 2 2026-04-13
AAL617 - 1 2026-04-12
AAL3227 - 1 2026-04-12
AAL2937 - 1 2026-04-13
AAL2577 - 1 2026-04-13
AAL1730 American Airlines 1 2026-04-13

Recent flights last 7

DateFlightRouteTakeoffLandingDuration
2026-04-13 AAL2577 - Apr 13, 20:26 UTCApr 13, 21:46 UTC1h 20m
2026-04-13 AAL1730 LAS → PHL Apr 13, 17:15 UTCApr 13, 18:45 UTC1h 30m
2026-04-13 AAL2937 - Apr 13, 12:18 UTCApr 13, 14:50 UTC2h 32m
2026-04-13 AAL1967 - Apr 13, 00:20 UTCApr 13, 03:10 UTC2h 50m
2026-04-12 AAL1967 - Apr 12, 23:55 UTCApr 13, 03:10 UTC3h 15m
2026-04-12 AAL3227 - Apr 12, 19:10 UTCApr 12, 21:21 UTC2h 11m
2026-04-12 AAL617 - Apr 12, 17:15 UTCApr 12, 17:20 UTC5m

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 N408AN page for operator, model, and routing details .

Mode-S A4CA66 frequently asked

What is Mode-S code A4CA66?
A4CA66 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N408AN.
Where is Mode-S A4CA66 registered?
Mode-S code A4CA66 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 A4CA66 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 A4CA66, octal 51145146, decimal 10,799,718.
What flights does A4CA66 operate?
Mode-S A4CA66 has broadcast 6 distinct callsigns, including AAL1967, AAL617, AAL3227, AAL2937, AAL2577.