sensors Mode-S transponder

A4AD08

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N400EC · CESSNA 550 Citation S2 · operated by DELTA MIKE HOLDINGS LLC

Hex
A4AD08
Octal
51126410
Decimal
10,792,200
Country
US
Tail
N400EC
Type
C550
No current signal · last broadcast 1d ago
Flights observed
6
Distinct callsigns
1
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S A4AD08.

Country allocation

The ICAO 24-bit address A4AD08 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 1 distinct

Callsign Airline Flights Last seen
N400EC - 6 2026-04-13

Recent flights last 6

DateFlightRouteTakeoffLandingDuration
2026-04-13 N400EC - Apr 13, 17:55 UTCApr 13, 19:30 UTC1h 35m
2026-04-13 N400EC - Apr 13, 13:50 UTCApr 13, 14:40 UTC50m
2026-04-13 N400EC - Apr 13, 12:20 UTCApr 13, 13:10 UTC50m
2026-04-13 N400EC - Apr 13, 12:10 UTCApr 13, 13:10 UTC1h 0m
2026-04-13 N400EC - Apr 13, 00:20 UTCApr 13, 00:40 UTC20m
2026-04-12 N400EC - Apr 12, 23:55 UTCApr 13, 00:40 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 N400EC page for operator, model, and routing details .

Mode-S A4AD08 frequently asked

What is Mode-S code A4AD08?
A4AD08 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N400EC.
Where is Mode-S A4AD08 registered?
Mode-S code A4AD08 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 A4AD08 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 A4AD08, octal 51126410, decimal 10,792,200.
What flights does A4AD08 operate?
Mode-S A4AD08 has broadcast 1 distinct callsign, including N400EC.