sensors Mode-S transponder

A18ADA

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N199NV · operated by ALLEGIANT AIR LLC

Hex
A18ADA
Octal
50305332
Decimal
10,586,842
Country
US
Tail
N199NV
Type
A320
No current signal · last broadcast 1d ago
Flights observed
8
Distinct callsigns
6
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S A18ADA.

Country allocation

The ICAO 24-bit address A18ADA 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
AAY583 - 2 2026-04-13
AAY553 - 2 2026-04-13
AAY549 Allegiant Air 1 2026-04-12
AAY2181 - 1 2026-04-13
AAY2171 - 1 2026-04-13
AAY2168 - 1 2026-04-13

Recent flights last 8

DateFlightRouteTakeoffLandingDuration
2026-04-13 AAY2181 - Apr 13, 20:45 UTCApr 13, 23:05 UTC2h 20m
2026-04-13 AAY2168 - Apr 13, 16:50 UTCApr 13, 19:15 UTC2h 25m
2026-04-13 AAY2171 - Apr 13, 13:35 UTCApr 13, 15:45 UTC2h 10m
2026-04-13 AAY583 - Apr 13, 11:55 UTCApr 13, 12:20 UTC25m
2026-04-13 AAY583 - Apr 13, 09:55 UTCApr 13, 12:15 UTC2h 20m
2026-04-13 AAY553 - Apr 13, 03:55 UTCApr 13, 04:05 UTC10m
2026-04-13 AAY553 LAS → GRR Apr 13, 01:00 UTCApr 13, 04:05 UTC3h 5m
2026-04-12 AAY549 AZA → GRR Apr 12, 18:25 UTCApr 12, 20:15 UTC1h 50m

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 N199NV page for operator, model, and routing details .

Mode-S A18ADA frequently asked

What is Mode-S code A18ADA?
A18ADA is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N199NV.
Where is Mode-S A18ADA registered?
Mode-S code A18ADA 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 A18ADA 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 A18ADA, octal 50305332, decimal 10,586,842.
What flights does A18ADA operate?
Mode-S A18ADA has broadcast 6 distinct callsigns, including AAY583, AAY553, AAY549, AAY2181, AAY2171.