sensors Mode-S transponder

A19981

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N202AR · operated by AIRGAS

Hex
A19981
Octal
50314601
Decimal
10,590,593
Country
US
Tail
N202AR
No current signal · last broadcast 2d ago
Flights observed
7
Distinct callsigns
1
Country
US
Last broadcast
2d ago

Last known position

Most recent position reported by Mode-S A19981.

Country allocation

The ICAO 24-bit address A19981 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
N202AR - 7 2026-04-16

Recent flights last 7

DateFlightRouteTakeoffLandingDuration
2026-04-16 N202AR - Apr 16, 16:05 UTCApr 16, 17:10 UTC1h 5m
2026-04-16 N202AR - Apr 16, 12:19 UTCApr 16, 13:05 UTC45m
2026-04-15 N202AR - Apr 15, 19:05 UTCApr 15, 19:55 UTC50m
2026-04-15 N202AR - Apr 15, 17:10 UTCApr 15, 19:00 UTC1h 50m
2026-04-15 N202AR - Apr 15, 15:05 UTCApr 15, 16:25 UTC1h 20m
2026-04-15 N202AR - Apr 15, 13:01 UTCApr 15, 14:55 UTC1h 54m
2026-04-15 N202AR - Apr 15, 12:30 UTCApr 15, 12:55 UTC25m

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 N202AR page for operator, model, and routing details .

Mode-S A19981 frequently asked

What is Mode-S code A19981?
A19981 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N202AR.
Where is Mode-S A19981 registered?
Mode-S code A19981 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 A19981 broadcasting right now?
No active broadcast right now. Last signal was 2d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A19981, octal 50314601, decimal 10,590,593.
What flights does A19981 operate?
Mode-S A19981 has broadcast 1 distinct callsign, including N202AR.