Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

AFA827

ICAO 24-bit transponder address

Currently assigned to 18-20990 · SIKORSKY UH-60 Black Hawk

Hex
AFA827
Octal
53724047
Decimal
11,511,847
Tail
18-20990
Type
H60
No current signal · last broadcast 1d ago
Flights observed
2
Distinct callsigns
1
Country
-
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S AFA827.

Callsign history 1 distinct

Callsign Airline Flights Last seen
20990 - 2 2026-04-13

Recent flights last 2

DateFlightRouteTakeoffLandingDuration
2026-04-13 20990 - Apr 13, 16:15 UTCApr 13, 16:45 UTC30m
2026-04-13 20990 - Apr 13, 15:55 UTCApr 13, 16:15 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 18-20990 page for operator, model, and routing details .

Mode-S AFA827 frequently asked

What is Mode-S code AFA827?
AFA827 is an ICAO 24-bit transponder address. Assigned to 18-20990.
Is AFA827 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 AFA827, octal 53724047, decimal 11,511,847.
What flights does AFA827 operate?
Mode-S AFA827 has broadcast 1 distinct callsign, including 20990.