Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

AFEFFD

ICAO 24-bit transponder address

Currently assigned to 25-21329 · SIKORSKY UH-60 Black Hawk

Hex
AFEFFD
Octal
53767775
Decimal
11,530,237
Tail
25-21329
Type
H60
No current signal · last broadcast 13h ago
Flights observed
4
Distinct callsigns
2
Country
-
Last broadcast
13h ago

Last known position

Most recent position reported by Mode-S AFEFFD.

Callsign history 2 distinct

Callsign Airline Flights Last seen
ALAMO40 - 3 2026-07-17
R21329 - 1 2026-07-16

Recent flights last 4

DateFlightRouteTakeoffLandingDuration
2026-07-17 ALAMO40 - Jul 17, 19:05 UTCJul 17, 20:04 UTC1h 0m
2026-07-17 ALAMO40 HAR → MGW Jul 17, 16:04 UTCJul 17, 17:25 UTC1h 20m
2026-07-17 ALAMO40 - Jul 17, 13:50 UTCJul 17, 14:50 UTC1h 0m
2026-07-16 R21329 - Jul 16, 17:20 UTCJul 16, 17:35 UTC15m

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 25-21329 page for operator, model, and routing details .

Mode-S AFEFFD frequently asked

What is Mode-S code AFEFFD?
AFEFFD is an ICAO 24-bit transponder address. Assigned to 25-21329.
Is AFEFFD broadcasting right now?
No active broadcast right now. Last signal was 13h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AFEFFD, octal 53767775, decimal 11,530,237.
What flights does AFEFFD operate?
Mode-S AFEFFD has broadcast 2 distinct callsigns, including ALAMO40, R21329.