Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

ADFF4B

ICAO 24-bit transponder address

Currently assigned to 66-4365 · Northrop T-38C Talon

Hex
ADFF4B
Octal
53377513
Decimal
11,403,083
Tail
66-4365
Type
T38
No current signal · last broadcast 1d ago
Flights observed
2
Distinct callsigns
2
Country
-
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S ADFF4B.

Callsign history 2 distinct

Callsign Airline Flights Last seen
COBRA08 - 1 2026-04-13
BREW81 - 1 2026-04-13

Recent flights last 2

DateFlightRouteTakeoffLandingDuration
2026-04-13 COBRA08 RND → RND Apr 13, 17:10 UTCApr 13, 18:10 UTC1h 0m
2026-04-13 BREW81 - Apr 13, 15:05 UTCApr 13, 15:55 UTC50m

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 66-4365 page for operator, model, and routing details .

Mode-S ADFF4B frequently asked

What is Mode-S code ADFF4B?
ADFF4B is an ICAO 24-bit transponder address. Assigned to 66-4365.
Is ADFF4B 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 ADFF4B, octal 53377513, decimal 11,403,083.
What flights does ADFF4B operate?
Mode-S ADFF4B has broadcast 2 distinct callsigns, including COBRA08, BREW81.