Apparatus

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sensors Mode-S transponder

ADFF4E

ICAO 24-bit transponder address

Currently assigned to 66-8399 · Northrop T-38C Talon

Hex
ADFF4E
Octal
53377516
Decimal
11,403,086
Tail
66-8399
Type
T38
No current signal · last broadcast 1d ago
Flights observed
4
Distinct callsigns
3
Country
-
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S ADFF4E.

Callsign history 3 distinct

Callsign Airline Flights Last seen
ROGUE1 - 2 2026-04-13
CARD11 - 1 2026-04-13
ANARCH4 - 1 2026-04-13

Recent flights last 4

DateFlightRouteTakeoffLandingDuration
2026-04-13 ROGUE1 - Apr 13, 19:50 UTCApr 13, 20:15 UTC25m
2026-04-13 ROGUE1 - Apr 13, 19:20 UTCApr 13, 20:10 UTC50m
2026-04-13 CARD11 - Apr 13, 16:45 UTCApr 13, 17:30 UTC45m
2026-04-13 ANARCH4 - Apr 13, 13:55 UTCApr 13, 14:45 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 66-8399 page for operator, model, and routing details .

Mode-S ADFF4E frequently asked

What is Mode-S code ADFF4E?
ADFF4E is an ICAO 24-bit transponder address. Assigned to 66-8399.
Is ADFF4E 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 ADFF4E, octal 53377516, decimal 11,403,086.
What flights does ADFF4E operate?
Mode-S ADFF4E has broadcast 3 distinct callsigns, including ROGUE1, CARD11, ANARCH4.