sensors Mode-S transponder
ADFF77
ICAO 24-bit transponder address
Currently assigned to 66-8356 · NORTHROP T-38 Talon
- Hex
- ADFF77
- Octal
- 53377567
- Decimal
- 11,403,127
- Tail
- 66-8356
- Type
- T38
- Flights observed
- 6
- Distinct callsigns
- 4
- Country
- -
- Last broadcast
- Jun 17, 21:55 UTC
Last known position
Callsign history 4 distinct
Recent flights last 6
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-06-17 | FADE3 | - | Jun 17, 21:30 UTC | Jun 17, 21:55 UTC | 25m |
| 2026-06-17 | SIRE1 | - | Jun 17, 18:20 UTC | Jun 17, 18:50 UTC | 30m |
| 2026-06-12 | KNIGHT1 | - | Jun 12, 15:20 UTC | Jun 12, 15:35 UTC | 15m |
| 2026-05-07 | LEXUS3 | - | May 7, 15:10 UTC | May 7, 16:05 UTC | 55m |
| 2026-05-05 | LEXUS3 | - | May 5, 19:45 UTC | May 5, 20:35 UTC | 50m |
| 2026-05-04 | LEXUS3 | - | May 4, 18:40 UTC | May 4, 19:15 UTC | 35m |
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 66-8356 page for operator, model, and routing details .