sensors Mode-S transponder
AE636F
ICAO 24-bit transponder address
Currently assigned to 18-21031 · SIKORSKY UH-60 Black Hawk
- Hex
- AE636F
- Octal
- 53461557
- Decimal
- 11,428,719
- Tail
- 18-21031
- Type
- H60
- Flights observed
- 9
- Distinct callsigns
- 1
- Country
- -
- Last broadcast
- 14d ago
Last known position
Callsign history 1 distinct
| Callsign | Airline | Flights | Last seen |
|---|---|---|---|
| 21031 | - | 9 | 2026-06-30 |
Recent flights last 9
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-06-30 | 21031 | - | Jun 30, 15:05 UTC | Jun 30, 15:25 UTC | 20m |
| 2026-06-24 | 21031 | - | Jun 24, 14:09 UTC | Jun 24, 14:34 UTC | 25m |
| 2026-06-15 | 21031 | - | Jun 15, 17:40 UTC | Jun 15, 17:50 UTC | 10m |
| 2026-05-28 | 21031 | - | May 28, 18:50 UTC | May 28, 19:05 UTC | 15m |
| 2026-05-22 | 21031 | - | May 22, 18:15 UTC | May 22, 18:35 UTC | 20m |
| 2026-05-22 | 21031 | - | May 22, 14:55 UTC | May 22, 15:15 UTC | 20m |
| 2026-05-21 | 21031 | NEL → NEL | May 21, 15:10 UTC | May 21, 15:30 UTC | 20m |
| 2026-05-19 | 21031 | - | May 19, 14:55 UTC | May 19, 15:10 UTC | 15m |
| 2026-05-12 | 21031 | NEL → NEL | May 12, 20:20 UTC | May 12, 20:35 UTC | 15m |
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 18-21031 page for operator, model, and routing details .