sensors Mode-S transponder
A98ACE
ICAO 24-bit transponder address · allocated to United States
- Hex
- A98ACE
- Octal
- 52305316
- Decimal
- 11,111,118
- Country
- US
- Flights observed
- 16
- Distinct callsigns
- 1
- Country
- US
- Last broadcast
- 6h ago
Last known position
Country allocation
The ICAO 24-bit address A98ACE falls within the block assigned to United States (US) by ICAO Annex 10, Volume III. Every aircraft registered in United States receives a permanent address from this block at the time of registration; the address stays with the airframe even if the aircraft is re-registered to a different operator within the country.
Callsign history 1 distinct
| Callsign | Airline | Flights | Last seen |
|---|---|---|---|
| UNIDENT | - | 16 | 2026-07-14 |
Recent flights last 16
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-07-14 | UNIDENT | - | Jul 14, 03:50 UTC | Jul 14, 04:20 UTC | 30m |
| 2026-07-06 | UNIDENT | - | Jul 6, 01:35 UTC | Jul 6, 19:55 UTC | 18h 20m |
| 2026-07-06 | UNIDENT | - | Jul 6, 00:55 UTC | Jul 6, 19:55 UTC | 19h 0m |
| 2026-07-01 | UNIDENT | - | Jul 1, 19:25 UTC | Jul 2, 00:10 UTC | 4h 45m |
| 2026-06-21 | UNIDENT | - | Jun 21, 19:50 UTC | Jun 21, 20:54 UTC | 1h 5m |
| 2026-06-18 | UNIDENT | - | Jun 18, 19:05 UTC | Jun 19, 12:29 UTC | 17h 24m |
| 2026-06-11 | UNIDENT | - | Jun 11, 19:40 UTC | Jun 12, 03:40 UTC | 8h 0m |
| 2026-06-09 | UNIDENT | - | Jun 9, 17:35 UTC | Jun 9, 19:30 UTC | 1h 55m |
| 2026-06-04 | UNIDENT | - | Jun 4, 01:00 UTC | Jun 4, 16:40 UTC | 15h 40m |
| 2026-05-30 | UNIDENT | - | May 30, 23:15 UTC | May 30, 23:50 UTC | 35m |
| 2026-05-30 | UNIDENT | - | May 30, 06:30 UTC | May 30, 17:00 UTC | 10h 30m |
| 2026-05-28 | UNIDENT | - | May 28, 17:55 UTC | May 29, 02:40 UTC | 8h 45m |
| 2026-05-27 | UNIDENT | - | May 27, 05:09 UTC | May 27, 06:20 UTC | 1h 10m |
| 2026-05-25 | UNIDENT | - | May 25, 12:50 UTC | May 25, 18:50 UTC | 6h 0m |
| 2026-05-25 | UNIDENT | - | May 25, 03:30 UTC | May 25, 04:25 UTC | 55m |
| 2026-05-23 | UNIDENT | - | May 23, 07:15 UTC | May 23, 19:05 UTC | 11h 50m |
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.