sensors Mode-S transponder
A1BBF5
ICAO 24-bit transponder address · allocated to United States
Currently assigned to N21002 · CESSNA T182 Turbo Skylane · operated by GR AIRCRAFT LLC
- Hex
- A1BBF5
- Octal
- 50335765
- Decimal
- 10,599,413
- Country
- US
- Tail
- N21002
- Type
- C82S
- Flights observed
- 25
- Distinct callsigns
- 12
- Country
- US
- Last broadcast
- Jul 23, 08:50 UTC
Last known position
Country allocation
The ICAO 24-bit address A1BBF5 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 12 distinct
| Callsign | Airline | Flights | Last seen |
|---|---|---|---|
| PALAZ05 | - | 6 | 2026-07-17 |
| PALAZ10 | - | 4 | 2026-06-17 |
| N21002 | - | 4 | 2026-05-21 |
| ONCU31 | - | 2 | 2026-06-16 |
| PALAZ44 | - | 1 | 2026-06-11 |
| PALAZ34 | - | 1 | 2026-07-10 |
| PALAZ25 | - | 1 | 2026-05-13 |
| PALAZ07 | - | 1 | 2026-07-23 |
| PALAZ06 | - | 1 | 2026-07-14 |
| PALAZ03 | - | 1 | 2026-06-19 |
| PALAZ01 | - | 1 | 2026-07-20 |
| ONCU34 | - | 1 | 2026-06-15 |
Recent flights last 25
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-07-23 | PALAZ07 | - | Jul 23, 08:30 UTC | Jul 23, 08:50 UTC | 20m |
| 2026-07-20 | PALAZ01 | - | Jul 20, 07:55 UTC | Jul 20, 08:40 UTC | 45m |
| 2026-07-17 | PALAZ05 | - | Jul 17, 04:29 UTC | Jul 17, 04:54 UTC | 25m |
| 2026-07-14 | PALAZ06 | - | Jul 14, 08:40 UTC | Jul 14, 09:10 UTC | 30m |
| 2026-07-14 | PALAZ05 | - | Jul 14, 04:35 UTC | Jul 14, 04:55 UTC | 20m |
| 2026-07-13 | PALAZ05 | - | Jul 13, 08:05 UTC | Jul 13, 08:40 UTC | 35m |
| 2026-07-10 | PALAZ34 | - | Jul 10, 08:35 UTC | Jul 10, 08:50 UTC | 15m |
| 2026-06-19 | PALAZ03 | - | Jun 19, 06:44 UTC | Jun 19, 07:09 UTC | 25m |
| 2026-06-17 | PALAZ05 | - | Jun 17, 10:15 UTC | Jun 17, 10:50 UTC | 35m |
| 2026-06-17 | PALAZ10 | - | Jun 17, 06:40 UTC | Jun 17, 06:55 UTC | 15m |
| 2026-06-16 | PALAZ10 | - | Jun 16, 10:15 UTC | Jun 16, 11:00 UTC | 45m |
| 2026-06-16 | ONCU31 | - | Jun 16, 06:30 UTC | Jun 16, 07:15 UTC | 45m |
| 2026-06-15 | ONCU34 | - | Jun 15, 06:49 UTC | Jun 15, 07:10 UTC | 20m |
| 2026-06-11 | PALAZ44 | - | Jun 11, 10:05 UTC | Jun 11, 10:50 UTC | 45m |
| 2026-06-11 | - | - | Jun 11, 06:40 UTC | Jun 11, 06:50 UTC | 10m |
| 2026-06-10 | PALAZ05 | - | Jun 10, 07:00 UTC | Jun 10, 07:15 UTC | 15m |
| 2026-06-08 | PALAZ10 | - | Jun 8, 06:40 UTC | Jun 8, 07:20 UTC | 40m |
| 2026-06-03 | ONCU31 | - | Jun 3, 10:10 UTC | Jun 3, 11:10 UTC | 1h 0m |
| 2026-06-01 | PALAZ10 | - | Jun 1, 10:10 UTC | Jun 1, 10:45 UTC | 35m |
| 2026-05-21 | N21002 | - | May 21, 16:25 UTC | May 21, 17:15 UTC | 50m |
| 2026-05-21 | N21002 | - | May 21, 15:15 UTC | May 21, 16:01 UTC | 45m |
| 2026-05-20 | N21002 | - | May 20, 20:20 UTC | May 20, 21:05 UTC | 45m |
| 2026-05-20 | N21002 | - | May 20, 18:45 UTC | May 20, 19:45 UTC | 1h 0m |
| 2026-05-13 | PALAZ25 | - | May 13, 09:50 UTC | May 13, 10:55 UTC | 1h 5m |
| 2026-05-13 | PALAZ05 | - | May 13, 06:50 UTC | May 13, 07:25 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 N21002 page for operator, model, and routing details .