sensors Mode-S transponder
A271BB
ICAO 24-bit transponder address · allocated to United States
Currently assigned to N257CK · CIRRUS SF-50 Vision · operated by STRAIGHT UP LEASING INC
- Hex
- A271BB
- Octal
- 50470673
- Decimal
- 10,645,947
- Country
- US
- Tail
- N257CK
- Type
- SF50
- Flights observed
- 33
- Distinct callsigns
- 1
- Country
- US
- Last broadcast
- 6h ago
Last known position
Country allocation
The ICAO 24-bit address A271BB 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 |
|---|---|---|---|
| N257CK | - | 33 | 2026-06-28 |
Recent flights last 33
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-06-28 | N257CK | HSH → RDD | Jun 28, 17:50 UTC | Jun 28, 19:49 UTC | 2h 0m |
| 2026-06-22 | N257CK | - | Jun 22, 19:54 UTC | Jun 22, 20:24 UTC | 30m |
| 2026-06-22 | N257CK | - | Jun 22, 18:30 UTC | Jun 22, 19:24 UTC | 55m |
| 2026-06-22 | N257CK | - | Jun 22, 00:14 UTC | Jun 22, 00:50 UTC | 35m |
| 2026-06-19 | N257CK | - | Jun 19, 00:10 UTC | Jun 19, 00:49 UTC | 40m |
| 2026-06-18 | N257CK | - | Jun 18, 22:10 UTC | Jun 18, 23:00 UTC | 50m |
| 2026-06-18 | N257CK | - | Jun 18, 20:15 UTC | Jun 18, 21:15 UTC | 1h 0m |
| 2026-06-17 | N257CK | MCC → RDD | Jun 17, 01:35 UTC | Jun 17, 02:10 UTC | 35m |
| 2026-06-16 | N257CK | RDD → MCC | Jun 16, 00:15 UTC | Jun 16, 00:45 UTC | 30m |
| 2026-06-12 | N257CK | HSH → RDD | Jun 12, 17:50 UTC | Jun 12, 19:40 UTC | 1h 50m |
| 2026-06-07 | N257CK | - | Jun 7, 15:15 UTC | Jun 7, 16:20 UTC | 1h 5m |
| 2026-06-05 | N257CK | - | Jun 5, 16:35 UTC | Jun 5, 18:30 UTC | 1h 55m |
| 2026-06-05 | N257CK | RDD → MCC | Jun 5, 15:15 UTC | Jun 5, 15:50 UTC | 35m |
| 2026-05-28 | N257CK | MCC → RDD | May 28, 00:15 UTC | May 28, 00:50 UTC | 35m |
| 2026-05-26 | N257CK | RDD → MCC | May 26, 21:14 UTC | May 26, 21:44 UTC | 30m |
| 2026-05-25 | N257CK | - | May 25, 21:40 UTC | May 25, 22:15 UTC | 35m |
| 2026-05-24 | N257CK | - | May 24, 17:10 UTC | May 24, 17:50 UTC | 40m |
| 2026-05-19 | N257CK | - | May 19, 17:35 UTC | May 19, 18:20 UTC | 45m |
| 2026-05-19 | N257CK | - | May 19, 16:30 UTC | May 19, 17:00 UTC | 30m |
| 2026-05-12 | N257CK | - | May 12, 18:10 UTC | May 12, 18:25 UTC | 15m |
| 2026-05-12 | N257CK | - | May 12, 16:40 UTC | May 12, 17:40 UTC | 1h 0m |
| 2026-05-10 | N257CK | - | May 10, 23:19 UTC | May 10, 23:55 UTC | 35m |
| 2026-05-08 | N257CK | - | May 8, 22:35 UTC | May 8, 23:15 UTC | 40m |
| 2026-05-07 | N257CK | MCC → RDD | May 7, 00:00 UTC | May 7, 00:35 UTC | 35m |
| 2026-05-05 | N257CK | - | May 5, 16:25 UTC | May 5, 16:55 UTC | 30m |
| 2026-05-01 | N257CK | - | May 1, 00:30 UTC | May 1, 00:45 UTC | 15m |
| 2026-04-30 | N257CK | - | Apr 30, 22:50 UTC | Apr 30, 23:00 UTC | 10m |
| 2026-04-28 | N257CK | - | Apr 28, 20:20 UTC | Apr 28, 20:55 UTC | 35m |
| 2026-04-23 | N257CK | - | Apr 23, 21:10 UTC | Apr 23, 21:45 UTC | 35m |
| 2026-04-20 | N257CK | HSH → RDD | Apr 20, 02:50 UTC | Apr 20, 04:30 UTC | 1h 40m |
| 2026-04-15 | N257CK | - | Apr 15, 18:10 UTC | Apr 15, 18:25 UTC | 15m |
| 2026-04-15 | N257CK | - | Apr 15, 17:05 UTC | Apr 15, 17:35 UTC | 30m |
| 2026-04-14 | N257CK | - | Apr 14, 18:20 UTC | Apr 14, 18:45 UTC | 25m |
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 N257CK page for operator, model, and routing details .