sensors Mode-S transponder
A290F3
ICAO 24-bit transponder address · allocated to United States
Currently assigned to N2645U · BOEING 777-300ER · operated by UNITED AIRLINES INC
- Hex
- A290F3
- Octal
- 50510363
- Decimal
- 10,653,939
- Country
- US
- Tail
- N2645U
- Type
- B77W
- Flights observed
- 226
- Distinct callsigns
- 20
- Country
- US
- Last broadcast
- 3h ago
Current position
Country allocation
The ICAO 24-bit address A290F3 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 20 distinct
| Callsign | Airline | Flights | Last seen |
|---|---|---|---|
| UAL877 | United Airlines | 11 | 2026-06-02 |
| UAL189 | - | 11 | 2026-06-23 |
| UAL869 | - | 10 | 2026-06-21 |
| UAL190 | - | 10 | 2026-06-24 |
| UAL1175 | - | 10 | 2026-06-24 |
| UAL878 | - | 9 | 2026-06-22 |
| UAL41 | United Airlines | 9 | 2026-06-28 |
| UAL858 | - | 8 | 2026-07-13 |
| UAL857 | - | 8 | 2026-07-12 |
| UAL43 | - | 8 | 2026-06-27 |
| UAL872 | - | 7 | 2026-07-07 |
| UAL862 | United Airlines | 7 | 2026-05-09 |
| UAL40 | - | 7 | 2026-06-27 |
| UAL201 | - | 7 | 2026-06-25 |
| UAL951 | United Airlines | 6 | 2026-06-08 |
| UAL871 | - | 6 | 2026-07-05 |
| UAL200 | - | 6 | 2026-06-26 |
| UAL1844 | - | 6 | 2026-06-28 |
| UAL950 | United Airlines | 5 | 2026-06-07 |
| UAL838 | - | 5 | 2026-07-10 |
Recent flights last 50
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-07-13 | UAL837 | SFO → NRT | Jul 13, 20:10 UTC | Jul 14, 06:00 UTC | 9h 50m |
| 2026-07-13 | UAL858 | - | Jul 13, 05:31 UTC | Jul 13, 16:05 UTC | 10h 35m |
| 2026-07-13 | UAL858 | PVG → SFO | Jul 13, 04:44 UTC | Jul 13, 16:02 UTC | 11h 18m |
| 2026-07-12 | UAL858 | - | Jul 12, 10:50 UTC | Jul 13, 07:20 UTC | 20h 30m |
| 2026-07-12 | UAL858 | - | Jul 12, 09:30 UTC | Jul 13, 07:20 UTC | 21h 50m |
| 2026-07-12 | UAL857 | SFO → PVG | Jul 12, 00:12 UTC | Jul 12, 12:04 UTC | 11h 52m |
| 2026-07-12 | UAL857 | - | Jul 12, 00:20 UTC | Jul 12, 00:40 UTC | 20m |
| 2026-07-10 | UAL838 | - | Jul 10, 08:55 UTC | Jul 10, 09:25 UTC | 30m |
| 2026-07-10 | UAL838 | NRT → SFO | Jul 10, 08:36 UTC | Jul 10, 18:33 UTC | 9h 57m |
| 2026-07-09 | UAL837 | - | Jul 9, 20:10 UTC | Jul 10, 06:00 UTC | 9h 50m |
| 2026-07-09 | UAL858 | - | Jul 9, 06:10 UTC | Jul 9, 16:15 UTC | 10h 5m |
| 2026-07-09 | UAL858 | PVG → SFO | Jul 9, 05:04 UTC | Jul 9, 16:09 UTC | 11h 5m |
| 2026-07-08 | UAL857 | - | Jul 8, 06:50 UTC | Jul 9, 06:45 UTC | 23h 55m |
| 2026-07-07 | UAL857 | - | Jul 7, 21:00 UTC | Jul 8, 08:15 UTC | 11h 15m |
| 2026-07-07 | UAL872 | TPE → SFO | Jul 7, 02:23 UTC | Jul 7, 15:00 UTC | 12h 37m |
| 2026-07-07 | UAL872 | - | Jul 7, 02:25 UTC | Jul 7, 03:25 UTC | 1h 0m |
| 2026-07-05 | UAL871 | SFO → TPE | Jul 5, 22:08 UTC | Jul 6, 10:27 UTC | 12h 19m |
| 2026-07-05 | UAL871 | - | Jul 5, 22:05 UTC | Jul 6, 08:45 UTC | 10h 40m |
| 2026-07-05 | UAL872 | - | Jul 5, 04:45 UTC | Jul 5, 13:55 UTC | 9h 10m |
| 2026-07-05 | UAL872 | - | Jul 5, 02:50 UTC | Jul 5, 03:00 UTC | 10m |
| 2026-07-03 | UAL871 | SFO → TPE | Jul 3, 22:28 UTC | Jul 4, 10:34 UTC | 12h 6m |
| 2026-07-03 | UAL871 | - | Jul 3, 22:25 UTC | Jul 3, 22:45 UTC | 20m |
| 2026-07-03 | UAL858 | - | Jul 3, 05:25 UTC | Jul 3, 15:45 UTC | 10h 20m |
| 2026-07-02 | UAL857 | - | Jul 2, 06:51 UTC | Jul 3, 06:45 UTC | 23h 54m |
| 2026-07-01 | UAL857 | - | Jul 1, 20:55 UTC | Jul 2, 08:20 UTC | 11h 25m |
| 2026-07-01 | UAL1960 | - | Jul 1, 11:20 UTC | Jul 1, 16:35 UTC | 5h 15m |
| 2026-06-30 | UAL78 | NRT → EWR | Jun 30, 09:00 UTC | Jun 30, 20:55 UTC | 11h 55m |
| 2026-06-30 | UAL78 | NRT → EWR | Jun 30, 08:58 UTC | Jun 30, 20:53 UTC | 11h 55m |
| 2026-06-29 | UAL837 | SFO → NRT | Jun 29, 20:19 UTC | Jun 30, 06:30 UTC | 10h 11m |
| 2026-06-28 | UAL1844 | - | Jun 28, 22:29 UTC | Jun 29, 04:00 UTC | 5h 30m |
| 2026-06-28 | UAL41 | FCO → EWR | Jun 28, 16:49 UTC | Jun 28, 18:19 UTC | 1h 30m |
| 2026-06-28 | UAL41 | FCO → EWR | Jun 28, 09:25 UTC | Jun 28, 16:39 UTC | 7h 15m |
| 2026-06-27 | UAL40 | EWR → FCO | Jun 27, 23:00 UTC | Jun 28, 06:24 UTC | 7h 25m |
| 2026-06-27 | UAL43 | - | Jun 27, 11:39 UTC | Jun 27, 19:24 UTC | 7h 45m |
| 2026-06-27 | UAL43 | FRA → EWR | Jun 27, 11:41 UTC | Jun 27, 19:25 UTC | 7h 44m |
| 2026-06-27 | UAL42 | - | Jun 27, 00:14 UTC | Jun 27, 07:10 UTC | 6h 55m |
| 2026-06-26 | UAL435 | SFO → EWR | Jun 26, 15:49 UTC | Jun 26, 20:24 UTC | 4h 35m |
| 2026-06-26 | UAL435 | SFO → EWR | Jun 26, 15:46 UTC | Jun 26, 20:24 UTC | 4h 38m |
| 2026-06-26 | UAL1346 | - | Jun 26, 08:24 UTC | Jun 26, 13:04 UTC | 4h 40m |
| 2026-06-26 | UAL200 | - | Jun 26, 03:39 UTC | Jun 26, 04:04 UTC | 25m |
| 2026-06-25 | UAL201 | - | Jun 25, 01:40 UTC | Jun 25, 01:50 UTC | 10m |
| 2026-06-24 | UAL1175 | - | Jun 24, 21:19 UTC | Jun 24, 21:34 UTC | 15m |
| 2026-06-24 | UAL1175 | - | Jun 24, 16:54 UTC | Jun 24, 17:29 UTC | 35m |
| 2026-06-24 | UAL190 | - | Jun 24, 01:44 UTC | Jun 24, 02:05 UTC | 20m |
| 2026-06-24 | UAL190 | MNL → SFO | Jun 24, 01:31 UTC | Jun 24, 13:13 UTC | 11h 42m |
| 2026-06-24 | UAL190 | MNL → SFO | Jun 24, 01:31 UTC | Jun 24, 13:15 UTC | 11h 44m |
| 2026-06-23 | UAL189 | SFO → MNL | Jun 23, 08:39 UTC | Jun 23, 22:15 UTC | 13h 35m |
| 2026-06-22 | UAL878 | - | Jun 22, 15:40 UTC | Jun 23, 03:04 UTC | 11h 25m |
| 2026-06-22 | UAL878 | - | Jun 22, 14:55 UTC | Jun 22, 15:05 UTC | 10m |
| 2026-06-22 | UAL878 | HKG → SFO | Jun 22, 14:51 UTC | Jun 23, 03:03 UTC | 12h 12m |
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 N2645U page for operator, model, and routing details .