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
- 108
- Distinct callsigns
- 20
- Country
- US
- Last broadcast
- 43m 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 | 9 | 2026-05-08 |
| UAL862 | United Airlines | 7 | 2026-05-09 |
| UAL189 | United Airlines | 7 | 2026-05-22 |
| UAL190 | United Airlines | 6 | 2026-05-23 |
| UAL1175 | United Airlines | 6 | 2026-05-23 |
| UAL869 | United Airlines | 5 | 2026-04-15 |
| UAL809 | United Airlines | 4 | 2026-05-10 |
| UAL201 | United Airlines | 4 | 2026-05-24 |
| UAL951 | United Airlines | 3 | 2026-05-29 |
| UAL950 | United Airlines | 3 | 2026-05-28 |
| UAL878 | United Airlines | 3 | 2026-04-16 |
| UAL810 | United Airlines | 3 | 2026-05-11 |
| UAL200 | United Airlines | 3 | 2026-05-25 |
| UAL1844 | United Airlines | 3 | 2026-04-26 |
| UAL990 | United Airlines | 2 | 2026-05-16 |
| UAL989 | United Airlines | 2 | 2026-05-29 |
| UAL988 | United Airlines | 2 | 2026-05-28 |
| UAL984 | United Airlines | 2 | 2026-05-16 |
| UAL900 | United Airlines | 2 | 2026-05-15 |
| UAL857 | United Airlines | 2 | 2026-04-18 |
Recent flights last 50
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-05-29 | UAL989 | IAD → FRA | May 29, 22:55 UTC | May 30, 04:45 UTC | 5h 50m |
| 2026-05-29 | UAL951 | BRU → IAD | May 29, 10:10 UTC | May 29, 17:40 UTC | 7h 30m |
| 2026-05-28 | UAL950 | IAD → BRU | May 28, 22:35 UTC | May 29, 05:35 UTC | 7h 0m |
| 2026-05-28 | UAL988 | FRA → IAD | May 28, 10:50 UTC | May 28, 12:30 UTC | 1h 40m |
| 2026-05-28 | UAL988 | FRA → IAD | May 28, 10:49 UTC | May 28, 18:44 UTC | 7h 55m |
| 2026-05-28 | UAL42 | OGG → EWR | May 28, 00:30 UTC | May 28, 07:35 UTC | 7h 5m |
| 2026-05-28 | UAL42 | OGG → EWR | May 28, 00:30 UTC | May 28, 07:37 UTC | 7h 7m |
| 2026-05-27 | UAL435 | KOA → SFO | May 27, 15:50 UTC | May 27, 20:35 UTC | 4h 45m |
| 2026-05-27 | UAL435 | KOA → SFO | May 27, 15:39 UTC | May 27, 20:33 UTC | 4h 54m |
| 2026-05-27 | UAL3907 | HKG → GUM | May 27, 07:35 UTC | May 27, 12:20 UTC | 4h 45m |
| 2026-05-25 | UAL200 | GUM → HNL | May 25, 03:30 UTC | May 25, 03:55 UTC | 25m |
| 2026-05-24 | UAL201 | HNL → GUM | May 24, 00:44 UTC | May 24, 08:03 UTC | 7h 19m |
| 2026-05-23 | UAL1175 | SFO → HNL | May 23, 16:45 UTC | May 23, 21:20 UTC | 4h 36m |
| 2026-05-23 | UAL190 | IAH → MIA | May 23, 01:15 UTC | May 23, 13:30 UTC | 12h 14m |
| 2026-05-23 | UAL190 | IAH → MIA | May 23, 01:01 UTC | May 23, 13:29 UTC | 12h 28m |
| 2026-05-22 | UAL189 | CLE → PHX | May 22, 08:25 UTC | May 22, 21:25 UTC | 13h 0m |
| 2026-05-22 | UAL189 | CLE → PHX | May 22, 08:34 UTC | May 22, 21:25 UTC | 12h 51m |
| 2026-05-21 | UAL8244 | TPA → MCO | May 21, 22:40 UTC | May 22, 04:15 UTC | 5h 35m |
| 2026-05-21 | UAL3021 | HNL → SFO | May 21, 17:10 UTC | May 21, 18:40 UTC | 1h 30m |
| 2026-05-20 | UAL2480 | BOS → SFO | May 20, 23:15 UTC | May 21, 03:35 UTC | 4h 20m |
| 2026-05-20 | UAL872 | TPE → SFO | May 20, 02:00 UTC | May 20, 13:10 UTC | 11h 11m |
| 2026-05-18 | UAL871 | SFO → TPE | May 18, 21:40 UTC | May 19, 10:25 UTC | 12h 45m |
| 2026-05-18 | UAL190 | IAH → MIA | May 18, 01:01 UTC | May 18, 12:46 UTC | 11h 45m |
| 2026-05-18 | UAL190 | IAH → MIA | May 18, 00:55 UTC | May 18, 01:20 UTC | 25m |
| 2026-05-17 | UAL189 | CLE → PHX | May 17, 22:05 UTC | May 17, 22:15 UTC | 10m |
| 2026-05-17 | UAL189 | CLE → PHX | May 17, 08:10 UTC | May 17, 18:40 UTC | 10h 30m |
| 2026-05-17 | UAL189 | CLE → PHX | May 17, 07:44 UTC | May 17, 21:48 UTC | 14h 4m |
| 2026-05-16 | UAL984 | CDG → SFO | May 16, 14:01 UTC | May 17, 00:10 UTC | 10h 9m |
| 2026-05-16 | UAL984 | CDG → SFO | May 16, 14:14 UTC | May 16, 23:57 UTC | 9h 43m |
| 2026-05-16 | UAL990 | SFO → CDG | May 16, 01:00 UTC | May 16, 11:11 UTC | 10h 11m |
| 2026-05-15 | UAL900 | LHR → SFO | May 15, 10:50 UTC | May 15, 11:55 UTC | 1h 5m |
| 2026-05-15 | UAL900 | LHR → SFO | May 15, 10:50 UTC | May 15, 20:53 UTC | 10h 3m |
| 2026-05-14 | UAL901 | SFO → LHR | May 14, 20:40 UTC | May 15, 06:05 UTC | 9h 25m |
| 2026-05-11 | UAL810 | PHL → DEN | May 11, 14:05 UTC | May 11, 17:30 UTC | 3h 26m |
| 2026-05-11 | UAL810 | PHL → DEN | May 11, 13:41 UTC | May 12, 01:40 UTC | 11h 59m |
| 2026-05-10 | UAL809 | SEA → IAD | May 10, 21:00 UTC | May 11, 10:35 UTC | 13h 35m |
| 2026-05-10 | UAL809 | SEA → IAD | May 10, 20:57 UTC | May 11, 10:33 UTC | 13h 36m |
| 2026-05-10 | UAL34 | KIX → SFO | May 10, 08:15 UTC | May 10, 17:40 UTC | 9h 25m |
| 2026-05-10 | UAL34 | KIX → SFO | May 10, 08:05 UTC | May 10, 09:10 UTC | 1h 5m |
| 2026-05-09 | UAL35 | SFO → KIX | May 9, 18:30 UTC | May 10, 05:45 UTC | 11h 15m |
| 2026-05-09 | UAL862 | HKG → SFO | May 9, 04:11 UTC | May 9, 15:39 UTC | 11h 28m |
| 2026-05-09 | UAL862 | HKG → SFO | May 9, 04:05 UTC | May 9, 15:35 UTC | 11h 30m |
| 2026-05-08 | UAL877 | SFO → HKG | May 8, 07:04 UTC | May 8, 21:05 UTC | 14h 0m |
| 2026-05-07 | UAL810 | PHL → DEN | May 7, 14:35 UTC | May 8, 02:59 UTC | 12h 25m |
| 2026-05-06 | UAL809 | SEA → IAD | May 6, 21:12 UTC | May 7, 11:25 UTC | 14h 13m |
| 2026-05-06 | UAL809 | SEA → IAD | May 6, 21:30 UTC | May 6, 22:05 UTC | 35m |
| 2026-05-06 | UAL838 | NRT → SFO | May 6, 08:31 UTC | May 6, 16:50 UTC | 8h 19m |
| 2026-05-06 | UAL838 | NRT → SFO | May 6, 08:10 UTC | May 6, 16:45 UTC | 8h 35m |
| 2026-05-05 | UAL837 | SFO → NRT | May 5, 19:15 UTC | May 6, 05:45 UTC | 10h 30m |
| 2026-05-04 | UAL1411 | SFO → EWR | May 4, 11:45 UTC | May 4, 12:20 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 N2645U page for operator, model, and routing details .