sensors Mode-S transponder
A2B8B8
ICAO 24-bit transponder address · allocated to United States
Currently assigned to N2747U · BOEING 777-300ER · operated by UNITED AIRLINES INC
- Hex
- A2B8B8
- Octal
- 50534270
- Decimal
- 10,664,120
- Country
- US
- Tail
- N2747U
- Type
- B77W
- Flights observed
- 236
- Distinct callsigns
- 20
- Country
- US
- Last broadcast
- 9h ago
Last known position
Country allocation
The ICAO 24-bit address A2B8B8 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 |
|---|---|---|---|
| UAL1175 | - | 19 | 2026-07-01 |
| UAL857 | - | 15 | 2026-06-22 |
| UAL1960 | United Airlines | 15 | 2026-05-09 |
| UAL42 | - | 13 | 2026-07-04 |
| UAL41 | United Airlines | 11 | 2026-06-09 |
| UAL201 | - | 11 | 2026-07-02 |
| UAL200 | - | 11 | 2026-07-03 |
| UAL858 | - | 10 | 2026-06-23 |
| UAL1346 | - | 10 | 2026-07-03 |
| UAL988 | - | 9 | 2026-07-04 |
| UAL878 | - | 9 | 2026-07-13 |
| UAL869 | - | 8 | 2026-07-12 |
| UAL862 | - | 7 | 2026-06-26 |
| UAL43 | - | 7 | 2026-07-07 |
| UAL40 | United Airlines | 7 | 2026-06-08 |
| UAL2011 | United Airlines | 7 | 2026-04-17 |
| UAL989 | - | 6 | 2026-07-06 |
| UAL872 | - | 6 | 2026-06-21 |
| UAL871 | - | 6 | 2026-06-20 |
| UAL435 | - | 6 | 2026-07-03 |
Recent flights last 50
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-07-13 | UAL878 | HKG → SFO | Jul 13, 14:51 UTC | Jul 14, 03:30 UTC | 12h 39m |
| 2026-07-13 | UAL878 | - | Jul 13, 14:55 UTC | Jul 14, 03:40 UTC | 12h 45m |
| 2026-07-12 | UAL869 | SFO → HKG | Jul 12, 21:15 UTC | Jul 13, 10:20 UTC | 13h 5m |
| 2026-07-10 | UAL878 | HKG → SFO | Jul 10, 14:51 UTC | Jul 11, 03:59 UTC | 13h 8m |
| 2026-07-10 | UAL878 | - | Jul 10, 14:50 UTC | Jul 10, 15:10 UTC | 20m |
| 2026-07-09 | UAL869 | SFO → HKG | Jul 9, 21:55 UTC | Jul 10, 11:20 UTC | 13h 25m |
| 2026-07-09 | UAL190 | - | Jul 9, 01:10 UTC | Jul 9, 13:20 UTC | 12h 10m |
| 2026-07-08 | UAL189 | SFO → MNL | Jul 8, 08:30 UTC | Jul 8, 21:50 UTC | 13h 20m |
| 2026-07-07 | UAL1844 | EWR → SFO | Jul 7, 22:34 UTC | Jul 8, 04:31 UTC | 5h 57m |
| 2026-07-07 | UAL1844 | EWR → SFO | Jul 7, 22:45 UTC | Jul 8, 04:45 UTC | 6h 0m |
| 2026-07-07 | UAL43 | - | Jul 7, 09:35 UTC | Jul 7, 17:25 UTC | 7h 50m |
| 2026-07-06 | UAL989 | IAD → FRA | Jul 6, 23:45 UTC | Jul 7, 06:40 UTC | 6h 55m |
| 2026-07-05 | UAL951 | BRU → IAD | Jul 5, 11:15 UTC | Jul 5, 19:05 UTC | 7h 50m |
| 2026-07-05 | UAL950 | - | Jul 5, 01:15 UTC | Jul 5, 03:25 UTC | 2h 10m |
| 2026-07-04 | UAL950 | IAD → BRU | Jul 4, 22:43 UTC | Jul 5, 08:01 UTC | 9h 18m |
| 2026-07-04 | UAL988 | - | Jul 4, 11:10 UTC | Jul 4, 19:30 UTC | 8h 20m |
| 2026-07-04 | UAL42 | EWR → FRA | Jul 4, 00:30 UTC | Jul 4, 08:12 UTC | 7h 42m |
| 2026-07-04 | UAL42 | - | Jul 4, 01:25 UTC | Jul 4, 03:10 UTC | 1h 45m |
| 2026-07-03 | UAL435 | SFO → EWR | Jul 3, 16:05 UTC | Jul 3, 21:00 UTC | 4h 55m |
| 2026-07-03 | UAL1346 | - | Jul 3, 12:10 UTC | Jul 3, 12:50 UTC | 40m |
| 2026-07-03 | UAL1346 | - | Jul 3, 08:25 UTC | Jul 3, 08:35 UTC | 10m |
| 2026-07-03 | UAL200 | - | Jul 3, 03:45 UTC | Jul 3, 04:10 UTC | 25m |
| 2026-07-02 | UAL200 | GUM → HNL | Jul 2, 21:33 UTC | Jul 3, 04:06 UTC | 6h 33m |
| 2026-07-02 | UAL201 | - | Jul 2, 00:45 UTC | Jul 2, 00:55 UTC | 10m |
| 2026-07-01 | UAL1175 | - | Jul 1, 21:15 UTC | Jul 1, 21:35 UTC | 20m |
| 2026-07-01 | UAL1175 | - | Jul 1, 16:50 UTC | Jul 1, 17:15 UTC | 25m |
| 2026-07-01 | UAL190 | - | Jul 1, 01:00 UTC | Jul 1, 12:55 UTC | 11h 55m |
| 2026-06-30 | UAL189 | - | Jun 30, 08:40 UTC | Jun 30, 22:00 UTC | 13h 20m |
| 2026-06-30 | UAL189 | SFO → MNL | Jun 30, 08:40 UTC | Jun 30, 21:44 UTC | 13h 4m |
| 2026-06-29 | UAL878 | HKG → SFO | Jun 29, 14:51 UTC | Jun 30, 03:39 UTC | 12h 48m |
| 2026-06-29 | UAL878 | HKG → SFO | Jun 29, 14:54 UTC | Jun 30, 03:40 UTC | 12h 46m |
| 2026-06-28 | UAL869 | SFO → HKG | Jun 28, 21:04 UTC | Jun 29, 10:34 UTC | 13h 30m |
| 2026-06-27 | UAL878 | HKG → SFO | Jun 27, 15:00 UTC | Jun 28, 03:00 UTC | 12h 0m |
| 2026-06-27 | UAL869 | - | Jun 27, 11:00 UTC | Jun 27, 11:14 UTC | 15m |
| 2026-06-26 | UAL869 | - | Jun 26, 21:20 UTC | Jun 27, 10:29 UTC | 13h 10m |
| 2026-06-26 | UAL862 | - | Jun 26, 04:30 UTC | Jun 26, 17:19 UTC | 12h 50m |
| 2026-06-26 | UAL862 | HKG → SFO | Jun 26, 04:11 UTC | Jun 26, 17:00 UTC | 12h 49m |
| 2026-06-25 | UAL877 | SFO → HKG | Jun 25, 07:21 UTC | Jun 25, 20:51 UTC | 13h 30m |
| 2026-06-25 | UAL877 | SFO → HKG | Jun 25, 07:25 UTC | Jun 25, 20:49 UTC | 13h 25m |
| 2026-06-24 | UAL878 | - | Jun 24, 14:50 UTC | Jun 25, 03:29 UTC | 12h 40m |
| 2026-06-23 | UAL869 | SFO → HKG | Jun 23, 21:05 UTC | Jun 24, 10:35 UTC | 13h 30m |
| 2026-06-23 | UAL858 | PVG → SFO | Jun 23, 04:44 UTC | Jun 23, 15:05 UTC | 10h 21m |
| 2026-06-22 | UAL857 | - | Jun 22, 06:15 UTC | Jun 23, 05:59 UTC | 23h 45m |
| 2026-06-21 | UAL857 | SFO → PVG | Jun 21, 21:17 UTC | Jun 22, 08:57 UTC | 11h 40m |
| 2026-06-21 | UAL857 | - | Jun 21, 21:05 UTC | Jun 22, 08:04 UTC | 11h 0m |
| 2026-06-21 | UAL872 | - | Jun 21, 02:10 UTC | Jun 21, 13:24 UTC | 11h 15m |
| 2026-06-20 | UAL871 | - | Jun 20, 10:09 UTC | Jun 20, 10:29 UTC | 20m |
| 2026-06-19 | UAL871 | - | Jun 19, 22:30 UTC | Jun 20, 08:49 UTC | 10h 20m |
| 2026-06-19 | UAL1346 | - | Jun 19, 08:40 UTC | Jun 19, 12:59 UTC | 4h 20m |
| 2026-06-19 | UAL200 | - | Jun 19, 03:49 UTC | Jun 19, 04:10 UTC | 20m |
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 N2747U page for operator, model, and routing details .