sensors Mode-S transponder
A2B8DB
ICAO 24-bit transponder address · allocated to United States
Currently assigned to N2748U · BOEING 777-300ER · operated by UNITED AIRLINES INC
- Hex
- A2B8DB
- Octal
- 50534333
- Decimal
- 10,664,155
- Country
- US
- Tail
- N2748U
- Type
- B77W
- Flights observed
- 222
- Distinct callsigns
- 20
- Country
- US
- Last broadcast
- 3h ago
Last known position
Country allocation
The ICAO 24-bit address A2B8DB 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 | - | 16 | 2026-07-08 |
| UAL950 | - | 13 | 2026-07-12 |
| UAL951 | - | 12 | 2026-07-13 |
| UAL878 | - | 11 | 2026-07-01 |
| UAL857 | United Airlines | 10 | 2026-05-29 |
| UAL42 | - | 10 | 2026-07-11 |
| UAL190 | - | 10 | 2026-07-08 |
| UAL869 | - | 9 | 2026-07-01 |
| UAL43 | - | 9 | 2026-07-14 |
| UAL200 | - | 9 | 2026-07-10 |
| UAL201 | - | 8 | 2026-07-09 |
| UAL862 | United Airlines | 7 | 2026-05-25 |
| UAL189 | - | 7 | 2026-07-07 |
| UAL989 | - | 6 | 2026-07-13 |
| UAL988 | - | 6 | 2026-07-11 |
| UAL872 | - | 6 | 2026-06-22 |
| UAL871 | - | 6 | 2026-06-21 |
| UAL79 | - | 6 | 2026-06-28 |
| UAL858 | United Airlines | 5 | 2026-05-31 |
| UAL838 | United Airlines | 5 | 2026-06-09 |
Recent flights last 50
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-07-14 | UAL43 | - | Jul 14, 09:40 UTC | Jul 14, 11:30 UTC | 1h 50m |
| 2026-07-13 | UAL989 | IAD → FRA | Jul 13, 21:45 UTC | Jul 14, 04:55 UTC | 7h 10m |
| 2026-07-13 | UAL951 | BRU → IAD | Jul 13, 10:45 UTC | Jul 13, 18:10 UTC | 7h 25m |
| 2026-07-12 | UAL950 | - | Jul 12, 23:30 UTC | Jul 13, 02:01 UTC | 2h 30m |
| 2026-07-12 | UAL950 | IAD → BRU | Jul 12, 23:08 UTC | Jul 13, 06:48 UTC | 7h 40m |
| 2026-07-12 | UAL951 | BRU → IAD | Jul 12, 10:25 UTC | Jul 12, 18:01 UTC | 7h 35m |
| 2026-07-11 | UAL950 | - | Jul 11, 23:20 UTC | Jul 12, 01:05 UTC | 1h 45m |
| 2026-07-11 | UAL950 | IAD → BRU | Jul 11, 23:18 UTC | Jul 12, 06:07 UTC | 6h 49m |
| 2026-07-11 | UAL988 | - | Jul 11, 11:40 UTC | Jul 11, 19:40 UTC | 8h 0m |
| 2026-07-11 | UAL42 | - | Jul 11, 00:10 UTC | Jul 11, 06:55 UTC | 6h 45m |
| 2026-07-10 | UAL435 | SFO → EWR | Jul 10, 15:39 UTC | Jul 10, 20:45 UTC | 5h 6m |
| 2026-07-10 | UAL435 | - | Jul 10, 15:35 UTC | Jul 10, 20:45 UTC | 5h 10m |
| 2026-07-10 | UAL1346 | - | Jul 10, 12:10 UTC | Jul 10, 12:45 UTC | 35m |
| 2026-07-10 | UAL200 | - | Jul 10, 03:40 UTC | Jul 10, 04:05 UTC | 25m |
| 2026-07-09 | UAL200 | GUM → HNL | Jul 9, 21:18 UTC | Jul 10, 04:01 UTC | 6h 43m |
| 2026-07-09 | UAL201 | - | Jul 9, 01:30 UTC | Jul 9, 01:55 UTC | 25m |
| 2026-07-08 | UAL1175 | - | Jul 8, 21:15 UTC | Jul 8, 21:30 UTC | 15m |
| 2026-07-08 | UAL1175 | - | Jul 8, 16:45 UTC | Jul 8, 17:20 UTC | 35m |
| 2026-07-08 | UAL190 | - | Jul 8, 01:00 UTC | Jul 8, 13:15 UTC | 12h 15m |
| 2026-07-07 | UAL189 | SFO → MNL | Jul 7, 08:30 UTC | Jul 7, 22:00 UTC | 13h 30m |
| 2026-07-06 | UAL810 | - | Jul 6, 13:45 UTC | Jul 7, 01:45 UTC | 12h 0m |
| 2026-07-05 | UAL809 | SFO → MNL | Jul 5, 21:30 UTC | Jul 6, 10:55 UTC | 13h 25m |
| 2026-07-05 | UAL1346 | - | Jul 5, 12:15 UTC | Jul 5, 12:50 UTC | 35m |
| 2026-07-05 | UAL1346 | HNL → SFO | Jul 5, 08:29 UTC | Jul 5, 12:42 UTC | 4h 13m |
| 2026-07-05 | UAL200 | - | Jul 5, 04:40 UTC | Jul 5, 05:00 UTC | 20m |
| 2026-07-04 | UAL200 | GUM → HNL | Jul 4, 22:08 UTC | Jul 5, 05:06 UTC | 6h 58m |
| 2026-07-04 | UAL201 | - | Jul 4, 01:05 UTC | Jul 4, 01:25 UTC | 20m |
| 2026-07-04 | UAL201 | HNL → GUM | Jul 4, 00:54 UTC | Jul 4, 08:26 UTC | 7h 32m |
| 2026-07-03 | UAL1175 | - | Jul 3, 21:10 UTC | Jul 3, 21:25 UTC | 15m |
| 2026-07-03 | UAL1175 | - | Jul 3, 16:40 UTC | Jul 3, 17:10 UTC | 30m |
| 2026-07-03 | UAL190 | MNL → SFO | Jul 3, 01:01 UTC | Jul 3, 12:50 UTC | 11h 49m |
| 2026-07-03 | UAL190 | - | Jul 3, 01:00 UTC | Jul 3, 12:45 UTC | 11h 45m |
| 2026-07-03 | UAL190 | MNL → SFO | Jul 3, 01:01 UTC | Jul 3, 12:43 UTC | 11h 42m |
| 2026-07-02 | UAL189 | - | Jul 2, 08:15 UTC | Jul 2, 08:40 UTC | 25m |
| 2026-07-02 | UAL189 | SFO → MNL | Jul 2, 08:19 UTC | Jul 2, 20:59 UTC | 12h 40m |
| 2026-07-01 | UAL878 | - | Jul 1, 15:15 UTC | Jul 2, 03:00 UTC | 11h 45m |
| 2026-07-01 | UAL869 | - | Jul 1, 10:40 UTC | Jul 1, 11:00 UTC | 20m |
| 2026-06-30 | UAL869 | - | Jun 30, 21:35 UTC | Jul 1, 10:05 UTC | 12h 30m |
| 2026-06-30 | UAL1960 | - | Jun 30, 11:20 UTC | Jun 30, 16:35 UTC | 5h 15m |
| 2026-06-29 | UAL78 | NRT → EWR | Jun 29, 12:05 UTC | Jun 30, 00:00 UTC | 11h 55m |
| 2026-06-28 | UAL79 | EWR → NRT | Jun 28, 20:52 UTC | Jun 29, 09:43 UTC | 12h 51m |
| 2026-06-28 | UAL79 | - | Jun 28, 20:50 UTC | Jun 29, 03:34 UTC | 6h 45m |
| 2026-06-28 | UAL43 | FRA → EWR | Jun 28, 10:10 UTC | Jun 28, 17:55 UTC | 7h 45m |
| 2026-06-27 | UAL989 | IAD → FRA | Jun 27, 21:43 UTC | Jun 28, 05:02 UTC | 7h 19m |
| 2026-06-27 | UAL989 | - | Jun 27, 21:55 UTC | Jun 27, 23:39 UTC | 1h 45m |
| 2026-06-27 | UAL951 | BRU → IAD | Jun 27, 11:00 UTC | Jun 27, 12:34 UTC | 1h 35m |
| 2026-06-27 | UAL951 | BRU → IAD | Jun 27, 10:44 UTC | Jun 27, 18:40 UTC | 7h 56m |
| 2026-06-27 | UAL950 | - | Jun 27, 04:00 UTC | Jun 27, 05:35 UTC | 1h 35m |
| 2026-06-26 | UAL950 | - | Jun 26, 22:44 UTC | Jun 27, 00:29 UTC | 1h 45m |
| 2026-06-26 | UAL951 | BRU → IAD | Jun 26, 10:35 UTC | Jun 26, 18:29 UTC | 7h 55m |
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 N2748U page for operator, model, and routing details .