sensors Mode-S transponder
A09FC4
ICAO 24-bit transponder address · allocated to United States
Currently assigned to N13954 · BOEING 787-9 Dreamliner · operated by UNITED AIRLINES INC
- Hex
- A09FC4
- Octal
- 50117704
- Decimal
- 10,526,660
- Country
- US
- Tail
- N13954
- Type
- B789
- Flights observed
- 220
- Distinct callsigns
- 20
- Country
- US
- Last broadcast
- Jul 26, 22:00 UTC
Last known position
Country allocation
The ICAO 24-bit address A09FC4 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 |
|---|---|---|---|
| UAL821 | United Airlines | 13 | 2026-07-21 |
| UAL820 | United Airlines | 11 | 2026-07-20 |
| UAL805 | - | 9 | 2026-07-05 |
| UAL806 | - | 8 | 2026-07-06 |
| UAL79 | United Airlines | 8 | 2026-05-03 |
| UAL199 | - | 7 | 2026-07-13 |
| UAL863 | United Airlines | 6 | 2026-07-25 |
| UAL83 | United Airlines | 6 | 2026-06-28 |
| UAL7 | United Airlines | 6 | 2026-07-17 |
| UAL198 | - | 6 | 2026-07-12 |
| UAL187 | United Airlines | 6 | 2026-06-04 |
| UAL1855 | United Airlines | 6 | 2026-07-23 |
| UAL1849 | United Airlines | 6 | 2026-06-24 |
| UAL63 | United Airlines | 5 | 2026-07-17 |
| UAL33 | United Airlines | 5 | 2026-07-18 |
| UAL2023 | - | 5 | 2026-06-19 |
| UAL1011 | - | 5 | 2026-06-19 |
| UAL923 | United Airlines | 4 | 2026-07-18 |
| UAL842 | United Airlines | 4 | 2026-07-26 |
| UAL82 | - | 4 | 2026-06-28 |
Recent flights last 50
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-07-26 | UAL2096 | LAX → EWR | Jul 26, 17:15 UTC | Jul 26, 21:50 UTC | 4h 35m |
| 2026-07-26 | UAL842 | SYD → LAX | Jul 26, 00:15 UTC | Jul 26, 13:40 UTC | 13h 26m |
| 2026-07-25 | UAL863 | SFO → SYD | Jul 25, 07:11 UTC | Jul 25, 21:04 UTC | 13h 53m |
| 2026-07-25 | UAL863 | SFO → SYD | Jul 25, 07:05 UTC | Jul 25, 07:45 UTC | 40m |
| 2026-07-24 | UAL1227 | PHX → IAD | Jul 24, 17:45 UTC | Jul 24, 23:10 UTC | 5h 25m |
| 2026-07-23 | UAL1855 | ORD → BOS | Jul 23, 21:05 UTC | Jul 24, 01:55 UTC | 4h 50m |
| 2026-07-23 | UAL772 | DEN → DFW | Jul 23, 05:25 UTC | Jul 23, 16:30 UTC | 11h 5m |
| 2026-07-22 | UAL771 | BNA → ORD | Jul 22, 11:15 UTC | Jul 22, 21:05 UTC | 9h 50m |
| 2026-07-21 | UAL821 | SFO → MEX | Jul 21, 14:20 UTC | Jul 22, 03:25 UTC | 13h 5m |
| 2026-07-21 | UAL821 | SFO → MEX | Jul 21, 10:55 UTC | Jul 21, 11:15 UTC | 20m |
| 2026-07-21 | UAL821 | SFO → MEX | Jul 21, 08:50 UTC | Jul 21, 09:15 UTC | 25m |
| 2026-07-20 | UAL820 | MEX → SFO | Jul 20, 23:50 UTC | Jul 21, 02:05 UTC | 2h 15m |
| 2026-07-20 | UAL820 | MEX → SFO | Jul 20, 07:15 UTC | Jul 20, 20:50 UTC | 13h 35m |
| 2026-07-19 | UAL935 | - | Jul 19, 12:40 UTC | Jul 19, 22:50 UTC | 10h 10m |
| 2026-07-18 | UAL923 | LAX → LHR | Jul 18, 23:05 UTC | Jul 19, 08:55 UTC | 9h 50m |
| 2026-07-18 | UAL923 | LAX → LHR | Jul 18, 22:53 UTC | Jul 19, 08:48 UTC | 9h 55m |
| 2026-07-18 | UAL33 | NRT → LAX | Jul 18, 08:05 UTC | Jul 18, 18:00 UTC | 9h 55m |
| 2026-07-17 | UAL7 | IAH → NRT | Jul 17, 15:55 UTC | Jul 18, 04:15 UTC | 12h 21m |
| 2026-07-17 | UAL63 | GRU → IAH | Jul 17, 01:00 UTC | Jul 17, 10:25 UTC | 9h 25m |
| 2026-07-16 | UAL62 | - | Jul 16, 00:15 UTC | Jul 16, 09:20 UTC | 9h 5m |
| 2026-07-16 | UAL62 | IAH → GRU | Jul 16, 00:13 UTC | Jul 16, 09:17 UTC | 9h 4m |
| 2026-07-15 | UAL6 | - | Jul 15, 08:30 UTC | Jul 15, 20:10 UTC | 11h 40m |
| 2026-07-14 | UAL32 | - | Jul 14, 18:10 UTC | Jul 14, 19:15 UTC | 1h 5m |
| 2026-07-14 | UAL32 | LAX → NRT | Jul 14, 18:15 UTC | Jul 15, 04:32 UTC | 10h 17m |
| 2026-07-13 | UAL199 | - | Jul 13, 13:10 UTC | Jul 13, 14:50 UTC | 1h 40m |
| 2026-07-13 | UAL199 | - | Jul 13, 06:40 UTC | Jul 14, 00:10 UTC | 17h 30m |
| 2026-07-13 | UAL199 | - | Jul 13, 01:05 UTC | Jul 14, 00:10 UTC | 23h 5m |
| 2026-07-12 | UAL198 | - | Jul 12, 23:35 UTC | Jul 13, 23:00 UTC | 23h 25m |
| 2026-07-12 | UAL198 | - | Jul 12, 20:50 UTC | Jul 13, 07:01 UTC | 10h 10m |
| 2026-07-12 | UAL198 | LAX → PVG | Jul 12, 20:31 UTC | Jul 13, 09:23 UTC | 12h 52m |
| 2026-07-11 | UAL842 | SYD → LAX | Jul 11, 23:51 UTC | Jul 12, 12:42 UTC | 12h 51m |
| 2026-07-11 | UAL842 | - | Jul 11, 23:40 UTC | Jul 12, 12:35 UTC | 12h 55m |
| 2026-07-11 | UAL863 | SFO → SYD | Jul 11, 06:39 UTC | Jul 11, 21:01 UTC | 14h 22m |
| 2026-07-11 | UAL863 | SFO → SYD | Jul 11, 06:50 UTC | Jul 11, 21:05 UTC | 14h 15m |
| 2026-07-10 | UAL969 | AMS → SFO | Jul 10, 13:16 UTC | Jul 10, 23:44 UTC | 10h 28m |
| 2026-07-10 | UAL969 | - | Jul 10, 13:15 UTC | Jul 10, 23:45 UTC | 10h 30m |
| 2026-07-09 | UAL968 | SFO → AMS | Jul 9, 23:10 UTC | Jul 10, 09:00 UTC | 9h 50m |
| 2026-07-09 | UAL892 | - | Jul 9, 08:15 UTC | Jul 9, 18:35 UTC | 10h 20m |
| 2026-07-08 | UAL893 | SFO → ICN | Jul 8, 18:30 UTC | Jul 9, 06:05 UTC | 11h 35m |
| 2026-07-07 | UAL28 | - | Jul 7, 14:30 UTC | Jul 8, 03:45 UTC | 13h 15m |
| 2026-07-07 | UAL28 | - | Jul 7, 12:55 UTC | Jul 7, 13:05 UTC | 10m |
| 2026-07-07 | UAL28 | SIN → SFO | Jul 7, 13:06 UTC | Jul 8, 03:40 UTC | 14h 34m |
| 2026-07-07 | UAL29 | - | Jul 7, 10:15 UTC | Jul 7, 10:35 UTC | 20m |
| 2026-07-06 | UAL29 | - | Jul 6, 19:00 UTC | Jul 7, 08:10 UTC | 13h 10m |
| 2026-07-06 | UAL806 | - | Jul 6, 02:50 UTC | Jul 6, 12:45 UTC | 9h 55m |
| 2026-07-05 | UAL805 | SFO → ICN | Jul 5, 07:25 UTC | Jul 5, 18:55 UTC | 11h 30m |
| 2026-07-04 | UAL949 | - | Jul 4, 12:45 UTC | Jul 4, 13:00 UTC | 15m |
| 2026-07-04 | UAL949 | LHR → SFO | Jul 4, 12:25 UTC | Jul 4, 23:03 UTC | 10h 38m |
| 2026-07-03 | UAL923 | - | Jul 3, 23:10 UTC | Jul 4, 02:20 UTC | 3h 10m |
| 2026-07-03 | UAL923 | LAX → LHR | Jul 3, 23:08 UTC | Jul 4, 08:41 UTC | 9h 33m |
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 N13954 page for operator, model, and routing details .