sensors Mode-S transponder
AA931D
ICAO 24-bit transponder address · allocated to United States
Currently assigned to N78013 · BOEING 777-200 · operated by UNITED AIRLINES INC
- Hex
- AA931D
- Octal
- 52511435
- Decimal
- 11,178,781
- Country
- US
- Tail
- N78013
- Type
- B772
- Flights observed
- 83
- Distinct callsigns
- 20
- Country
- US
- Last broadcast
- 10h ago
Current position
Country allocation
The ICAO 24-bit address AA931D 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 |
|---|---|---|---|
| UAL888 | United Airlines | 7 | 2026-05-24 |
| UAL131 | United Airlines | 7 | 2026-04-17 |
| UAL889 | United Airlines | 5 | 2026-05-25 |
| UAL876 | United Airlines | 5 | 2026-05-17 |
| UAL875 | United Airlines | 5 | 2026-05-29 |
| UAL506 | United Airlines | 5 | 2026-04-15 |
| UAL837 | United Airlines | 4 | 2026-04-18 |
| UAL195 | United Airlines | 4 | 2026-04-13 |
| UAL1726 | United Airlines | 4 | 2026-04-16 |
| UAL97 | United Airlines | 3 | 2026-05-29 |
| UAL96 | United Airlines | 3 | 2026-05-28 |
| UAL948 | United Airlines | 3 | 2026-05-26 |
| UAL673 | United Airlines | 3 | 2026-05-27 |
| UAL672 | United Airlines | 3 | 2026-05-27 |
| UAL969 | United Airlines | 2 | 2026-05-11 |
| UAL968 | United Airlines | 2 | 2026-05-10 |
| UAL949 | United Airlines | 2 | 2026-05-26 |
| UAL917 | United Airlines | 2 | 2026-05-20 |
| UAL59 | United Airlines | 2 | 2026-05-18 |
| UAL58 | United Airlines | 2 | 2026-05-17 |
Recent flights last 50
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-05-29 | UAL875 | SFO → HND | May 29, 18:30 UTC | May 29, 19:00 UTC | 30m |
| 2026-05-29 | UAL97 | BNE → SFO | May 29, 00:55 UTC | May 29, 13:40 UTC | 12h 45m |
| 2026-05-28 | UAL96 | SFO → BNE | May 28, 06:56 UTC | May 28, 20:12 UTC | 13h 16m |
| 2026-05-28 | UAL96 | SFO → BNE | May 28, 06:55 UTC | May 28, 20:20 UTC | 13h 25m |
| 2026-05-27 | UAL673 | SFO → BOS | May 27, 14:55 UTC | May 28, 02:15 UTC | 11h 20m |
| 2026-05-27 | UAL672 | EWR → ATL | May 27, 01:29 UTC | May 27, 12:36 UTC | 11h 7m |
| 2026-05-27 | UAL672 | EWR → ATL | May 27, 01:29 UTC | May 27, 04:14 UTC | 2h 45m |
| 2026-05-26 | UAL949 | LHR → SFO | May 26, 12:14 UTC | May 26, 22:50 UTC | 10h 35m |
| 2026-05-26 | UAL948 | SFO → LHR | May 26, 00:09 UTC | May 26, 10:05 UTC | 9h 56m |
| 2026-05-26 | UAL948 | SFO → LHR | May 26, 00:19 UTC | May 26, 03:00 UTC | 2h 40m |
| 2026-05-25 | UAL889 | PEK → SFO | May 25, 11:00 UTC | May 25, 20:59 UTC | 9h 59m |
| 2026-05-24 | UAL888 | SFO → PEK | May 24, 18:15 UTC | May 25, 07:46 UTC | 13h 31m |
| 2026-05-24 | UAL888 | SFO → PEK | May 24, 18:25 UTC | May 24, 18:50 UTC | 25m |
| 2026-05-23 | UAL949 | LHR → SFO | May 23, 12:15 UTC | May 23, 22:40 UTC | 10h 26m |
| 2026-05-23 | UAL948 | SFO → LHR | May 23, 00:05 UTC | May 23, 10:00 UTC | 9h 54m |
| 2026-05-22 | UAL889 | PEK → SFO | May 22, 10:45 UTC | May 22, 12:35 UTC | 1h 50m |
| 2026-05-22 | UAL889 | PEK → SFO | May 22, 09:51 UTC | May 22, 20:37 UTC | 10h 46m |
| 2026-05-22 | UAL889 | PEK → SFO | May 22, 09:51 UTC | May 22, 20:38 UTC | 10h 47m |
| 2026-05-21 | UAL888 | SFO → PEK | May 21, 18:15 UTC | May 22, 07:38 UTC | 13h 23m |
| 2026-05-21 | UAL888 | SFO → PEK | May 21, 18:30 UTC | May 22, 06:25 UTC | 11h 55m |
| 2026-05-21 | UAL916 | AKL → SFO | May 21, 02:30 UTC | May 21, 13:45 UTC | 11h 15m |
| 2026-05-20 | UAL917 | SFO → AKL | May 20, 06:24 UTC | May 20, 19:08 UTC | 12h 44m |
| 2026-05-20 | UAL917 | SFO → AKL | May 20, 06:25 UTC | May 20, 06:50 UTC | 25m |
| 2026-05-19 | UAL673 | SFO → BOS | May 19, 14:35 UTC | May 20, 01:50 UTC | 11h 15m |
| 2026-05-19 | UAL673 | SFO → BOS | May 19, 14:31 UTC | May 20, 01:41 UTC | 11h 10m |
| 2026-05-19 | UAL672 | EWR → ATL | May 19, 01:05 UTC | May 19, 11:55 UTC | 10h 50m |
| 2026-05-18 | UAL59 | FRA → SFO | May 18, 11:10 UTC | May 18, 21:15 UTC | 10h 4m |
| 2026-05-18 | UAL59 | FRA → SFO | May 18, 11:19 UTC | May 18, 21:35 UTC | 10h 16m |
| 2026-05-17 | UAL58 | SFO → FRA | May 17, 21:07 UTC | May 18, 07:38 UTC | 10h 31m |
| 2026-05-17 | UAL58 | SFO → FRA | May 17, 21:20 UTC | May 18, 07:25 UTC | 10h 5m |
| 2026-05-17 | UAL876 | HND → SFO | May 17, 07:20 UTC | May 17, 15:55 UTC | 8h 35m |
| 2026-05-16 | UAL875 | SFO → HND | May 16, 17:55 UTC | May 17, 04:33 UTC | 10h 38m |
| 2026-05-16 | UAL875 | SFO → HND | May 16, 17:50 UTC | May 17, 04:35 UTC | 10h 45m |
| 2026-05-15 | UAL876 | HND → SFO | May 15, 17:40 UTC | May 16, 02:35 UTC | 8h 55m |
| 2026-05-14 | UAL889 | PEK → SFO | May 14, 13:45 UTC | May 14, 15:15 UTC | 1h 30m |
| 2026-05-13 | UAL888 | SFO → PEK | May 13, 21:20 UTC | May 14, 17:00 UTC | 19h 40m |
| 2026-05-13 | UAL888 | SFO → PEK | May 13, 17:50 UTC | May 14, 06:49 UTC | 12h 59m |
| 2026-05-13 | UAL888 | SFO → PEK | May 13, 17:45 UTC | May 14, 05:30 UTC | 11h 45m |
| 2026-05-13 | UAL97 | BNE → SFO | May 13, 01:00 UTC | May 13, 14:00 UTC | 13h 0m |
| 2026-05-13 | UAL97 | BNE → SFO | May 13, 00:43 UTC | May 13, 13:57 UTC | 13h 14m |
| 2026-05-12 | UAL96 | SFO → BNE | May 12, 06:50 UTC | May 12, 20:40 UTC | 13h 50m |
| 2026-05-11 | UAL969 | AMS → SFO | May 11, 13:10 UTC | May 11, 22:35 UTC | 9h 25m |
| 2026-05-10 | UAL968 | SFO → AMS | May 10, 22:15 UTC | May 11, 08:15 UTC | 10h 0m |
| 2026-05-10 | UAL3936 | DEN → SFO | May 10, 06:50 UTC | May 10, 18:55 UTC | 12h 5m |
| 2026-04-21 | UAL3935 | LHR → LAX | Apr 21, 19:10 UTC | Apr 22, 09:45 UTC | 14h 35m |
| 2026-04-21 | UAL3935 | LHR → LAX | Apr 21, 19:20 UTC | Apr 22, 08:50 UTC | 13h 30m |
| 2026-04-21 | UAL876 | HND → SFO | Apr 21, 07:15 UTC | Apr 21, 16:15 UTC | 9h 0m |
| 2026-04-20 | UAL875 | SFO → HND | Apr 20, 17:55 UTC | Apr 21, 04:27 UTC | 10h 32m |
| 2026-04-20 | UAL875 | SFO → HND | Apr 20, 17:50 UTC | Apr 21, 04:30 UTC | 10h 40m |
| 2026-04-19 | UAL969 | AMS → SFO | Apr 19, 13:15 UTC | Apr 19, 23:55 UTC | 10h 40m |
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 N78013 page for operator, model, and routing details .