sensors Mode-S transponder
A31A7B
ICAO 24-bit transponder address · allocated to United States
Currently assigned to N29989 · BOEING 787-9 Dreamliner · operated by UNITED AIRLINES INC
- Hex
- A31A7B
- Octal
- 50615173
- Decimal
- 10,689,147
- Country
- US
- Tail
- N29989
- Type
- B789
- Flights observed
- 202
- Distinct callsigns
- 20
- Country
- US
- Last broadcast
- 10d ago
Last known position
Country allocation
The ICAO 24-bit address A31A7B 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 | - | 13 | 2026-06-22 |
| UAL820 | - | 10 | 2026-06-22 |
| UAL2222 | United Airlines | 7 | 2026-06-06 |
| UAL1122 | United Airlines | 7 | 2026-06-06 |
| UAL839 | - | 6 | 2026-06-28 |
| UAL713 | - | 6 | 2026-06-16 |
| UAL61 | - | 6 | 2026-06-16 |
| UAL181 | United Airlines | 6 | 2026-05-23 |
| UAL842 | - | 5 | 2026-06-28 |
| UAL761 | United Airlines | 5 | 2026-05-28 |
| UAL60 | - | 5 | 2026-06-15 |
| UAL6 | United Airlines | 5 | 2026-05-30 |
| UAL262 | United Airlines | 5 | 2026-05-27 |
| UAL143 | United Airlines | 5 | 2026-05-29 |
| UAL760 | United Airlines | 4 | 2026-05-28 |
| UAL62 | United Airlines | 4 | 2026-05-31 |
| UAL3940 | - | 4 | 2026-07-03 |
| UAL27 | United Airlines | 4 | 2026-05-23 |
| UAL263 | United Airlines | 4 | 2026-05-27 |
| UAL1849 | United Airlines | 4 | 2026-04-13 |
Recent flights last 50
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-07-03 | UAL3940 | ORD → GIG | Jul 3, 11:33 UTC | Jul 3, 20:52 UTC | 9h 19m |
| 2026-07-03 | UAL3940 | - | Jul 3, 11:10 UTC | Jul 3, 20:50 UTC | 9h 40m |
| 2026-07-02 | UAL908 | AMS → ORD | Jul 2, 16:15 UTC | Jul 3, 00:25 UTC | 8h 10m |
| 2026-07-02 | UAL908 | AMS → ORD | Jul 2, 15:50 UTC | Jul 3, 00:10 UTC | 8h 20m |
| 2026-07-02 | UAL909 | ORD → AMS | Jul 2, 05:45 UTC | Jul 2, 12:45 UTC | 7h 0m |
| 2026-07-01 | UAL3940 | ORD → GIG | Jul 1, 05:29 UTC | Jul 1, 07:20 UTC | 1h 51m |
| 2026-07-01 | UAL3940 | - | Jul 1, 05:10 UTC | Jul 1, 07:20 UTC | 2h 10m |
| 2026-06-30 | UAL2096 | LAX → EWR | Jun 30, 15:40 UTC | Jun 30, 20:05 UTC | 4h 25m |
| 2026-06-30 | UAL2096 | LAX → EWR | Jun 30, 15:41 UTC | Jun 30, 20:10 UTC | 4h 29m |
| 2026-06-28 | UAL842 | - | Jun 28, 23:54 UTC | Jun 29, 12:49 UTC | 12h 55m |
| 2026-06-28 | UAL839 | - | Jun 28, 06:40 UTC | Jun 28, 07:05 UTC | 25m |
| 2026-06-28 | UAL839 | LAX → SYD | Jun 28, 06:09 UTC | Jun 28, 21:03 UTC | 14h 54m |
| 2026-06-27 | UAL935 | - | Jun 27, 12:39 UTC | Jun 27, 23:04 UTC | 10h 25m |
| 2026-06-27 | UAL923 | - | Jun 27, 09:15 UTC | Jun 27, 09:34 UTC | 20m |
| 2026-06-26 | UAL923 | - | Jun 26, 23:09 UTC | Jun 27, 02:20 UTC | 3h 10m |
| 2026-06-26 | UAL923 | LAX → LHR | Jun 26, 22:53 UTC | Jun 27, 08:58 UTC | 10h 5m |
| 2026-06-26 | UAL153 | HKG → LAX | Jun 26, 05:19 UTC | Jun 26, 18:04 UTC | 12h 45m |
| 2026-06-25 | UAL152 | LAX → HKG | Jun 25, 15:20 UTC | Jun 25, 15:34 UTC | 15m |
| 2026-06-25 | UAL152 | LAX → HKG | Jun 25, 12:10 UTC | Jun 25, 12:25 UTC | 15m |
| 2026-06-24 | UAL152 | LAX → HKG | Jun 24, 22:25 UTC | Jun 25, 11:39 UTC | 13h 15m |
| 2026-06-23 | UAL842 | SYD → LAX | Jun 23, 23:51 UTC | Jun 24, 12:49 UTC | 12h 58m |
| 2026-06-23 | UAL842 | - | Jun 23, 23:59 UTC | Jun 24, 00:55 UTC | 55m |
| 2026-06-23 | UAL839 | - | Jun 23, 06:34 UTC | Jun 23, 06:59 UTC | 25m |
| 2026-06-23 | UAL839 | LAX → SYD | Jun 23, 06:24 UTC | Jun 23, 21:11 UTC | 14h 47m |
| 2026-06-22 | UAL821 | - | Jun 22, 15:05 UTC | Jun 23, 02:45 UTC | 11h 40m |
| 2026-06-22 | UAL821 | - | Jun 22, 14:19 UTC | Jun 22, 14:34 UTC | 15m |
| 2026-06-22 | UAL821 | - | Jun 22, 11:24 UTC | Jun 22, 11:44 UTC | 20m |
| 2026-06-22 | UAL821 | - | Jun 22, 09:14 UTC | Jun 22, 09:40 UTC | 25m |
| 2026-06-22 | UAL821 | BKK → HKG | Jun 22, 09:05 UTC | Jun 22, 11:40 UTC | 2h 35m |
| 2026-06-22 | UAL820 | - | Jun 22, 02:25 UTC | Jun 22, 03:05 UTC | 40m |
| 2026-06-22 | UAL820 | - | Jun 22, 00:44 UTC | Jun 22, 01:00 UTC | 15m |
| 2026-06-22 | UAL820 | LAX → HKG | Jun 22, 00:21 UTC | Jun 22, 02:57 UTC | 2h 36m |
| 2026-06-21 | UAL820 | - | Jun 21, 07:59 UTC | Jun 21, 22:40 UTC | 14h 40m |
| 2026-06-20 | UAL821 | - | Jun 20, 14:50 UTC | Jun 21, 02:45 UTC | 11h 55m |
| 2026-06-20 | UAL821 | - | Jun 20, 13:59 UTC | Jun 20, 14:14 UTC | 15m |
| 2026-06-20 | UAL821 | - | Jun 20, 11:20 UTC | Jun 20, 11:34 UTC | 15m |
| 2026-06-20 | UAL821 | - | Jun 20, 09:09 UTC | Jun 20, 09:39 UTC | 30m |
| 2026-06-20 | UAL820 | - | Jun 20, 01:05 UTC | Jun 20, 02:19 UTC | 1h 15m |
| 2026-06-20 | UAL820 | - | Jun 20, 00:14 UTC | Jun 20, 00:24 UTC | 10m |
| 2026-06-19 | UAL820 | - | Jun 19, 07:29 UTC | Jun 19, 22:09 UTC | 14h 40m |
| 2026-06-18 | UAL353 | - | Jun 18, 23:30 UTC | Jun 19, 04:39 UTC | 5h 9m |
| 2026-06-17 | UAL83 | DEL → EWR | Jun 17, 18:25 UTC | Jun 17, 18:45 UTC | 20m |
| 2026-06-17 | UAL83 | DEL → EWR | Jun 17, 18:32 UTC | Jun 18, 09:50 UTC | 15h 18m |
| 2026-06-17 | UAL82 | EWR → DEL | Jun 17, 01:44 UTC | Jun 17, 15:50 UTC | 14h 6m |
| 2026-06-17 | UAL82 | - | Jun 17, 01:50 UTC | Jun 17, 12:10 UTC | 10h 20m |
| 2026-06-16 | UAL713 | SFO → EWR | Jun 16, 17:30 UTC | Jun 16, 22:35 UTC | 5h 6m |
| 2026-06-16 | UAL61 | MEL → SFO | Jun 16, 01:19 UTC | Jun 16, 14:36 UTC | 13h 17m |
| 2026-06-16 | UAL61 | - | Jun 16, 01:19 UTC | Jun 16, 14:35 UTC | 13h 15m |
| 2026-06-15 | UAL60 | - | Jun 15, 07:29 UTC | Jun 15, 22:45 UTC | 15h 15m |
| 2026-06-14 | UAL892 | ICN → SFO | Jun 14, 08:10 UTC | Jun 14, 18:05 UTC | 9h 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 N29989 page for operator, model, and routing details .