sensors Mode-S transponder
A31961
ICAO 24-bit transponder address · allocated to United States
Currently assigned to N29907 · BOEING 787-8 Dreamliner · operated by UNITED AIRLINES INC
- Hex
- A31961
- Octal
- 50614541
- Decimal
- 10,688,865
- Country
- US
- Tail
- N29907
- Type
- B788
- Flights observed
- 125
- Distinct callsigns
- 20
- Country
- US
- Last broadcast
- 2h ago
Last known position
Country allocation
The ICAO 24-bit address A31961 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 |
|---|---|---|---|
| UAL952 | United Airlines | 11 | 2026-06-03 |
| UAL612 | - | 10 | 2026-06-15 |
| UAL415 | United Airlines | 10 | 2026-04-28 |
| UAL953 | United Airlines | 8 | 2026-06-05 |
| UAL770 | United Airlines | 8 | 2026-05-31 |
| UAL108 | United Airlines | 8 | 2026-06-08 |
| UAL613 | United Airlines | 7 | 2026-05-25 |
| UAL996 | United Airlines | 5 | 2026-06-11 |
| UAL982 | United Airlines | 5 | 2026-06-09 |
| UAL992 | United Airlines | 4 | 2026-06-13 |
| UAL991 | - | 4 | 2026-06-14 |
| UAL983 | United Airlines | 4 | 2026-06-10 |
| UAL981 | United Airlines | 4 | 2026-06-01 |
| UAL769 | United Airlines | 4 | 2026-05-31 |
| UAL416 | United Airlines | 4 | 2026-04-28 |
| UAL109 | United Airlines | 4 | 2026-06-09 |
| UAL980 | United Airlines | 3 | 2026-06-01 |
| UAL543 | United Airlines | 3 | 2026-05-05 |
| UAL202 | United Airlines | 3 | 2026-04-25 |
| UAL997 | - | 2 | 2026-06-11 |
Recent flights last 50
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-06-15 | UAL612 | - | Jun 15, 09:54 UTC | Jun 16, 02:24 UTC | 16h 30m |
| 2026-06-15 | UAL612 | - | Jun 15, 03:19 UTC | Jun 16, 02:15 UTC | 22h 55m |
| 2026-06-14 | UAL991 | BCN → IAD | Jun 14, 09:35 UTC | Jun 14, 17:45 UTC | 8h 10m |
| 2026-06-13 | UAL992 | IAD → BCN | Jun 13, 23:00 UTC | Jun 14, 06:15 UTC | 7h 15m |
| 2026-06-13 | UAL991 | BCN → IAD | Jun 13, 10:25 UTC | Jun 13, 18:25 UTC | 8h 0m |
| 2026-06-13 | UAL991 | BCN → IAD | Jun 13, 10:17 UTC | Jun 13, 18:24 UTC | 8h 7m |
| 2026-06-13 | UAL992 | IAD → BCN | Jun 13, 01:15 UTC | Jun 13, 08:25 UTC | 7h 10m |
| 2026-06-13 | UAL992 | IAD → BCN | Jun 13, 01:05 UTC | Jun 13, 02:15 UTC | 1h 10m |
| 2026-06-11 | UAL997 | ACC → IAD | Jun 11, 22:38 UTC | Jun 12, 08:52 UTC | 10h 14m |
| 2026-06-11 | UAL996 | IAD → ACC | Jun 11, 01:20 UTC | Jun 11, 09:00 UTC | 7h 40m |
| 2026-06-10 | UAL983 | ATH → IAD | Jun 10, 10:45 UTC | Jun 10, 21:05 UTC | 10h 20m |
| 2026-06-09 | UAL982 | IAD → ATH | Jun 9, 23:15 UTC | Jun 10, 08:15 UTC | 9h 0m |
| 2026-06-09 | UAL109 | EDI → EWR | Jun 9, 10:30 UTC | Jun 9, 19:35 UTC | 9h 5m |
| 2026-06-08 | UAL108 | EWR → EDI | Jun 8, 21:53 UTC | Jun 9, 05:27 UTC | 7h 34m |
| 2026-06-08 | UAL108 | EWR → EDI | Jun 8, 21:50 UTC | Jun 9, 05:35 UTC | 7h 45m |
| 2026-06-08 | UAL997 | ACC → IAD | Jun 8, 00:15 UTC | Jun 8, 08:35 UTC | 8h 20m |
| 2026-06-07 | UAL996 | IAD → ACC | Jun 7, 07:05 UTC | Jun 8, 01:15 UTC | 18h 10m |
| 2026-06-07 | UAL996 | IAD → ACC | Jun 7, 00:19 UTC | Jun 8, 00:15 UTC | 23h 55m |
| 2026-06-07 | UAL996 | IAD → ACC | Jun 7, 00:10 UTC | Jun 7, 08:10 UTC | 8h 0m |
| 2026-06-06 | UAL996 | IAD → ACC | Jun 6, 23:26 UTC | Jun 7, 09:59 UTC | 10h 33m |
| 2026-06-06 | UAL983 | ATH → IAD | Jun 6, 09:19 UTC | Jun 6, 19:34 UTC | 10h 15m |
| 2026-06-05 | UAL982 | IAD → ATH | Jun 5, 21:45 UTC | Jun 6, 06:40 UTC | 8h 55m |
| 2026-06-05 | UAL109 | EDI → EWR | Jun 5, 10:30 UTC | Jun 5, 18:45 UTC | 8h 15m |
| 2026-06-05 | UAL953 | ORD → MUC | Jun 5, 00:05 UTC | Jun 5, 07:45 UTC | 7h 40m |
| 2026-06-03 | UAL952 | MUC → ORD | Jun 3, 09:40 UTC | Jun 3, 11:45 UTC | 2h 5m |
| 2026-06-03 | UAL952 | MUC → ORD | Jun 3, 09:47 UTC | Jun 3, 18:12 UTC | 8h 25m |
| 2026-06-03 | UAL952 | MUC → ORD | Jun 3, 09:47 UTC | Jun 3, 18:43 UTC | 8h 56m |
| 2026-06-02 | UAL108 | EWR → EDI | Jun 2, 22:25 UTC | Jun 3, 05:40 UTC | 7h 15m |
| 2026-06-02 | UAL109 | EDI → EWR | Jun 2, 10:15 UTC | Jun 2, 18:10 UTC | 7h 55m |
| 2026-06-01 | UAL953 | ORD → MUC | Jun 1, 23:42 UTC | Jun 2, 07:27 UTC | 7h 45m |
| 2026-06-01 | UAL953 | ORD → MUC | Jun 1, 23:15 UTC | Jun 2, 07:30 UTC | 8h 15m |
| 2026-06-01 | UAL981 | DUB → ORD | Jun 1, 11:00 UTC | Jun 1, 17:35 UTC | 6h 35m |
| 2026-06-01 | UAL980 | ORD → DUB | Jun 1, 01:45 UTC | Jun 1, 08:35 UTC | 6h 50m |
| 2026-05-31 | UAL770 | IAH → EWR | May 31, 13:45 UTC | May 31, 22:25 UTC | 8h 40m |
| 2026-05-31 | UAL769 | BDL → ORD | May 31, 09:00 UTC | May 31, 11:05 UTC | 2h 5m |
| 2026-05-30 | UAL770 | IAH → EWR | May 30, 22:45 UTC | May 30, 22:50 UTC | 5m |
| 2026-05-30 | UAL770 | IAH → EWR | May 30, 14:01 UTC | May 30, 22:29 UTC | 8h 28m |
| 2026-05-30 | UAL770 | IAH → EWR | May 30, 13:55 UTC | May 30, 22:50 UTC | 8h 55m |
| 2026-05-30 | UAL769 | BDL → ORD | May 30, 03:30 UTC | May 30, 11:40 UTC | 8h 10m |
| 2026-05-29 | UAL952 | MUC → ORD | May 29, 09:40 UTC | May 29, 18:20 UTC | 8h 40m |
| 2026-05-28 | UAL108 | EWR → EDI | May 28, 21:53 UTC | May 29, 05:57 UTC | 8h 4m |
| 2026-05-28 | UAL108 | EWR → EDI | May 28, 22:20 UTC | May 29, 00:15 UTC | 1h 55m |
| 2026-05-28 | UAL991 | BCN → IAD | May 28, 09:35 UTC | May 28, 17:30 UTC | 7h 55m |
| 2026-05-27 | UAL992 | IAD → BCN | May 27, 23:15 UTC | May 28, 06:20 UTC | 7h 5m |
| 2026-05-27 | UAL983 | ATH → IAD | May 27, 09:00 UTC | May 27, 19:00 UTC | 10h 0m |
| 2026-05-26 | UAL982 | IAD → ATH | May 26, 21:34 UTC | May 27, 06:55 UTC | 9h 20m |
| 2026-05-25 | UAL613 | LOS → IAD | May 25, 23:15 UTC | May 26, 10:04 UTC | 10h 49m |
| 2026-05-25 | UAL612 | IAD → LOS | May 25, 10:05 UTC | May 26, 02:24 UTC | 16h 20m |
| 2026-05-25 | UAL612 | IAD → LOS | May 25, 04:20 UTC | May 26, 02:24 UTC | 22h 4m |
| 2026-05-25 | UAL612 | IAD → LOS | May 25, 03:45 UTC | May 26, 02:15 UTC | 22h 29m |
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 N29907 page for operator, model, and routing details .