sensors Mode-S transponder
A31A96
ICAO 24-bit transponder address · allocated to United States
Currently assigned to N29991 · BOEING 787-9 Dreamliner · operated by UNITED AIRLINES INC
- Hex
- A31A96
- Octal
- 50615226
- Decimal
- 10,689,174
- Country
- US
- Tail
- N29991
- Type
- B789
- Flights observed
- 103
- Distinct callsigns
- 20
- Country
- US
- Last broadcast
- 4h ago
Last known position
Country allocation
The ICAO 24-bit address A31A96 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 |
|---|---|---|---|
| UAL153 | United Airlines | 12 | 2026-05-16 |
| UAL152 | United Airlines | 12 | 2026-05-15 |
| UAL29 | United Airlines | 6 | 2026-05-25 |
| UAL28 | United Airlines | 6 | 2026-05-26 |
| UAL771 | United Airlines | 5 | 2026-05-13 |
| UAL863 | United Airlines | 4 | 2026-05-18 |
| UAL772 | United Airlines | 4 | 2026-05-14 |
| UAL61 | United Airlines | 4 | 2026-05-25 |
| UAL60 | United Airlines | 4 | 2026-05-24 |
| UAL870 | United Airlines | 3 | 2026-05-19 |
| UAL713 | United Airlines | 3 | 2026-05-29 |
| UAL2692 | United Airlines | 3 | 2026-05-03 |
| UAL2222 | United Airlines | 3 | 2026-04-25 |
| UAL2 | United Airlines | 3 | 2026-04-22 |
| UAL1321 | United Airlines | 3 | 2026-05-08 |
| UAL923 | United Airlines | 2 | 2026-05-03 |
| UAL892 | United Airlines | 2 | 2026-05-23 |
| UAL842 | United Airlines | 2 | 2026-05-06 |
| UAL806 | United Airlines | 2 | 2026-05-29 |
| UAL1855 | United Airlines | 2 | 2026-05-16 |
Recent flights last 50
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-05-29 | UAL713 | ORD → DEL | May 29, 17:45 UTC | May 29, 22:31 UTC | 4h 46m |
| 2026-05-29 | UAL713 | ORD → DEL | May 29, 17:35 UTC | May 29, 22:20 UTC | 4h 45m |
| 2026-05-29 | UAL806 | ICN → SFO | May 29, 02:56 UTC | May 29, 12:32 UTC | 9h 36m |
| 2026-05-29 | UAL806 | ICN → SFO | May 29, 02:30 UTC | May 29, 12:35 UTC | 10h 5m |
| 2026-05-28 | UAL805 | SFO → ICN | May 28, 07:25 UTC | May 28, 19:10 UTC | 11h 45m |
| 2026-05-27 | UAL1757 | PIT → DEN | May 27, 23:00 UTC | May 28, 04:05 UTC | 5h 5m |
| 2026-05-27 | UAL1849 | MCO → EWR | May 27, 15:30 UTC | May 27, 20:15 UTC | 4h 45m |
| 2026-05-26 | UAL28 | SIN → SFO | May 26, 15:09 UTC | May 27, 04:39 UTC | 13h 30m |
| 2026-05-25 | UAL29 | SFO → SIN | May 25, 18:35 UTC | May 26, 10:42 UTC | 16h 7m |
| 2026-05-25 | UAL29 | SFO → SIN | May 25, 18:45 UTC | May 26, 08:15 UTC | 13h 29m |
| 2026-05-25 | UAL61 | BRU → EWR | May 25, 01:55 UTC | May 25, 03:05 UTC | 1h 10m |
| 2026-05-24 | UAL61 | BRU → EWR | May 24, 19:35 UTC | May 25, 14:50 UTC | 19h 15m |
| 2026-05-24 | UAL60 | SFO → MEL | May 24, 07:35 UTC | May 25, 03:05 UTC | 19h 30m |
| 2026-05-24 | UAL60 | SFO → MEL | May 24, 07:25 UTC | May 24, 21:50 UTC | 14h 25m |
| 2026-05-24 | UAL60 | SFO → MEL | May 24, 07:01 UTC | May 24, 22:12 UTC | 15h 11m |
| 2026-05-23 | UAL892 | ICN → SFO | May 23, 08:00 UTC | May 23, 18:10 UTC | 10h 10m |
| 2026-05-22 | UAL893 | SFO → ICN | May 22, 18:15 UTC | May 23, 06:00 UTC | 11h 44m |
| 2026-05-22 | UAL61 | BRU → EWR | May 22, 01:09 UTC | May 22, 14:32 UTC | 13h 23m |
| 2026-05-22 | UAL61 | BRU → EWR | May 22, 01:05 UTC | May 22, 02:55 UTC | 1h 50m |
| 2026-05-21 | UAL60 | SFO → MEL | May 21, 07:10 UTC | May 21, 22:10 UTC | 15h 0m |
| 2026-05-20 | UAL28 | SIN → SFO | May 20, 15:50 UTC | May 21, 03:40 UTC | 11h 50m |
| 2026-05-19 | UAL29 | SFO → SIN | May 19, 18:20 UTC | May 20, 09:10 UTC | 14h 51m |
| 2026-05-19 | UAL870 | SYD → SFO | May 19, 00:50 UTC | May 19, 13:30 UTC | 12h 40m |
| 2026-05-18 | UAL863 | SFO → SYD | May 18, 06:35 UTC | May 18, 21:00 UTC | 14h 24m |
| 2026-05-17 | UAL1227 | PHX → IAD | May 17, 17:45 UTC | May 17, 23:15 UTC | 5h 30m |
| 2026-05-16 | UAL1855 | ORD → BOS | May 16, 20:25 UTC | May 17, 01:05 UTC | 4h 40m |
| 2026-05-16 | UAL153 | HKG → LAX | May 16, 05:30 UTC | May 16, 17:25 UTC | 11h 56m |
| 2026-05-16 | UAL153 | HKG → LAX | May 16, 04:45 UTC | May 16, 05:00 UTC | 15m |
| 2026-05-16 | UAL153 | HKG → LAX | May 16, 02:05 UTC | May 16, 02:25 UTC | 20m |
| 2026-05-15 | UAL152 | LAX → HKG | May 15, 13:20 UTC | May 15, 13:40 UTC | 20m |
| 2026-05-15 | UAL152 | LAX → HKG | May 15, 12:49 UTC | May 15, 15:35 UTC | 2h 46m |
| 2026-05-15 | UAL152 | LAX → HKG | May 15, 08:50 UTC | May 15, 09:15 UTC | 25m |
| 2026-05-14 | UAL152 | LAX → HKG | May 14, 19:10 UTC | May 15, 08:15 UTC | 13h 5m |
| 2026-05-14 | UAL772 | DEN → DFW | May 14, 05:05 UTC | May 14, 05:30 UTC | 25m |
| 2026-05-14 | UAL772 | DEN → DFW | May 14, 04:29 UTC | May 14, 15:37 UTC | 11h 8m |
| 2026-05-13 | UAL772 | DEN → DFW | May 13, 17:35 UTC | May 14, 15:45 UTC | 22h 10m |
| 2026-05-13 | UAL772 | DEN → DFW | May 13, 17:05 UTC | May 14, 15:30 UTC | 22h 25m |
| 2026-05-13 | UAL771 | BNA → ORD | May 13, 11:35 UTC | May 14, 07:00 UTC | 19h 25m |
| 2026-05-13 | UAL771 | BNA → ORD | May 13, 10:55 UTC | May 14, 07:00 UTC | 20h 5m |
| 2026-05-13 | UAL771 | BNA → ORD | May 13, 07:35 UTC | May 14, 07:00 UTC | 23h 25m |
| 2026-05-13 | UAL771 | BNA → ORD | May 13, 06:55 UTC | May 13, 19:05 UTC | 12h 10m |
| 2026-05-13 | UAL771 | BNA → ORD | May 13, 06:46 UTC | May 13, 20:14 UTC | 13h 28m |
| 2026-05-12 | UAL199 | PVG → LAX | May 12, 06:10 UTC | May 12, 23:20 UTC | 17h 10m |
| 2026-05-11 | UAL198 | LAX → PVG | May 11, 20:15 UTC | May 12, 14:45 UTC | 18h 30m |
| 2026-05-11 | UAL153 | HKG → LAX | May 11, 05:08 UTC | May 11, 17:37 UTC | 12h 29m |
| 2026-05-11 | UAL153 | HKG → LAX | May 11, 04:55 UTC | May 11, 05:55 UTC | 1h 0m |
| 2026-05-11 | UAL153 | HKG → LAX | May 11, 02:15 UTC | May 11, 02:20 UTC | 5m |
| 2026-05-10 | UAL152 | LAX → HKG | May 10, 12:54 UTC | May 10, 13:10 UTC | 15m |
| 2026-05-09 | UAL152 | LAX → HKG | May 9, 19:14 UTC | May 10, 10:05 UTC | 14h 50m |
| 2026-05-08 | UAL1321 | MIA → EWR | May 8, 16:15 UTC | May 8, 21:25 UTC | 5h 10m |
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 N29991 page for operator, model, and routing details .