sensors Mode-S transponder
A31A54
ICAO 24-bit transponder address · allocated to United States
Currently assigned to N30PX · GULFSTREAM G280 · operated by UNITED AIRLINES INC
- Hex
- A31A54
- Octal
- 50615124
- Decimal
- 10,689,108
- Country
- US
- Tail
- N30PX
- Type
- G280
- Flights observed
- 83
- Distinct callsigns
- 20
- Country
- US
- Last broadcast
- 21d ago
Last known position
Country allocation
The ICAO 24-bit address A31A54 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 |
|---|---|---|---|
| UAL26 | United Airlines | 13 | 2026-04-23 |
| UAL27 | United Airlines | 9 | 2026-04-23 |
| UAL178 | United Airlines | 7 | 2026-04-24 |
| UAL177 | United Airlines | 7 | 2026-04-24 |
| UAL181 | United Airlines | 5 | 2026-04-21 |
| UAL263 | United Airlines | 4 | 2026-04-17 |
| UAL99 | United Airlines | 3 | 2026-05-03 |
| UAL760 | United Airlines | 3 | 2026-04-25 |
| UAL262 | United Airlines | 3 | 2026-04-17 |
| UAL199D | United Airlines | 3 | 2026-05-01 |
| UAL198 | United Airlines | 3 | 2026-04-30 |
| UAL923 | United Airlines | 2 | 2026-05-06 |
| UAL78 | United Airlines | 2 | 2026-04-27 |
| UAL761 | United Airlines | 2 | 2026-04-25 |
| UAL3894 | United Airlines | 2 | 2026-05-08 |
| UAL187 | United Airlines | 2 | 2026-04-28 |
| UAL182 | United Airlines | 2 | 2026-04-20 |
| UAL143 | United Airlines | 2 | 2026-04-26 |
| UAL142 | United Airlines | 2 | 2026-04-20 |
| UAL98 | United Airlines | 1 | 2026-05-02 |
Recent flights last 50
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-05-08 | UAL3894 | ORD → AMA | May 8, 17:00 UTC | May 9, 05:00 UTC | 12h 0m |
| 2026-05-08 | UAL3894 | ORD → AMA | May 8, 16:41 UTC | May 9, 07:18 UTC | 14h 37m |
| 2026-05-07 | UAL935 | LHR → LAX | May 7, 12:25 UTC | May 7, 22:30 UTC | 10h 5m |
| 2026-05-06 | UAL923 | LAX → LHR | May 6, 22:50 UTC | May 7, 09:00 UTC | 10h 10m |
| 2026-05-06 | UAL923 | LAX → LHR | May 6, 22:48 UTC | May 7, 08:59 UTC | 10h 11m |
| 2026-05-06 | UAL2692 | IAD → PHL | May 6, 13:40 UTC | May 6, 18:55 UTC | 5h 14m |
| 2026-05-03 | UAL1855 | ORD → BOS | May 3, 20:30 UTC | May 4, 00:55 UTC | 4h 25m |
| 2026-05-03 | UAL99 | MEL → LAX | May 3, 00:20 UTC | May 3, 01:00 UTC | 40m |
| 2026-05-03 | UAL99 | MEL → LAX | May 3, 00:06 UTC | May 3, 13:22 UTC | 13h 16m |
| 2026-05-03 | UAL99 | MEL → LAX | May 3, 00:01 UTC | May 3, 00:15 UTC | 15m |
| 2026-05-02 | UAL98 | LAX → MEL | May 2, 06:00 UTC | May 2, 21:45 UTC | 15h 45m |
| 2026-05-01 | UAL199D | PVG → LAX | May 1, 14:50 UTC | May 1, 16:05 UTC | 1h 15m |
| 2026-05-01 | UAL199D | PVG → LAX | May 1, 06:35 UTC | May 2, 00:45 UTC | 18h 10m |
| 2026-05-01 | UAL199D | PVG → LAX | May 1, 01:05 UTC | May 2, 00:45 UTC | 23h 40m |
| 2026-04-30 | UAL198 | LAX → PVG | Apr 30, 21:05 UTC | May 1, 16:05 UTC | 19h 0m |
| 2026-04-30 | UAL198 | LAX → PVG | Apr 30, 20:25 UTC | May 1, 08:10 UTC | 11h 45m |
| 2026-04-30 | UAL198 | LAX → PVG | Apr 30, 20:08 UTC | May 1, 09:20 UTC | 13h 12m |
| 2026-04-30 | UAL33 | NRT → LAX | Apr 30, 08:00 UTC | Apr 30, 17:25 UTC | 9h 25m |
| 2026-04-29 | UAL79 | EWR → NRT | Apr 29, 16:10 UTC | Apr 30, 05:20 UTC | 13h 9m |
| 2026-04-28 | UAL187 | JNB → EWR | Apr 28, 20:20 UTC | Apr 28, 20:45 UTC | 25m |
| 2026-04-28 | UAL187 | JNB → EWR | Apr 28, 20:19 UTC | Apr 29, 12:23 UTC | 16h 4m |
| 2026-04-28 | UAL188 | EWR → JNB | Apr 28, 02:05 UTC | Apr 28, 16:10 UTC | 14h 5m |
| 2026-04-27 | UAL78 | NRT → EWR | Apr 27, 08:55 UTC | Apr 27, 09:30 UTC | 35m |
| 2026-04-27 | UAL78 | NRT → EWR | Apr 27, 08:51 UTC | Apr 27, 20:53 UTC | 12h 2m |
| 2026-04-26 | UAL143 | DEN → NRT | Apr 26, 18:25 UTC | Apr 27, 06:00 UTC | 11h 35m |
| 2026-04-25 | UAL761 | MUC → DEN | Apr 25, 14:30 UTC | Apr 26, 00:15 UTC | 9h 45m |
| 2026-04-25 | UAL760 | DEN → MUC | Apr 25, 02:35 UTC | Apr 25, 12:00 UTC | 9h 25m |
| 2026-04-24 | UAL178 | KIX → GUM | Apr 24, 13:05 UTC | Apr 24, 23:35 UTC | 10h 30m |
| 2026-04-24 | UAL177 | GUM → KIX | Apr 24, 00:23 UTC | Apr 24, 10:35 UTC | 10h 12m |
| 2026-04-24 | UAL177 | GUM → KIX | Apr 24, 00:20 UTC | Apr 24, 10:45 UTC | 10h 25m |
| 2026-04-23 | UAL26 | LHR → DEN | Apr 23, 11:05 UTC | Apr 23, 19:55 UTC | 8h 50m |
| 2026-04-23 | UAL26 | LHR → DEN | Apr 23, 10:50 UTC | Apr 23, 19:49 UTC | 8h 59m |
| 2026-04-23 | UAL27 | DEN → LHR | Apr 23, 00:05 UTC | Apr 23, 08:40 UTC | 8h 36m |
| 2026-04-22 | UAL26 | LHR → DEN | Apr 22, 10:50 UTC | Apr 22, 19:50 UTC | 9h 0m |
| 2026-04-21 | UAL27 | DEN → LHR | Apr 21, 23:58 UTC | Apr 22, 08:23 UTC | 8h 25m |
| 2026-04-21 | UAL27 | DEN → LHR | Apr 21, 23:50 UTC | Apr 22, 01:40 UTC | 1h 50m |
| 2026-04-21 | UAL181 | FRA → DEN | Apr 21, 09:40 UTC | Apr 21, 19:00 UTC | 9h 20m |
| 2026-04-20 | UAL182 | DEN → FRA | Apr 20, 22:00 UTC | Apr 21, 07:05 UTC | 9h 5m |
| 2026-04-20 | UAL142 | NRT → DEN | Apr 20, 08:10 UTC | Apr 20, 18:05 UTC | 9h 55m |
| 2026-04-19 | UAL143 | DEN → NRT | Apr 19, 18:05 UTC | Apr 20, 05:25 UTC | 11h 20m |
| 2026-04-18 | UAL761 | MUC → DEN | Apr 18, 14:30 UTC | Apr 19, 00:25 UTC | 9h 55m |
| 2026-04-18 | UAL760 | DEN → MUC | Apr 18, 03:25 UTC | Apr 18, 04:25 UTC | 1h 0m |
| 2026-04-18 | UAL760 | DEN → MUC | Apr 18, 02:50 UTC | Apr 18, 11:50 UTC | 9h 0m |
| 2026-04-17 | UAL263 | EWR → PBI | Apr 17, 21:25 UTC | Apr 17, 23:20 UTC | 1h 55m |
| 2026-04-17 | UAL263 | EWR → PBI | Apr 17, 21:00 UTC | Apr 17, 21:20 UTC | 20m |
| 2026-04-17 | UAL263 | EWR → PBI | Apr 17, 16:00 UTC | Apr 17, 16:35 UTC | 35m |
| 2026-04-17 | UAL263 | EWR → PBI | Apr 17, 14:10 UTC | Apr 17, 15:10 UTC | 59m |
| 2026-04-17 | UAL262 | DEN → LHR | Apr 17, 09:45 UTC | Apr 17, 11:05 UTC | 1h 20m |
| 2026-04-17 | UAL262 | DEN → LHR | Apr 17, 03:20 UTC | Apr 17, 04:35 UTC | 1h 16m |
| 2026-04-17 | UAL262 | DEN → LHR | Apr 17, 02:40 UTC | Apr 17, 10:53 UTC | 8h 13m |
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 N30PX page for operator, model, and routing details .