sensors Mode-S transponder
A254D6
ICAO 24-bit transponder address · allocated to United States
Currently assigned to N24972 · BOEING 787-9 Dreamliner · operated by UNITED AIRLINES INC
- Hex
- A254D6
- Octal
- 50452326
- Decimal
- 10,638,550
- Country
- US
- Tail
- N24972
- Type
- B789
- Flights observed
- 208
- Distinct callsigns
- 20
- Country
- US
- Last broadcast
- 39m ago
Current position
Country allocation
The ICAO 24-bit address A254D6 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 |
|---|---|---|---|
| UAL2023 | - | 8 | 2026-07-07 |
| UAL143 | United Airlines | 7 | 2026-06-19 |
| UAL892 | - | 6 | 2026-07-01 |
| UAL78 | United Airlines | 6 | 2026-04-17 |
| UAL62 | - | 6 | 2026-06-14 |
| UAL198 | - | 6 | 2026-06-21 |
| UAL178 | United Airlines | 6 | 2026-06-17 |
| UAL1227 | - | 6 | 2026-07-10 |
| UAL1011 | - | 6 | 2026-07-07 |
| UAL893 | - | 5 | 2026-06-30 |
| UAL82 | United Airlines | 5 | 2026-04-21 |
| UAL28 | - | 5 | 2026-07-13 |
| UAL263 | - | 5 | 2026-06-18 |
| UAL262 | - | 5 | 2026-06-18 |
| UAL870 | - | 4 | 2026-06-25 |
| UAL805 | United Airlines | 4 | 2026-06-09 |
| UAL29 | - | 4 | 2026-07-12 |
| UAL27 | United Airlines | 4 | 2026-04-13 |
| UAL26 | United Airlines | 4 | 2026-04-13 |
| UAL2096 | - | 4 | 2026-07-09 |
Recent flights last 50
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-07-13 | UAL28 | - | Jul 13, 14:05 UTC | Jul 14, 03:30 UTC | 13h 25m |
| 2026-07-13 | UAL28 | SIN → SFO | Jul 13, 13:06 UTC | Jul 14, 04:05 UTC | 14h 59m |
| 2026-07-13 | UAL28 | - | Jul 13, 12:50 UTC | Jul 13, 13:00 UTC | 10m |
| 2026-07-12 | UAL29 | - | Jul 12, 18:40 UTC | Jul 13, 09:05 UTC | 14h 25m |
| 2026-07-11 | UAL949 | - | Jul 11, 13:30 UTC | Jul 11, 14:35 UTC | 1h 5m |
| 2026-07-11 | UAL949 | LHR → SFO | Jul 11, 12:55 UTC | Jul 11, 23:54 UTC | 10h 59m |
| 2026-07-11 | UAL949 | LHR → SFO | Jul 11, 12:55 UTC | Jul 12, 00:08 UTC | 11h 13m |
| 2026-07-11 | UAL948 | SFO → LHR | Jul 11, 01:25 UTC | Jul 11, 10:55 UTC | 9h 30m |
| 2026-07-10 | UAL1227 | - | Jul 10, 17:55 UTC | Jul 10, 23:20 UTC | 5h 25m |
| 2026-07-09 | UAL2096 | - | Jul 9, 15:35 UTC | Jul 9, 20:15 UTC | 4h 40m |
| 2026-07-09 | UAL353 | - | Jul 9, 03:35 UTC | Jul 9, 08:10 UTC | 4h 35m |
| 2026-07-08 | UAL3888 | - | Jul 8, 11:20 UTC | Jul 8, 12:00 UTC | 40m |
| 2026-07-07 | UAL2023 | CPT → IAD | Jul 7, 18:21 UTC | Jul 8, 09:12 UTC | 14h 51m |
| 2026-07-07 | UAL2023 | - | Jul 7, 18:10 UTC | Jul 8, 02:00 UTC | 7h 50m |
| 2026-07-07 | UAL1011 | IAD → CPT | Jul 7, 00:10 UTC | Jul 7, 14:10 UTC | 14h 0m |
| 2026-07-06 | UAL3933 | EWR → IAD | Jul 6, 18:07 UTC | Jul 6, 19:16 UTC | 1h 9m |
| 2026-07-06 | UAL3933 | EWR → IAD | Jul 6, 18:30 UTC | Jul 6, 19:15 UTC | 45m |
| 2026-07-05 | UAL2096 | LAX → EWR | Jul 5, 15:40 UTC | Jul 5, 20:20 UTC | 4h 40m |
| 2026-07-04 | UAL935 | - | Jul 4, 13:15 UTC | Jul 4, 23:40 UTC | 10h 25m |
| 2026-07-04 | UAL948 | SFO → LHR | Jul 4, 00:44 UTC | Jul 4, 10:28 UTC | 9h 44m |
| 2026-07-04 | UAL948 | - | Jul 4, 00:50 UTC | Jul 4, 10:40 UTC | 9h 50m |
| 2026-07-02 | UAL969 | AMS → SFO | Jul 2, 13:21 UTC | Jul 2, 23:30 UTC | 10h 9m |
| 2026-07-02 | UAL969 | - | Jul 2, 13:20 UTC | Jul 2, 17:30 UTC | 4h 10m |
| 2026-07-01 | UAL968 | - | Jul 1, 22:40 UTC | Jul 2, 08:10 UTC | 9h 30m |
| 2026-07-01 | UAL892 | ICN → SFO | Jul 1, 08:05 UTC | Jul 1, 18:00 UTC | 9h 55m |
| 2026-06-30 | UAL893 | SFO → ICN | Jun 30, 18:15 UTC | Jul 1, 05:50 UTC | 11h 35m |
| 2026-06-30 | UAL61 | - | Jun 30, 02:05 UTC | Jun 30, 02:35 UTC | 30m |
| 2026-06-30 | UAL61 | MEL → SFO | Jun 30, 01:29 UTC | Jun 30, 14:57 UTC | 13h 28m |
| 2026-06-30 | UAL61 | - | Jun 30, 01:30 UTC | Jun 30, 01:55 UTC | 25m |
| 2026-06-29 | UAL60 | SFO → MEL | Jun 29, 07:16 UTC | Jun 29, 22:16 UTC | 15h 0m |
| 2026-06-29 | UAL60 | - | Jun 29, 07:20 UTC | Jun 29, 07:55 UTC | 35m |
| 2026-06-28 | UAL28 | - | Jun 28, 16:05 UTC | Jun 29, 05:04 UTC | 13h 0m |
| 2026-06-28 | UAL28 | SIN → SFO | Jun 28, 14:31 UTC | Jun 29, 04:59 UTC | 14h 28m |
| 2026-06-28 | UAL29 | - | Jun 28, 11:55 UTC | Jun 28, 12:09 UTC | 15m |
| 2026-06-27 | UAL29 | SFO → SIN | Jun 27, 20:25 UTC | Jun 28, 12:11 UTC | 15h 46m |
| 2026-06-27 | UAL29 | - | Jun 27, 20:44 UTC | Jun 28, 10:50 UTC | 14h 5m |
| 2026-06-27 | UAL114 | - | Jun 27, 07:15 UTC | Jun 27, 15:05 UTC | 7h 50m |
| 2026-06-26 | UAL115 | SFO → PPT | Jun 26, 21:07 UTC | Jun 27, 04:54 UTC | 7h 47m |
| 2026-06-26 | UAL115 | SFO → PPT | Jun 26, 21:04 UTC | Jun 27, 04:54 UTC | 7h 50m |
| 2026-06-26 | UAL114 | - | Jun 26, 07:10 UTC | Jun 26, 14:55 UTC | 7h 45m |
| 2026-06-25 | UAL115 | SFO → PPT | Jun 25, 20:49 UTC | Jun 26, 04:50 UTC | 8h 0m |
| 2026-06-25 | UAL870 | - | Jun 25, 01:19 UTC | Jun 25, 13:59 UTC | 12h 40m |
| 2026-06-24 | UAL839 | - | Jun 24, 06:15 UTC | Jun 24, 21:04 UTC | 14h 50m |
| 2026-06-23 | UAL821 | - | Jun 23, 14:29 UTC | Jun 24, 03:04 UTC | 12h 35m |
| 2026-06-23 | UAL821 | - | Jun 23, 09:34 UTC | Jun 23, 11:49 UTC | 2h 15m |
| 2026-06-23 | UAL820 | HKG → BKK | Jun 23, 00:19 UTC | Jun 23, 02:34 UTC | 2h 15m |
| 2026-06-22 | UAL820 | - | Jun 22, 07:30 UTC | Jun 22, 21:49 UTC | 14h 20m |
| 2026-06-21 | UAL199 | PVG → LAX | Jun 21, 13:20 UTC | Jun 21, 14:54 UTC | 1h 35m |
| 2026-06-21 | UAL199 | PVG → LAX | Jun 21, 06:14 UTC | Jun 21, 23:44 UTC | 17h 30m |
| 2026-06-21 | UAL198 | - | Jun 21, 00:45 UTC | Jun 21, 23:30 UTC | 22h 45m |
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 N24972 page for operator, model, and routing details .