sensors Mode-S transponder
A254DA
ICAO 24-bit transponder address · allocated to United States
Currently assigned to N24976 · BOEING 787-9 Dreamliner · operated by UNITED AIRLINES INC
- Hex
- A254DA
- Octal
- 50452332
- Decimal
- 10,638,554
- Country
- US
- Tail
- N24976
- Type
- B789
- Flights observed
- 173
- Distinct callsigns
- 20
- Country
- US
- Last broadcast
- Jul 26, 22:30 UTC
Current position
Country allocation
The ICAO 24-bit address A254DA 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 |
|---|---|---|---|
| UAL82 | United Airlines | 10 | 2026-07-20 |
| UAL713 | - | 9 | 2026-07-19 |
| UAL820 | - | 8 | 2026-07-11 |
| UAL187 | - | 8 | 2026-07-14 |
| UAL83 | United Airlines | 7 | 2026-06-21 |
| UAL821 | - | 7 | 2026-07-11 |
| UAL115 | - | 7 | 2026-06-29 |
| UAL60 | - | 6 | 2026-07-02 |
| UAL29 | - | 6 | 2026-07-17 |
| UAL28 | - | 6 | 2026-07-17 |
| UAL188 | - | 6 | 2026-07-14 |
| UAL892 | United Airlines | 5 | 2026-05-17 |
| UAL870 | United Airlines | 5 | 2026-07-25 |
| UAL1227 | - | 5 | 2026-07-15 |
| UAL996 | - | 4 | 2026-06-16 |
| UAL893 | United Airlines | 4 | 2026-05-16 |
| UAL863 | - | 4 | 2026-06-27 |
| UAL61 | - | 4 | 2026-07-03 |
| UAL114 | - | 4 | 2026-06-29 |
| UAL997 | - | 3 | 2026-06-17 |
Recent flights last 50
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-07-26 | UAL949 | LHR → SFO | Jul 26, 12:25 UTC | Jul 26, 22:37 UTC | 10h 12m |
| 2026-07-26 | UAL949 | LHR → SFO | Jul 26, 12:10 UTC | Jul 26, 12:30 UTC | 20m |
| 2026-07-26 | UAL948 | SFO → LHR | Jul 26, 00:14 UTC | Jul 26, 09:32 UTC | 9h 18m |
| 2026-07-26 | UAL948 | SFO → LHR | Jul 26, 00:20 UTC | Jul 26, 09:35 UTC | 9h 16m |
| 2026-07-25 | UAL870 | SYD → SFO | Jul 25, 01:15 UTC | Jul 25, 14:10 UTC | 12h 55m |
| 2026-07-24 | UAL839 | LAX → SYD | Jul 24, 07:25 UTC | Jul 24, 21:55 UTC | 14h 30m |
| 2026-07-23 | UAL353 | SAN → EWR | Jul 23, 23:40 UTC | Jul 24, 04:30 UTC | 4h 50m |
| 2026-07-22 | UAL3975 | HNL → SIN | Jul 22, 19:50 UTC | Jul 23, 00:30 UTC | 4h 40m |
| 2026-07-22 | UAL3975 | HNL → SIN | Jul 22, 19:55 UTC | Jul 23, 11:34 UTC | 15h 39m |
| 2026-07-20 | UAL82 | EWR → DEL | Jul 20, 02:55 UTC | Jul 20, 16:35 UTC | 13h 40m |
| 2026-07-19 | UAL713 | - | Jul 19, 19:00 UTC | Jul 20, 00:00 UTC | 5h 0m |
| 2026-07-19 | UAL806 | ICN → SFO | Jul 19, 02:40 UTC | Jul 19, 13:10 UTC | 10h 30m |
| 2026-07-18 | UAL805 | SFO → ICN | Jul 18, 07:55 UTC | Jul 18, 18:50 UTC | 10h 55m |
| 2026-07-17 | UAL28 | SIN → SFO | Jul 17, 16:29 UTC | Jul 18, 05:00 UTC | 12h 31m |
| 2026-07-17 | UAL28 | - | Jul 17, 13:35 UTC | Jul 17, 13:45 UTC | 10m |
| 2026-07-17 | UAL29 | - | Jul 17, 10:40 UTC | Jul 17, 10:50 UTC | 10m |
| 2026-07-16 | UAL29 | - | Jul 16, 19:14 UTC | Jul 17, 08:59 UTC | 13h 45m |
| 2026-07-16 | UAL29 | SFO → SIN | Jul 16, 18:35 UTC | Jul 17, 10:47 UTC | 16h 12m |
| 2026-07-15 | UAL1227 | EWR → SFO | Jul 15, 17:50 UTC | Jul 15, 22:45 UTC | 4h 55m |
| 2026-07-14 | UAL187 | - | Jul 14, 20:05 UTC | Jul 15, 11:00 UTC | 14h 54m |
| 2026-07-14 | UAL188 | EWR → JNB | Jul 14, 01:54 UTC | Jul 14, 16:27 UTC | 14h 33m |
| 2026-07-14 | UAL188 | - | Jul 14, 01:45 UTC | Jul 14, 02:20 UTC | 35m |
| 2026-07-13 | UAL713 | SFO → EWR | Jul 13, 17:40 UTC | Jul 13, 22:40 UTC | 5h 0m |
| 2026-07-13 | UAL870 | SYD → SFO | Jul 13, 00:50 UTC | Jul 13, 13:45 UTC | 12h 55m |
| 2026-07-12 | UAL839 | - | Jul 12, 06:35 UTC | Jul 12, 20:40 UTC | 14h 5m |
| 2026-07-11 | UAL821 | HKG → LAX | Jul 11, 13:55 UTC | Jul 12, 03:05 UTC | 13h 10m |
| 2026-07-11 | UAL821 | - | Jul 11, 11:15 UTC | Jul 11, 11:30 UTC | 15m |
| 2026-07-11 | UAL821 | - | Jul 11, 09:20 UTC | Jul 11, 09:30 UTC | 10m |
| 2026-07-11 | UAL821 | BKK → HKG | Jul 11, 09:05 UTC | Jul 11, 11:33 UTC | 2h 28m |
| 2026-07-11 | UAL820 | - | Jul 11, 02:35 UTC | Jul 11, 03:05 UTC | 30m |
| 2026-07-11 | UAL820 | - | Jul 11, 00:50 UTC | Jul 11, 01:05 UTC | 15m |
| 2026-07-10 | UAL820 | - | Jul 10, 07:45 UTC | Jul 10, 22:15 UTC | 14h 31m |
| 2026-07-10 | UAL820 | LAX → HKG | Jul 10, 07:32 UTC | Jul 10, 22:06 UTC | 14h 34m |
| 2026-07-10 | UAL353T | - | Jul 10, 00:10 UTC | Jul 10, 05:05 UTC | 4h 55m |
| 2026-07-09 | UAL353T | EWR → LAX | Jul 9, 23:19 UTC | Jul 10, 05:00 UTC | 5h 41m |
| 2026-07-07 | UAL187 | - | Jul 7, 15:55 UTC | Jul 7, 17:10 UTC | 1h 15m |
| 2026-07-07 | UAL187 | SJU → EWR | Jul 7, 13:49 UTC | Jul 7, 17:09 UTC | 3h 20m |
| 2026-07-06 | UAL187 | JNB → SJU | Jul 6, 23:15 UTC | Jul 7, 12:08 UTC | 12h 53m |
| 2026-07-06 | UAL187 | - | Jul 6, 22:55 UTC | Jul 6, 23:20 UTC | 25m |
| 2026-07-06 | UAL188 | EWR → JNB | Jul 6, 04:50 UTC | Jul 6, 19:00 UTC | 14h 10m |
| 2026-07-05 | UAL713 | SFO → EWR | Jul 5, 17:40 UTC | Jul 5, 22:20 UTC | 4h 40m |
| 2026-07-04 | UAL1227 | EWR → SFO | Jul 4, 19:45 UTC | Jul 5, 00:55 UTC | 5h 10m |
| 2026-07-04 | UAL3019 | - | Jul 4, 16:45 UTC | Jul 4, 17:45 UTC | 1h 0m |
| 2026-07-03 | UAL713 | SFO → CLE | Jul 3, 17:50 UTC | Jul 3, 23:30 UTC | 5h 40m |
| 2026-07-03 | UAL713 | SFO → CLE | Jul 3, 17:50 UTC | Jul 3, 23:30 UTC | 5h 40m |
| 2026-07-03 | UAL61 | - | Jul 3, 01:10 UTC | Jul 3, 14:50 UTC | 13h 40m |
| 2026-07-02 | UAL60 | SFO → MEL | Jul 2, 07:01 UTC | Jul 2, 22:10 UTC | 15h 9m |
| 2026-07-02 | UAL60 | - | Jul 2, 07:10 UTC | Jul 2, 22:15 UTC | 15h 5m |
| 2026-07-01 | UAL1757 | - | Jul 1, 22:20 UTC | Jul 2, 03:15 UTC | 4h 55m |
| 2026-07-01 | UAL1849 | MCO → EWR | Jul 1, 15:25 UTC | Jul 1, 20:00 UTC | 4h 35m |
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 N24976 page for operator, model, and routing details .