sensors Mode-S transponder
A2F2FA
ICAO 24-bit transponder address · allocated to United States
Currently assigned to N28987 · BOEING 787-9 Dreamliner · operated by UNITED AIRLINES INC
- Hex
- A2F2FA
- Octal
- 50571372
- Decimal
- 10,679,034
- Country
- US
- Tail
- N28987
- Type
- B789
- Flights observed
- 178
- Distinct callsigns
- 20
- Country
- US
- Last broadcast
- 3h ago
Last known position
Country allocation
The ICAO 24-bit address A2F2FA 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 |
|---|---|---|---|
| UAL29 | - | 8 | 2026-07-17 |
| UAL805 | - | 7 | 2026-07-15 |
| UAL870 | - | 6 | 2026-07-05 |
| UAL806 | - | 6 | 2026-07-16 |
| UAL115 | United Airlines | 6 | 2026-07-16 |
| UAL935 | - | 5 | 2026-07-03 |
| UAL770 | - | 5 | 2026-06-28 |
| UAL187 | United Airlines | 5 | 2026-05-23 |
| UAL152 | United Airlines | 5 | 2026-05-30 |
| UAL923 | - | 4 | 2026-07-02 |
| UAL820 | United Airlines | 4 | 2026-05-19 |
| UAL769 | - | 4 | 2026-06-28 |
| UAL28 | - | 4 | 2026-07-14 |
| UAL2023 | United Airlines | 4 | 2026-04-20 |
| UAL199 | United Airlines | 4 | 2026-06-01 |
| UAL198 | United Airlines | 4 | 2026-05-31 |
| UAL153 | United Airlines | 4 | 2026-05-31 |
| UAL114 | - | 4 | 2026-07-17 |
| UAL1011 | United Airlines | 4 | 2026-04-18 |
| UAL982 | United Airlines | 3 | 2026-06-17 |
Recent flights last 50
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-07-17 | UAL29 | - | Jul 17, 19:09 UTC | Jul 18, 10:25 UTC | 15h 16m |
| 2026-07-17 | UAL114 | - | Jul 17, 07:14 UTC | Jul 17, 14:50 UTC | 7h 35m |
| 2026-07-16 | UAL115 | SFO → PPT | Jul 16, 20:52 UTC | Jul 17, 04:51 UTC | 7h 59m |
| 2026-07-16 | UAL115 | SFO → PPT | Jul 16, 20:49 UTC | Jul 17, 04:59 UTC | 8h 10m |
| 2026-07-16 | UAL806 | - | Jul 16, 02:45 UTC | Jul 16, 13:10 UTC | 10h 25m |
| 2026-07-15 | UAL805 | SFO → ICN | Jul 15, 07:30 UTC | Jul 15, 18:50 UTC | 11h 20m |
| 2026-07-14 | UAL28 | - | Jul 14, 15:05 UTC | Jul 15, 04:40 UTC | 13h 34m |
| 2026-07-14 | UAL29 | - | Jul 14, 10:15 UTC | Jul 14, 10:25 UTC | 10m |
| 2026-07-13 | UAL29 | SFO → SIN | Jul 13, 18:35 UTC | Jul 14, 10:27 UTC | 15h 52m |
| 2026-07-13 | UAL29 | - | Jul 13, 18:50 UTC | Jul 14, 09:05 UTC | 14h 15m |
| 2026-07-13 | UAL114 | - | Jul 13, 07:45 UTC | Jul 13, 15:15 UTC | 7h 30m |
| 2026-07-12 | UAL115 | SFO → PPT | Jul 12, 20:52 UTC | Jul 13, 04:45 UTC | 7h 53m |
| 2026-07-12 | UAL115 | - | Jul 12, 20:55 UTC | Jul 12, 21:20 UTC | 25m |
| 2026-07-12 | UAL806 | ICN → SFO | Jul 12, 02:56 UTC | Jul 12, 12:57 UTC | 10h 1m |
| 2026-07-12 | UAL806 | - | Jul 12, 02:40 UTC | Jul 12, 04:25 UTC | 1h 45m |
| 2026-07-11 | UAL805 | - | Jul 11, 08:05 UTC | Jul 11, 19:15 UTC | 11h 10m |
| 2026-07-10 | UAL28 | - | Jul 10, 17:35 UTC | Jul 11, 05:31 UTC | 11h 56m |
| 2026-07-09 | UAL29 | SFO → SIN | Jul 9, 18:47 UTC | Jul 10, 10:29 UTC | 15h 42m |
| 2026-07-09 | UAL29 | - | Jul 9, 19:00 UTC | Jul 9, 19:25 UTC | 25m |
| 2026-07-09 | UAL806 | - | Jul 9, 02:45 UTC | Jul 9, 13:20 UTC | 10h 35m |
| 2026-07-08 | UAL805 | SFO → ICN | Jul 8, 07:35 UTC | Jul 8, 19:10 UTC | 11h 35m |
| 2026-07-07 | UAL969 | - | Jul 7, 13:40 UTC | Jul 8, 00:15 UTC | 10h 35m |
| 2026-07-06 | UAL968 | - | Jul 6, 22:30 UTC | Jul 7, 08:00 UTC | 9h 30m |
| 2026-07-06 | UAL892 | ICN → SFO | Jul 6, 08:16 UTC | Jul 6, 18:01 UTC | 9h 45m |
| 2026-07-06 | UAL892 | - | Jul 6, 08:00 UTC | Jul 6, 18:10 UTC | 10h 10m |
| 2026-07-05 | UAL893 | SFO → ICN | Jul 5, 18:10 UTC | Jul 6, 05:50 UTC | 11h 40m |
| 2026-07-05 | UAL870 | SYD → SFO | Jul 5, 01:15 UTC | Jul 5, 14:17 UTC | 13h 2m |
| 2026-07-05 | UAL870 | - | Jul 5, 01:15 UTC | Jul 5, 14:10 UTC | 12h 55m |
| 2026-07-04 | UAL839 | LAX → SYD | Jul 4, 06:00 UTC | Jul 4, 21:15 UTC | 15h 15m |
| 2026-07-03 | UAL935 | - | Jul 3, 12:40 UTC | Jul 3, 23:00 UTC | 10h 20m |
| 2026-07-03 | UAL935 | LHR → LAX | Jul 3, 12:30 UTC | Jul 3, 22:56 UTC | 10h 26m |
| 2026-07-02 | UAL923 | LAX → LHR | Jul 2, 23:20 UTC | Jul 3, 08:55 UTC | 9h 35m |
| 2026-06-30 | UAL935 | - | Jun 30, 12:35 UTC | Jun 30, 22:45 UTC | 10h 10m |
| 2026-06-29 | UAL923 | - | Jun 29, 22:59 UTC | Jun 30, 09:05 UTC | 10h 6m |
| 2026-06-29 | UAL923 | LAX → LHR | Jun 29, 22:53 UTC | Jun 30, 09:03 UTC | 10h 10m |
| 2026-06-29 | UAL2692 | - | Jun 29, 13:24 UTC | Jun 29, 18:25 UTC | 5h 0m |
| 2026-06-29 | UAL3923 | ORD → EWR | Jun 29, 10:04 UTC | Jun 29, 11:39 UTC | 1h 35m |
| 2026-06-28 | UAL770 | BCN → ORD | Jun 28, 13:59 UTC | Jun 28, 22:34 UTC | 8h 35m |
| 2026-06-28 | UAL769 | - | Jun 28, 04:20 UTC | Jun 28, 11:50 UTC | 7h 30m |
| 2026-06-27 | UAL3021 | BCN → ORD | Jun 27, 15:28 UTC | Jun 28, 00:16 UTC | 8h 48m |
| 2026-06-27 | UAL3021 | BCN → ORD | Jun 27, 15:28 UTC | Jun 28, 00:03 UTC | 8h 35m |
| 2026-06-27 | UAL3021 | - | Jun 27, 15:30 UTC | Jun 27, 17:44 UTC | 2h 15m |
| 2026-06-26 | UAL770 | BCN → BCN | Jun 26, 14:39 UTC | Jun 26, 16:39 UTC | 2h 0m |
| 2026-06-26 | UAL769 | ORD → BCN | Jun 26, 04:48 UTC | Jun 26, 12:14 UTC | 7h 26m |
| 2026-06-26 | UAL769 | ORD → BCN | Jun 26, 04:39 UTC | Jun 26, 12:10 UTC | 7h 30m |
| 2026-06-25 | UAL3780 | TPA → ORD | Jun 25, 21:16 UTC | Jun 25, 23:20 UTC | 2h 4m |
| 2026-06-25 | UAL3780 | TPA → ORD | Jun 25, 21:10 UTC | Jun 25, 23:39 UTC | 2h 30m |
| 2026-06-25 | UAL3774 | ORD → MSY | Jun 25, 16:55 UTC | Jun 25, 18:55 UTC | 2h 0m |
| 2026-06-24 | UAL770 | BCN → ORD | Jun 24, 13:41 UTC | Jun 24, 22:06 UTC | 8h 25m |
| 2026-06-24 | UAL770 | BCN → ORD | Jun 24, 13:41 UTC | Jun 24, 21:54 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 N28987 page for operator, model, and routing details .