sensors Mode-S transponder
AA9321
ICAO 24-bit transponder address · allocated to United States
Currently assigned to N78017 · BOEING 777-200 · operated by UNITED AIRLINES INC
- Hex
- AA9321
- Octal
- 52511441
- Decimal
- 11,178,785
- Country
- US
- Tail
- N78017
- Type
- B772
- Flights observed
- 217
- Distinct callsigns
- 20
- Country
- US
- Last broadcast
- 19h ago
Last known position
Country allocation
The ICAO 24-bit address AA9321 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 |
|---|---|---|---|
| UAL888 | United Airlines | 12 | 2026-05-28 |
| UAL932 | - | 11 | 2026-06-28 |
| UAL933 | - | 10 | 2026-06-28 |
| UAL130 | - | 10 | 2026-07-12 |
| UAL803 | - | 9 | 2026-07-11 |
| UAL96 | - | 8 | 2026-07-06 |
| UAL889 | United Airlines | 8 | 2026-05-29 |
| UAL804 | - | 7 | 2026-07-08 |
| UAL97 | - | 6 | 2026-07-07 |
| UAL875 | - | 6 | 2026-07-07 |
| UAL506 | - | 6 | 2026-07-05 |
| UAL45 | United Airlines | 6 | 2026-06-24 |
| UAL131 | - | 6 | 2026-06-22 |
| UAL918 | United Airlines | 5 | 2026-06-13 |
| UAL916 | United Airlines | 5 | 2026-06-04 |
| UAL507 | - | 5 | 2026-07-05 |
| UAL44 | United Airlines | 5 | 2026-06-23 |
| UAL939 | United Airlines | 4 | 2026-04-27 |
| UAL927 | United Airlines | 4 | 2026-05-18 |
| UAL925 | United Airlines | 4 | 2026-04-14 |
Recent flights last 50
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-07-13 | UAL55 | - | Jul 13, 11:40 UTC | Jul 13, 18:55 UTC | 7h 15m |
| 2026-07-13 | UAL54 | EWR → CDG | Jul 13, 02:15 UTC | Jul 13, 08:50 UTC | 6h 35m |
| 2026-07-13 | UAL54 | EWR → CDG | Jul 13, 02:04 UTC | Jul 13, 08:46 UTC | 6h 42m |
| 2026-07-12 | UAL130 | - | Jul 12, 09:25 UTC | Jul 12, 16:15 UTC | 6h 50m |
| 2026-07-12 | UAL130 | HND → EWR | Jul 12, 09:10 UTC | Jul 12, 21:45 UTC | 12h 35m |
| 2026-07-11 | UAL803 | - | Jul 11, 17:10 UTC | Jul 12, 00:20 UTC | 7h 10m |
| 2026-07-11 | UAL803 | IAD → HND | Jul 11, 17:10 UTC | Jul 12, 06:27 UTC | 13h 17m |
| 2026-07-11 | UAL3902 | EWR → IAD | Jul 11, 12:20 UTC | Jul 11, 13:05 UTC | 45m |
| 2026-07-10 | UAL130 | HND → EWR | Jul 10, 13:45 UTC | Jul 11, 02:40 UTC | 12h 55m |
| 2026-07-09 | UAL803 | IAD → HND | Jul 9, 22:15 UTC | Jul 10, 11:30 UTC | 13h 15m |
| 2026-07-08 | UAL804 | HND → IAD | Jul 8, 07:10 UTC | Jul 8, 19:09 UTC | 11h 59m |
| 2026-07-08 | UAL804 | - | Jul 8, 07:05 UTC | Jul 8, 07:45 UTC | 40m |
| 2026-07-07 | UAL875 | SFO → HND | Jul 7, 18:40 UTC | Jul 8, 04:45 UTC | 10h 5m |
| 2026-07-07 | UAL97 | BNE → SFO | Jul 7, 00:43 UTC | Jul 7, 12:58 UTC | 12h 15m |
| 2026-07-07 | UAL97 | - | Jul 7, 00:40 UTC | Jul 7, 13:00 UTC | 12h 20m |
| 2026-07-06 | UAL96 | SFO → BNE | Jul 6, 07:06 UTC | Jul 6, 20:55 UTC | 13h 49m |
| 2026-07-06 | UAL96 | SFO → BNE | Jul 6, 07:10 UTC | Jul 6, 21:00 UTC | 13h 50m |
| 2026-07-05 | UAL506 | - | Jul 5, 14:05 UTC | Jul 6, 02:20 UTC | 12h 15m |
| 2026-07-05 | UAL507 | SFO → FCO | Jul 5, 00:10 UTC | Jul 5, 11:05 UTC | 10h 55m |
| 2026-07-04 | UAL876 | HND → SFO | Jul 4, 07:15 UTC | Jul 4, 16:14 UTC | 8h 59m |
| 2026-07-04 | UAL876 | - | Jul 4, 07:10 UTC | Jul 4, 16:25 UTC | 9h 15m |
| 2026-07-03 | UAL875 | SFO → HND | Jul 3, 18:25 UTC | Jul 4, 04:56 UTC | 10h 31m |
| 2026-07-03 | UAL875 | - | Jul 3, 18:30 UTC | Jul 4, 04:15 UTC | 9h 45m |
| 2026-07-03 | UAL97 | - | Jul 3, 00:55 UTC | Jul 3, 13:10 UTC | 12h 15m |
| 2026-07-02 | UAL96 | SFO → BNE | Jul 2, 07:06 UTC | Jul 2, 20:18 UTC | 13h 12m |
| 2026-07-02 | UAL96 | - | Jul 2, 07:00 UTC | Jul 2, 07:30 UTC | 30m |
| 2026-07-01 | UAL2328 | - | Jul 1, 19:10 UTC | Jul 2, 00:25 UTC | 5h 15m |
| 2026-06-30 | UAL130 | HND → EWR | Jun 30, 09:20 UTC | Jun 30, 21:40 UTC | 12h 20m |
| 2026-06-29 | UAL803 | IAD → HND | Jun 29, 17:19 UTC | Jun 30, 06:35 UTC | 13h 16m |
| 2026-06-28 | UAL933 | FRA → IAD | Jun 28, 15:40 UTC | Jun 28, 23:39 UTC | 8h 0m |
| 2026-06-28 | UAL933 | FRA → IAD | Jun 28, 15:31 UTC | Jun 28, 23:35 UTC | 8h 4m |
| 2026-06-28 | UAL932 | IAD → FRA | Jun 28, 03:28 UTC | Jun 28, 10:43 UTC | 7h 15m |
| 2026-06-28 | UAL932 | - | Jun 28, 03:25 UTC | Jun 28, 05:15 UTC | 1h 50m |
| 2026-06-27 | UAL933 | FRA → IAD | Jun 27, 16:04 UTC | Jun 27, 23:50 UTC | 7h 45m |
| 2026-06-27 | UAL932 | IAD → FRA | Jun 27, 03:04 UTC | Jun 27, 10:14 UTC | 7h 10m |
| 2026-06-27 | UAL932 | IAD → FRA | Jun 27, 02:47 UTC | Jun 27, 10:08 UTC | 7h 21m |
| 2026-06-26 | UAL933 | FRA → IAD | Jun 26, 15:45 UTC | Jun 26, 23:55 UTC | 8h 10m |
| 2026-06-26 | UAL933 | FRA → IAD | Jun 26, 15:31 UTC | Jun 26, 23:53 UTC | 8h 22m |
| 2026-06-26 | UAL932 | - | Jun 26, 03:15 UTC | Jun 26, 04:59 UTC | 1h 45m |
| 2026-06-26 | UAL932 | IAD → FRA | Jun 26, 02:33 UTC | Jun 26, 10:28 UTC | 7h 55m |
| 2026-06-25 | UAL933 | FRA → IAD | Jun 25, 15:44 UTC | Jun 25, 23:59 UTC | 8h 15m |
| 2026-06-25 | UAL926 | SFO → FRA | Jun 25, 02:39 UTC | Jun 25, 12:50 UTC | 10h 10m |
| 2026-06-24 | UAL45 | ZRH → SFO | Jun 24, 12:12 UTC | Jun 24, 23:25 UTC | 11h 13m |
| 2026-06-24 | UAL45 | ZRH → SFO | Jun 24, 12:14 UTC | Jun 24, 14:15 UTC | 2h 0m |
| 2026-06-23 | UAL44 | SFO → ZRH | Jun 23, 21:54 UTC | Jun 24, 08:20 UTC | 10h 25m |
| 2026-06-23 | UAL876 | - | Jun 23, 06:59 UTC | Jun 23, 16:14 UTC | 9h 15m |
| 2026-06-22 | UAL131 | EWR → HND | Jun 22, 14:53 UTC | Jun 23, 04:01 UTC | 13h 8m |
| 2026-06-22 | UAL131 | EWR → HND | Jun 22, 14:59 UTC | Jun 23, 04:00 UTC | 13h 0m |
| 2026-06-22 | UAL8241 | LAX → ORD | Jun 22, 06:06 UTC | Jun 22, 10:34 UTC | 4h 28m |
| 2026-06-22 | UAL8241 | LAX → ORD | Jun 22, 06:05 UTC | Jun 22, 10:44 UTC | 4h 40m |
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 N78017 page for operator, model, and routing details .