sensors Mode-S transponder
A1F1A0
ICAO 24-bit transponder address · allocated to United States
Currently assigned to N224UA · BOEING 777-200 · operated by UNITED AIRLINES INC
- Hex
- A1F1A0
- Octal
- 50370640
- Decimal
- 10,613,152
- Country
- US
- Tail
- N224UA
- Type
- B772
- Flights observed
- 78
- Distinct callsigns
- 20
- Country
- US
- Last broadcast
- 8h ago
Last known position
Country allocation
The ICAO 24-bit address A1F1A0 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 |
|---|---|---|---|
| UAL915 | United Airlines | 4 | 2026-05-22 |
| UAL804 | United Airlines | 4 | 2026-04-21 |
| UAL3870 | United Airlines | 4 | 2026-05-17 |
| UAL131 | United Airlines | 4 | 2026-04-28 |
| UAL97 | United Airlines | 3 | 2026-04-15 |
| UAL852 | United Airlines | 3 | 2026-05-18 |
| UAL34 | United Airlines | 3 | 2026-04-16 |
| UAL23 | United Airlines | 3 | 2026-05-26 |
| UAL22 | United Airlines | 3 | 2026-05-26 |
| UAL96 | United Airlines | 2 | 2026-04-14 |
| UAL942 | United Airlines | 2 | 2026-05-22 |
| UAL914 | United Airlines | 2 | 2026-05-19 |
| UAL885 | United Airlines | 2 | 2026-05-21 |
| UAL853 | United Airlines | 2 | 2026-05-17 |
| UAL71 | United Airlines | 2 | 2026-05-24 |
| UAL70 | United Airlines | 2 | 2026-05-23 |
| UAL57 | United Airlines | 2 | 2026-05-26 |
| UAL56 | United Airlines | 2 | 2026-05-23 |
| UAL54 | United Airlines | 2 | 2026-05-25 |
| UAL46 | United Airlines | 2 | 2026-05-29 |
Recent flights last 50
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-05-29 | UAL47 | FRA → IAH | May 29, 13:20 UTC | May 29, 23:10 UTC | 9h 50m |
| 2026-05-29 | UAL46 | IAH → FRA | May 29, 00:25 UTC | May 29, 02:45 UTC | 2h 20m |
| 2026-05-29 | UAL46 | IAH → FRA | May 29, 00:28 UTC | May 29, 09:40 UTC | 9h 12m |
| 2026-05-28 | UAL160 | MUC → IAH | May 28, 10:30 UTC | May 28, 20:50 UTC | 10h 20m |
| 2026-05-27 | UAL194 | SFO → MUC | May 27, 21:34 UTC | May 28, 08:12 UTC | 10h 38m |
| 2026-05-27 | UAL194 | SFO → MUC | May 27, 21:40 UTC | May 28, 05:30 UTC | 7h 50m |
| 2026-05-27 | UAL984 | CDG → SFO | May 27, 07:40 UTC | May 27, 18:25 UTC | 10h 45m |
| 2026-05-26 | UAL57 | EWR → CDG | May 26, 22:25 UTC | May 27, 05:04 UTC | 6h 40m |
| 2026-05-26 | UAL57 | EWR → CDG | May 26, 22:13 UTC | May 27, 05:06 UTC | 6h 53m |
| 2026-05-26 | UAL22 | DUB → EWR | May 26, 09:19 UTC | May 26, 15:49 UTC | 6h 30m |
| 2026-05-26 | UAL23 | EWR → DUB | May 26, 01:35 UTC | May 26, 06:59 UTC | 5h 24m |
| 2026-05-26 | UAL23 | EWR → DUB | May 26, 01:40 UTC | May 26, 07:10 UTC | 5h 30m |
| 2026-05-25 | UAL55 | CDG → EWR | May 25, 13:55 UTC | May 25, 21:19 UTC | 7h 24m |
| 2026-05-25 | UAL54 | EWR → CDG | May 25, 01:55 UTC | May 25, 03:30 UTC | 1h 35m |
| 2026-05-25 | UAL54 | EWR → CDG | May 25, 02:04 UTC | May 25, 08:23 UTC | 6h 19m |
| 2026-05-24 | UAL71 | AMS → EWR | May 24, 07:27 UTC | May 24, 14:36 UTC | 7h 9m |
| 2026-05-24 | UAL71 | AMS → EWR | May 24, 07:20 UTC | May 24, 08:40 UTC | 1h 20m |
| 2026-05-23 | UAL70 | EWR → AMS | May 23, 22:28 UTC | May 24, 05:06 UTC | 6h 38m |
| 2026-05-23 | UAL70 | EWR → AMS | May 23, 22:35 UTC | May 24, 00:05 UTC | 1h 30m |
| 2026-05-23 | UAL56 | CDG → EWR | May 23, 08:05 UTC | May 23, 15:35 UTC | 7h 30m |
| 2026-05-22 | UAL915 | IAD → CDG | May 22, 22:31 UTC | May 23, 05:09 UTC | 6h 38m |
| 2026-05-22 | UAL915 | IAD → CDG | May 22, 22:45 UTC | May 23, 05:10 UTC | 6h 24m |
| 2026-05-22 | UAL943 | LIS → IAD | May 22, 11:45 UTC | May 22, 19:20 UTC | 7h 35m |
| 2026-05-22 | UAL942 | IAD → LIS | May 22, 02:58 UTC | May 22, 09:12 UTC | 6h 14m |
| 2026-05-22 | UAL942 | IAD → LIS | May 22, 03:15 UTC | May 22, 09:20 UTC | 6h 5m |
| 2026-05-21 | UAL885 | FCO → IAD | May 21, 09:40 UTC | May 21, 12:00 UTC | 2h 20m |
| 2026-05-21 | UAL885 | FCO → IAD | May 21, 09:42 UTC | May 21, 18:48 UTC | 9h 6m |
| 2026-05-20 | UAL884 | IAD → FCO | May 20, 23:10 UTC | May 21, 07:20 UTC | 8h 10m |
| 2026-05-19 | UAL914 | CDG → IAD | May 19, 10:45 UTC | May 19, 18:25 UTC | 7h 40m |
| 2026-05-19 | UAL914 | CDG → IAD | May 19, 10:49 UTC | May 19, 18:24 UTC | 7h 35m |
| 2026-05-18 | UAL990 | SFO → CDG | May 18, 22:15 UTC | May 19, 08:25 UTC | 10h 10m |
| 2026-05-18 | UAL852 | TPE → SAN | May 18, 08:05 UTC | May 18, 09:25 UTC | 1h 20m |
| 2026-05-18 | UAL852 | TPE → SAN | May 18, 06:51 UTC | May 18, 17:33 UTC | 10h 42m |
| 2026-05-18 | UAL852 | TPE → SAN | May 18, 06:35 UTC | May 18, 06:45 UTC | 10m |
| 2026-05-17 | UAL853 | SFO → TPE | May 17, 19:15 UTC | May 17, 19:40 UTC | 25m |
| 2026-05-17 | UAL853 | SFO → TPE | May 17, 07:30 UTC | May 17, 18:10 UTC | 10h 40m |
| 2026-05-17 | UAL3870 | IAB → SFO | May 17, 05:15 UTC | May 17, 05:20 UTC | 5m |
| 2026-05-16 | UAL3870 | IAB → SFO | May 16, 18:20 UTC | May 16, 23:30 UTC | 5h 10m |
| 2026-05-16 | UAL3870 | IAB → SFO | May 16, 16:10 UTC | May 16, 16:20 UTC | 10m |
| 2026-05-16 | UAL3870 | IAB → SFO | May 16, 15:45 UTC | May 17, 05:00 UTC | 13h 15m |
| 2026-04-30 | UAL3938 | SEA → SFO | Apr 30, 01:59 UTC | Apr 30, 13:40 UTC | 11h 41m |
| 2026-04-30 | UAL3938 | SEA → SFO | Apr 30, 01:50 UTC | Apr 30, 13:40 UTC | 11h 50m |
| 2026-04-29 | UAL876 | HND → SFO | Apr 29, 07:10 UTC | Apr 29, 16:05 UTC | 8h 56m |
| 2026-04-28 | UAL131 | EWR → HND | Apr 28, 14:28 UTC | Apr 29, 04:22 UTC | 13h 54m |
| 2026-04-28 | UAL131 | EWR → HND | Apr 28, 14:40 UTC | Apr 29, 04:25 UTC | 13h 45m |
| 2026-04-27 | UAL2397 | EWR → PDX | Apr 27, 04:25 UTC | Apr 27, 08:55 UTC | 4h 30m |
| 2026-04-26 | UAL2238 | IAH → SFO | Apr 26, 20:10 UTC | Apr 27, 01:35 UTC | 5h 25m |
| 2026-04-26 | UAL698 | DFW → EWR | Apr 26, 04:40 UTC | Apr 26, 09:15 UTC | 4h 35m |
| 2026-04-25 | UAL2004 | ORD → SFO | Apr 25, 20:28 UTC | Apr 26, 02:08 UTC | 5h 40m |
| 2026-04-25 | UAL2004 | ORD → SFO | Apr 25, 20:30 UTC | Apr 26, 02:10 UTC | 5h 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 N224UA page for operator, model, and routing details .