sensors Mode-S transponder
A596B1
ICAO 24-bit transponder address · allocated to United States
Currently assigned to N45956 · BOEING 787-9 Dreamliner · operated by UNITED AIRLINES INC
- Hex
- A596B1
- Octal
- 51313261
- Decimal
- 10,852,017
- Country
- US
- Tail
- N45956
- Type
- B789
- Flights observed
- 218
- Distinct callsigns
- 20
- Country
- US
- Last broadcast
- 8h ago
Last known position
Country allocation
The ICAO 24-bit address A596B1 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 |
|---|---|---|---|
| UAL199 | United Airlines | 13 | 2026-06-28 |
| UAL198 | - | 12 | 2026-06-15 |
| UAL153 | United Airlines | 12 | 2026-06-21 |
| UAL26 | United Airlines | 11 | 2026-06-03 |
| UAL182 | United Airlines | 11 | 2026-05-31 |
| UAL152 | United Airlines | 11 | 2026-06-20 |
| UAL178 | United Airlines | 10 | 2026-06-04 |
| UAL27 | United Airlines | 9 | 2026-06-03 |
| UAL181 | United Airlines | 8 | 2026-06-01 |
| UAL143 | United Airlines | 8 | 2026-06-07 |
| UAL262 | United Airlines | 7 | 2026-06-05 |
| UAL177 | United Airlines | 7 | 2026-06-04 |
| UAL761 | United Airlines | 6 | 2026-06-06 |
| UAL142 | United Airlines | 6 | 2026-05-31 |
| UAL771 | United Airlines | 5 | 2026-04-17 |
| UAL760 | United Airlines | 5 | 2026-06-06 |
| UAL263 | United Airlines | 5 | 2026-06-05 |
| UAL187 | - | 5 | 2026-07-08 |
| UAL98 | United Airlines | 4 | 2026-04-14 |
| UAL935 | - | 3 | 2026-06-22 |
Recent flights last 50
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-07-13 | UAL1227 | EWR → SFO | Jul 13, 17:45 UTC | Jul 13, 22:40 UTC | 4h 55m |
| 2026-07-13 | UAL123 | - | Jul 13, 07:15 UTC | Jul 13, 14:05 UTC | 6h 50m |
| 2026-07-12 | UAL122 | EWR → LHR | Jul 12, 13:50 UTC | Jul 12, 20:01 UTC | 6h 10m |
| 2026-07-11 | UAL1855 | - | Jul 11, 21:00 UTC | Jul 12, 01:40 UTC | 4h 40m |
| 2026-07-11 | UAL2692 | - | Jul 11, 13:45 UTC | Jul 11, 18:35 UTC | 4h 50m |
| 2026-07-10 | UAL1855 | - | Jul 10, 21:00 UTC | Jul 11, 01:40 UTC | 4h 40m |
| 2026-07-10 | UAL1855 | LAX → EWR | Jul 10, 20:41 UTC | Jul 11, 01:30 UTC | 4h 49m |
| 2026-07-10 | UAL2692 | EWR → LAX | Jul 10, 13:49 UTC | Jul 10, 18:30 UTC | 4h 41m |
| 2026-07-10 | UAL2692 | - | Jul 10, 13:25 UTC | Jul 10, 18:35 UTC | 5h 10m |
| 2026-07-09 | UAL2222 | - | Jul 9, 18:05 UTC | Jul 9, 18:15 UTC | 10m |
| 2026-07-09 | UAL2222 | CPT → EWR | Jul 9, 18:12 UTC | Jul 10, 09:17 UTC | 15h 5m |
| 2026-07-09 | UAL2222 | CPT → EWR | Jul 9, 18:12 UTC | Jul 10, 08:45 UTC | 14h 33m |
| 2026-07-09 | UAL1122 | - | Jul 9, 00:50 UTC | Jul 9, 15:00 UTC | 14h 10m |
| 2026-07-08 | UAL187 | - | Jul 8, 13:15 UTC | Jul 8, 16:55 UTC | 3h 40m |
| 2026-07-08 | UAL187 | SJU → EWR | Jul 8, 13:19 UTC | Jul 8, 16:54 UTC | 3h 35m |
| 2026-07-08 | UAL187 | - | Jul 8, 11:30 UTC | Jul 8, 11:50 UTC | 20m |
| 2026-07-07 | UAL187 | - | Jul 7, 22:50 UTC | Jul 7, 23:15 UTC | 25m |
| 2026-07-07 | UAL187 | JNB → SJU | Jul 7, 23:00 UTC | Jul 8, 11:49 UTC | 12h 49m |
| 2026-07-07 | UAL188 | EWR → JNB | Jul 7, 02:40 UTC | Jul 7, 16:40 UTC | 14h 0m |
| 2026-07-06 | UAL713 | - | Jul 6, 18:45 UTC | Jul 6, 23:25 UTC | 4h 40m |
| 2026-07-05 | UAL61 | - | Jul 5, 01:15 UTC | Jul 5, 14:55 UTC | 13h 40m |
| 2026-07-04 | UAL60 | SFO → MEL | Jul 4, 06:50 UTC | Jul 4, 22:00 UTC | 15h 10m |
| 2026-07-03 | UAL1227 | EWR → SFO | Jul 3, 17:50 UTC | Jul 3, 23:05 UTC | 5h 15m |
| 2026-07-03 | UAL123 | - | Jul 3, 07:10 UTC | Jul 3, 14:30 UTC | 7h 20m |
| 2026-07-02 | UAL122 | EWR → LHR | Jul 2, 14:04 UTC | Jul 2, 20:20 UTC | 6h 16m |
| 2026-07-01 | UAL83 | DEL → EWR | Jul 1, 18:45 UTC | Jul 1, 19:35 UTC | 50m |
| 2026-07-01 | UAL83 | DEL → EWR | Jul 1, 18:53 UTC | Jul 2, 10:16 UTC | 15h 23m |
| 2026-07-01 | UAL82 | - | Jul 1, 02:00 UTC | Jul 1, 16:20 UTC | 14h 20m |
| 2026-06-30 | UAL713 | SFO → EWR | Jun 30, 17:35 UTC | Jun 30, 22:15 UTC | 4h 40m |
| 2026-06-30 | UAL870 | - | Jun 30, 13:00 UTC | Jun 30, 13:40 UTC | 40m |
| 2026-06-30 | UAL870 | - | Jun 30, 00:45 UTC | Jun 30, 01:19 UTC | 35m |
| 2026-06-29 | UAL839 | LAX → SYD | Jun 29, 06:54 UTC | Jun 29, 21:38 UTC | 14h 44m |
| 2026-06-29 | UAL839 | LAX → SYD | Jun 29, 07:05 UTC | Jun 29, 21:14 UTC | 14h 10m |
| 2026-06-28 | UAL199 | PVG → LAX | Jun 28, 13:04 UTC | Jun 28, 23:20 UTC | 10h 15m |
| 2026-06-27 | UAL199 | PVG → LAX | Jun 27, 20:29 UTC | Jun 28, 14:30 UTC | 18h 0m |
| 2026-06-27 | UAL33 | - | Jun 27, 07:59 UTC | Jun 27, 17:29 UTC | 9h 30m |
| 2026-06-26 | UAL7 | - | Jun 26, 15:49 UTC | Jun 27, 04:39 UTC | 12h 50m |
| 2026-06-26 | UAL63 | - | Jun 26, 01:10 UTC | Jun 26, 10:35 UTC | 9h 25m |
| 2026-06-25 | UAL62 | - | Jun 25, 00:05 UTC | Jun 25, 09:29 UTC | 9h 25m |
| 2026-06-24 | UAL6 | - | Jun 24, 08:30 UTC | Jun 24, 19:49 UTC | 11h 20m |
| 2026-06-23 | UAL32 | - | Jun 23, 18:25 UTC | Jun 24, 05:05 UTC | 10h 40m |
| 2026-06-22 | UAL935 | - | Jun 22, 12:40 UTC | Jun 22, 23:05 UTC | 10h 25m |
| 2026-06-22 | UAL935 | LHR → LAX | Jun 22, 12:30 UTC | Jun 22, 23:01 UTC | 10h 31m |
| 2026-06-21 | UAL923 | - | Jun 21, 22:49 UTC | Jun 22, 08:44 UTC | 9h 55m |
| 2026-06-21 | UAL153 | HKG → LAX | Jun 21, 05:15 UTC | Jun 21, 18:25 UTC | 13h 10m |
| 2026-06-21 | UAL153 | HKG → LAX | Jun 21, 02:10 UTC | Jun 21, 02:30 UTC | 20m |
| 2026-06-20 | UAL152 | LAX → HKG | Jun 20, 12:50 UTC | Jun 20, 13:04 UTC | 15m |
| 2026-06-20 | UAL152 | LAX → HKG | Jun 20, 12:49 UTC | Jun 20, 14:51 UTC | 2h 2m |
| 2026-06-19 | UAL152 | LAX → HKG | Jun 19, 20:14 UTC | Jun 19, 21:14 UTC | 1h 0m |
| 2026-06-19 | UAL152 | LAX → HKG | Jun 19, 20:08 UTC | Jun 20, 10:20 UTC | 14h 12m |
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 N45956 page for operator, model, and routing details .