sensors Mode-S transponder
A18D29
ICAO 24-bit transponder address · allocated to United States
Currently assigned to N19986 · BOEING 787-9 Dreamliner · operated by UNITED AIRLINES INC
- Hex
- A18D29
- Octal
- 50306451
- Decimal
- 10,587,433
- Country
- US
- Tail
- N19986
- Type
- B789
- Flights observed
- 210
- Distinct callsigns
- 20
- Country
- US
- Last broadcast
- 1h ago
Last known position
Country allocation
The ICAO 24-bit address A18D29 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 |
|---|---|---|---|
| UAL181 | United Airlines | 11 | 2026-04-15 |
| UAL820 | - | 8 | 2026-06-29 |
| UAL821 | - | 7 | 2026-06-30 |
| UAL153 | - | 7 | 2026-07-12 |
| UAL123 | - | 7 | 2026-06-27 |
| UAL178 | United Airlines | 6 | 2026-04-27 |
| UAL177 | United Airlines | 6 | 2026-04-26 |
| UAL122 | - | 6 | 2026-06-26 |
| UAL839 | - | 5 | 2026-07-14 |
| UAL82 | - | 5 | 2026-06-22 |
| UAL78 | United Airlines | 5 | 2026-05-17 |
| UAL63 | - | 5 | 2026-07-09 |
| UAL182 | United Airlines | 5 | 2026-04-15 |
| UAL152 | - | 5 | 2026-07-11 |
| UAL143 | United Airlines | 5 | 2026-04-30 |
| UAL892 | United Airlines | 4 | 2026-06-03 |
| UAL79 | United Airlines | 4 | 2026-05-16 |
| UAL33 | - | 4 | 2026-07-10 |
| UAL27 | United Airlines | 4 | 2026-04-16 |
| UAL262 | United Airlines | 4 | 2026-04-28 |
Recent flights last 50
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-07-14 | UAL839 | - | Jul 14, 06:55 UTC | Jul 14, 20:15 UTC | 13h 20m |
| 2026-07-13 | UAL935 | - | Jul 13, 12:35 UTC | Jul 13, 22:45 UTC | 10h 10m |
| 2026-07-12 | UAL923 | LAX → LHR | Jul 12, 22:55 UTC | Jul 13, 08:50 UTC | 9h 55m |
| 2026-07-12 | UAL153 | HKG → LAX | Jul 12, 05:08 UTC | Jul 12, 18:35 UTC | 13h 27m |
| 2026-07-12 | UAL153 | - | Jul 12, 05:10 UTC | Jul 12, 18:35 UTC | 13h 25m |
| 2026-07-12 | UAL153 | - | Jul 12, 02:15 UTC | Jul 12, 02:30 UTC | 15m |
| 2026-07-11 | UAL152 | - | Jul 11, 13:35 UTC | Jul 11, 13:45 UTC | 10m |
| 2026-07-10 | UAL152 | LAX → HKG | Jul 10, 20:35 UTC | Jul 11, 11:00 UTC | 14h 25m |
| 2026-07-10 | UAL152 | LAX → HKG | Jul 10, 20:18 UTC | Jul 11, 10:56 UTC | 14h 38m |
| 2026-07-10 | UAL33 | - | Jul 10, 08:25 UTC | Jul 10, 17:55 UTC | 9h 30m |
| 2026-07-10 | UAL33 | NRT → LAX | Jul 10, 08:15 UTC | Jul 10, 17:44 UTC | 9h 29m |
| 2026-07-09 | UAL7 | - | Jul 9, 16:00 UTC | Jul 10, 04:55 UTC | 12h 55m |
| 2026-07-09 | UAL63 | - | Jul 9, 01:05 UTC | Jul 9, 10:50 UTC | 9h 45m |
| 2026-07-08 | UAL62 | - | Jul 8, 00:15 UTC | Jul 8, 09:20 UTC | 9h 5m |
| 2026-07-07 | UAL6 | - | Jul 7, 08:10 UTC | Jul 7, 19:30 UTC | 11h 20m |
| 2026-07-06 | UAL32 | - | Jul 6, 18:05 UTC | Jul 6, 19:05 UTC | 1h 0m |
| 2026-07-06 | UAL32 | LAX → NRT | Jul 6, 18:15 UTC | Jul 7, 04:41 UTC | 10h 26m |
| 2026-07-06 | UAL842 | - | Jul 6, 00:05 UTC | Jul 6, 00:15 UTC | 10m |
| 2026-07-05 | UAL842 | SYD → LAX | Jul 5, 23:51 UTC | Jul 6, 13:09 UTC | 13h 18m |
| 2026-07-05 | UAL839 | - | Jul 5, 06:40 UTC | Jul 5, 07:10 UTC | 30m |
| 2026-07-05 | UAL839 | LAX → SYD | Jul 5, 06:41 UTC | Jul 5, 21:10 UTC | 14h 29m |
| 2026-07-04 | UAL199 | PVG → LAX | Jul 4, 06:20 UTC | Jul 5, 00:00 UTC | 17h 40m |
| 2026-07-03 | UAL198 | - | Jul 3, 20:30 UTC | Jul 4, 15:00 UTC | 18h 30m |
| 2026-07-03 | UAL153 | HKG → LAX | Jul 3, 05:08 UTC | Jul 3, 17:35 UTC | 12h 27m |
| 2026-07-03 | UAL153 | HKG → LAX | Jul 3, 05:00 UTC | Jul 3, 08:15 UTC | 3h 15m |
| 2026-07-03 | UAL153 | HKG → LAX | Jul 3, 02:30 UTC | Jul 3, 02:40 UTC | 10m |
| 2026-07-03 | UAL153 | HKG → LAX | Jul 3, 01:15 UTC | Jul 3, 01:35 UTC | 20m |
| 2026-07-02 | UAL152 | LAX → HKG | Jul 2, 12:49 UTC | Jul 2, 15:05 UTC | 2h 16m |
| 2026-07-01 | UAL152 | LAX → HKG | Jul 1, 20:15 UTC | Jul 2, 10:10 UTC | 13h 55m |
| 2026-06-30 | UAL821 | - | Jun 30, 01:14 UTC | Jun 30, 05:55 UTC | 4h 40m |
| 2026-06-29 | UAL821 | - | Jun 29, 23:34 UTC | Jun 29, 23:54 UTC | 20m |
| 2026-06-29 | UAL821 | - | Jun 29, 14:04 UTC | Jun 29, 15:09 UTC | 1h 5m |
| 2026-06-29 | UAL821 | - | Jun 29, 11:10 UTC | Jun 29, 11:14 UTC | 5m |
| 2026-06-29 | UAL821 | - | Jun 29, 09:05 UTC | Jun 29, 10:24 UTC | 1h 20m |
| 2026-06-29 | UAL820 | - | Jun 29, 01:10 UTC | Jun 29, 02:14 UTC | 1h 5m |
| 2026-06-29 | UAL820 | - | Jun 29, 00:20 UTC | Jun 29, 00:29 UTC | 10m |
| 2026-06-29 | UAL820 | HKG → BKK | Jun 29, 00:01 UTC | Jun 29, 02:30 UTC | 2h 29m |
| 2026-06-28 | UAL820 | - | Jun 28, 07:20 UTC | Jun 28, 08:19 UTC | 1h 0m |
| 2026-06-28 | UAL820 | LAX → HKG | Jun 28, 07:14 UTC | Jun 28, 21:26 UTC | 14h 12m |
| 2026-06-27 | UAL353 | EWR → LAX | Jun 27, 23:00 UTC | Jun 28, 04:10 UTC | 5h 10m |
| 2026-06-27 | UAL123 | - | Jun 27, 06:54 UTC | Jun 27, 13:44 UTC | 6h 50m |
| 2026-06-26 | UAL122 | - | Jun 26, 13:49 UTC | Jun 26, 19:50 UTC | 6h 0m |
| 2026-06-22 | UAL83 | DEL → EWR | Jun 22, 18:30 UTC | Jun 23, 10:35 UTC | 16h 5m |
| 2026-06-22 | UAL82 | - | Jun 22, 01:35 UTC | Jun 22, 15:20 UTC | 13h 45m |
| 2026-06-21 | UAL713 | SFO → EWR | Jun 21, 17:45 UTC | Jun 21, 21:56 UTC | 4h 11m |
| 2026-06-21 | UAL713 | SFO → EWR | Jun 21, 17:35 UTC | Jun 21, 22:04 UTC | 4h 30m |
| 2026-06-21 | UAL806 | ICN → SFO | Jun 21, 02:56 UTC | Jun 21, 13:22 UTC | 10h 26m |
| 2026-06-21 | UAL806 | - | Jun 21, 03:00 UTC | Jun 21, 13:20 UTC | 10h 20m |
| 2026-06-20 | UAL805 | SFO → ICN | Jun 20, 07:45 UTC | Jun 20, 18:56 UTC | 11h 11m |
| 2026-06-20 | UAL805 | - | Jun 20, 07:44 UTC | Jun 20, 18:14 UTC | 10h 30m |
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 N19986 page for operator, model, and routing details .