sensors Mode-S transponder
A2CB13
ICAO 24-bit transponder address · allocated to United States
Currently assigned to N27958 · BOEING 787-9 Dreamliner · operated by UNITED AIRLINES INC
- Hex
- A2CB13
- Octal
- 50545423
- Decimal
- 10,668,819
- Country
- US
- Tail
- N27958
- Type
- B789
- Flights observed
- 90
- Distinct callsigns
- 20
- Country
- US
- Last broadcast
- 1h ago
Last known position
Country allocation
The ICAO 24-bit address A2CB13 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 |
|---|---|---|---|
| UAL60 | United Airlines | 9 | 2026-05-23 |
| UAL61 | United Airlines | 8 | 2026-05-24 |
| UAL2 | United Airlines | 8 | 2026-04-17 |
| UAL1 | United Airlines | 8 | 2026-05-14 |
| UAL1757 | United Airlines | 6 | 2026-05-29 |
| UAL3964 | United Airlines | 5 | 2026-05-17 |
| UAL1849 | United Airlines | 5 | 2026-05-29 |
| UAL806 | United Airlines | 4 | 2026-05-27 |
| UAL29 | United Airlines | 4 | 2026-05-25 |
| UAL28 | United Airlines | 4 | 2026-05-25 |
| UAL821 | United Airlines | 3 | 2026-05-08 |
| UAL820 | United Airlines | 3 | 2026-05-08 |
| UAL805 | United Airlines | 3 | 2026-05-26 |
| UAL863 | United Airlines | 2 | 2026-05-03 |
| UAL122 | United Airlines | 2 | 2026-05-12 |
| UAL1011 | United Airlines | 2 | 2026-05-01 |
| UAL99 | United Airlines | 1 | 2026-05-09 |
| UAL98 | United Airlines | 1 | 2026-05-09 |
| UAL893 | United Airlines | 1 | 2026-05-18 |
| UAL892 | United Airlines | 1 | 2026-05-19 |
Recent flights last 50
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-05-29 | UAL1757 | PIT → DEN | May 29, 22:50 UTC | May 30, 03:55 UTC | 5h 5m |
| 2026-05-29 | UAL1849 | MCO → EWR | May 29, 15:55 UTC | May 29, 20:25 UTC | 4h 30m |
| 2026-05-29 | UAL1757 | PIT → DEN | May 29, 00:05 UTC | May 29, 05:05 UTC | 5h 0m |
| 2026-05-28 | UAL1849 | MCO → EWR | May 28, 15:45 UTC | May 28, 20:15 UTC | 4h 30m |
| 2026-05-27 | UAL806 | ICN → SFO | May 27, 02:56 UTC | May 27, 13:05 UTC | 10h 9m |
| 2026-05-27 | UAL806 | ICN → SFO | May 27, 02:44 UTC | May 27, 13:10 UTC | 10h 26m |
| 2026-05-26 | UAL805 | SFO → ICN | May 26, 07:45 UTC | May 26, 19:45 UTC | 12h 0m |
| 2026-05-25 | UAL28 | SIN → SFO | May 25, 15:30 UTC | May 26, 04:20 UTC | 12h 49m |
| 2026-05-25 | UAL29 | SFO → SIN | May 25, 10:20 UTC | May 25, 10:45 UTC | 25m |
| 2026-05-24 | UAL29 | SFO → SIN | May 24, 18:55 UTC | May 25, 08:05 UTC | 13h 10m |
| 2026-05-24 | UAL61 | BRU → EWR | May 24, 01:20 UTC | May 24, 15:05 UTC | 13h 45m |
| 2026-05-23 | UAL60 | SFO → MEL | May 23, 07:20 UTC | May 23, 22:19 UTC | 14h 59m |
| 2026-05-23 | UAL60 | SFO → MEL | May 23, 07:30 UTC | May 23, 12:05 UTC | 4h 35m |
| 2026-05-22 | UAL28 | SIN → SFO | May 22, 16:10 UTC | May 23, 04:25 UTC | 12h 15m |
| 2026-05-21 | UAL29 | SFO → SIN | May 21, 18:50 UTC | May 22, 08:00 UTC | 13h 10m |
| 2026-05-21 | UAL61 | BRU → EWR | May 21, 01:09 UTC | May 21, 14:35 UTC | 13h 26m |
| 2026-05-21 | UAL61 | BRU → EWR | May 21, 01:05 UTC | May 21, 14:30 UTC | 13h 25m |
| 2026-05-20 | UAL60 | SFO → MEL | May 20, 07:20 UTC | May 20, 22:30 UTC | 15h 10m |
| 2026-05-19 | UAL892 | ICN → SFO | May 19, 08:20 UTC | May 19, 18:10 UTC | 9h 50m |
| 2026-05-18 | UAL893 | SFO → ICN | May 18, 18:25 UTC | May 19, 06:25 UTC | 11h 59m |
| 2026-05-18 | UAL61 | BRU → EWR | May 18, 01:20 UTC | May 18, 14:50 UTC | 13h 30m |
| 2026-05-17 | UAL60 | SFO → MEL | May 17, 07:10 UTC | May 17, 22:40 UTC | 15h 30m |
| 2026-05-17 | UAL3964 | SIN → HNL | May 17, 03:40 UTC | May 17, 04:15 UTC | 35m |
| 2026-05-16 | UAL3964 | SIN → HNL | May 16, 23:46 UTC | May 17, 04:06 UTC | 4h 20m |
| 2026-05-16 | UAL3964 | SIN → HNL | May 16, 23:35 UTC | May 16, 23:45 UTC | 10m |
| 2026-05-16 | UAL3964 | SIN → HNL | May 16, 21:05 UTC | May 16, 21:15 UTC | 10m |
| 2026-05-16 | UAL3964 | SIN → HNL | May 16, 11:51 UTC | May 16, 12:31 UTC | 40m |
| 2026-05-14 | UAL1 | SFO → SIN | May 14, 06:25 UTC | May 14, 22:52 UTC | 16h 27m |
| 2026-05-14 | UAL1 | SFO → SIN | May 14, 06:50 UTC | May 14, 07:15 UTC | 25m |
| 2026-05-13 | UAL1227 | PHX → IAD | May 13, 17:50 UTC | May 13, 23:30 UTC | 5h 40m |
| 2026-05-13 | UAL123 | ANC → ORD | May 13, 06:55 UTC | May 13, 14:00 UTC | 7h 5m |
| 2026-05-12 | UAL122 | IAD → LHR | May 12, 14:09 UTC | May 12, 20:22 UTC | 6h 13m |
| 2026-05-12 | UAL122 | IAD → LHR | May 12, 14:20 UTC | May 12, 15:40 UTC | 1h 20m |
| 2026-05-11 | UAL1855 | ORD → BOS | May 11, 20:35 UTC | May 11, 22:35 UTC | 1h 59m |
| 2026-05-11 | UAL33 | NRT → LAX | May 11, 07:55 UTC | May 11, 17:20 UTC | 9h 26m |
| 2026-05-10 | UAL32 | LAX → NRT | May 10, 17:49 UTC | May 11, 04:35 UTC | 10h 45m |
| 2026-05-09 | UAL99 | MEL → LAX | May 9, 23:44 UTC | May 10, 13:30 UTC | 13h 45m |
| 2026-05-09 | UAL98 | LAX → MEL | May 9, 06:15 UTC | May 9, 21:34 UTC | 15h 20m |
| 2026-05-08 | UAL821 | SFO → MEX | May 8, 14:00 UTC | May 9, 02:30 UTC | 12h 30m |
| 2026-05-08 | UAL821 | SFO → MEX | May 8, 11:09 UTC | May 8, 11:25 UTC | 15m |
| 2026-05-08 | UAL821 | SFO → MEX | May 8, 08:59 UTC | May 8, 09:34 UTC | 35m |
| 2026-05-08 | UAL820 | MEX → SFO | May 8, 00:01 UTC | May 8, 02:25 UTC | 2h 24m |
| 2026-05-08 | UAL820 | MEX → SFO | May 8, 00:05 UTC | May 8, 00:20 UTC | 15m |
| 2026-05-07 | UAL820 | MEX → SFO | May 7, 06:25 UTC | May 7, 20:55 UTC | 14h 30m |
| 2026-05-05 | UAL3925 | EWR → SFO | May 5, 05:40 UTC | May 5, 18:20 UTC | 12h 40m |
| 2026-05-03 | UAL863 | SFO → SYD | May 3, 06:15 UTC | May 3, 20:40 UTC | 14h 25m |
| 2026-05-02 | UAL1757 | PIT → DEN | May 2, 22:10 UTC | May 3, 03:10 UTC | 5h 0m |
| 2026-05-01 | UAL2023 | BOS → ORD | May 1, 18:40 UTC | May 2, 10:10 UTC | 15h 30m |
| 2026-05-01 | UAL1011 | MCI → SFO | May 1, 13:05 UTC | May 1, 13:30 UTC | 25m |
| 2026-04-30 | UAL1011 | MCI → SFO | Apr 30, 23:35 UTC | May 1, 00:10 UTC | 35m |
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 N27958 page for operator, model, and routing details .