Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

A2B8FE

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N2749U · BOEING 777-300ER · operated by UNITED AIRLINES INC

Hex
A2B8FE
Octal
50534376
Decimal
10,664,190
Country
US
Tail
N2749U
Type
B77W
No current signal · last broadcast 8h ago
Flights observed
213
Distinct callsigns
20
Country
US
Last broadcast
8h ago

Last known position

Most recent position reported by Mode-S A2B8FE.

Country allocation

The ICAO 24-bit address A2B8FE 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
UAL877 - 17 2026-06-30
UAL858 - 16 2026-07-11
UAL810 - 15 2026-06-29
UAL809 - 14 2026-06-28
UAL857 - 12 2026-07-10
UAL872 - 11 2026-07-06
UAL862 - 11 2026-07-01
UAL838 - 11 2026-07-09
UAL869 - 10 2026-07-11
UAL878 - 9 2026-07-12
UAL871 - 9 2026-07-04
UAL988 United Airlines 7 2026-06-08
UAL837 United Airlines 7 2026-07-01
UAL79 - 7 2026-07-08
UAL42 - 6 2026-06-13
UAL2416 - 5 2026-07-08
UAL989 United Airlines 3 2026-06-09
UAL950 United Airlines 3 2026-06-08
UAL803 United Airlines 3 2026-04-14
UAL1175 United Airlines 3 2026-06-05

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-14 UAL190 - Jul 14, 01:20 UTCJul 14, 01:45 UTC25m
2026-07-13 UAL189 - Jul 13, 08:15 UTCJul 13, 21:20 UTC13h 5m
2026-07-12 UAL878 - Jul 12, 14:50 UTCJul 13, 03:20 UTC12h 30m
2026-07-11 UAL869 SFO → HKG Jul 11, 21:22 UTCJul 12, 10:37 UTC13h 15m
2026-07-11 UAL869 SFO → HKG Jul 11, 21:30 UTCJul 12, 10:40 UTC13h 10m
2026-07-11 UAL858 - Jul 11, 05:05 UTCJul 11, 06:40 UTC1h 35m
2026-07-11 UAL858 PVG → SFO Jul 11, 04:44 UTCJul 11, 15:19 UTC10h 35m
2026-07-10 UAL858 - Jul 10, 07:35 UTCJul 11, 06:40 UTC23h 5m
2026-07-10 UAL857 - Jul 10, 06:25 UTCJul 11, 05:31 UTC23h 6m
2026-07-09 UAL857 SFO → PVG Jul 9, 21:02 UTCJul 10, 09:07 UTC12h 5m
2026-07-09 UAL857 - Jul 9, 21:05 UTCJul 9, 21:30 UTC25m
2026-07-09 UAL838 - Jul 9, 08:30 UTCJul 9, 17:35 UTC9h 5m
2026-07-09 UAL838 NRT → SFO Jul 9, 08:31 UTCJul 9, 17:27 UTC8h 56m
2026-07-08 UAL79 EWR → NRT Jul 8, 16:02 UTCJul 9, 05:02 UTC13h 0m
2026-07-08 UAL79 - Jul 8, 16:00 UTCJul 8, 17:10 UTC1h 10m
2026-07-08 UAL2416 SFO → EWR Jul 8, 07:25 UTCJul 8, 12:00 UTC4h 35m
2026-07-07 UAL878 HKG → SFO Jul 7, 14:51 UTCJul 8, 03:08 UTC12h 17m
2026-07-07 UAL878 - Jul 7, 15:05 UTCJul 8, 03:10 UTC12h 5m
2026-07-06 UAL869 - Jul 6, 21:20 UTCJul 7, 10:45 UTC13h 25m
2026-07-06 UAL872 TPE → SFO Jul 6, 02:43 UTCJul 6, 13:41 UTC10h 58m
2026-07-06 UAL872 - Jul 6, 02:25 UTCJul 6, 13:45 UTC11h 20m
2026-07-04 UAL871 SFO → TPE Jul 4, 22:08 UTCJul 5, 10:25 UTC12h 17m
2026-07-04 UAL871 - Jul 4, 22:00 UTCJul 4, 22:25 UTC25m
2026-07-04 UAL858 PVG → SFO Jul 4, 04:44 UTCJul 4, 15:18 UTC10h 34m
2026-07-03 UAL858 - Jul 3, 07:35 UTCJul 4, 06:55 UTC23h 20m
2026-07-02 UAL857 SFO → PVG Jul 2, 21:01 UTCJul 3, 09:11 UTC12h 10m
2026-07-02 UAL857 - Jul 2, 21:05 UTCJul 3, 08:10 UTC11h 5m
2026-07-02 UAL838 NRT → SFO Jul 2, 08:41 UTCJul 2, 17:56 UTC9h 15m
2026-07-02 UAL838 - Jul 2, 08:40 UTCJul 2, 18:00 UTC9h 20m
2026-07-01 UAL837 SFO → NRT Jul 1, 20:10 UTCJul 2, 06:20 UTC10h 10m
2026-07-01 UAL862 HKG → SFO Jul 1, 04:10 UTCJul 1, 16:25 UTC12h 15m
2026-06-30 UAL877 SFO → HKG Jun 30, 07:40 UTCJun 30, 20:54 UTC13h 14m
2026-06-30 UAL877 - Jun 30, 07:45 UTCJun 30, 08:05 UTC20m
2026-06-29 UAL810 - Jun 29, 13:44 UTCJun 30, 02:10 UTC12h 25m
2026-06-28 UAL809 - Jun 28, 21:50 UTCJun 28, 22:15 UTC25m
2026-06-28 UAL809 SFO → MNL Jun 28, 21:43 UTCJun 29, 10:39 UTC12h 56m
2026-06-28 UAL838 - Jun 28, 08:59 UTCJun 28, 09:30 UTC30m
2026-06-28 UAL838 NRT → SFO Jun 28, 08:54 UTCJun 28, 17:35 UTC8h 41m
2026-06-27 UAL837 SFO → NRT Jun 27, 19:59 UTCJun 28, 06:15 UTC10h 15m
2026-06-27 UAL837 SFO → NRT Jun 27, 19:52 UTCJun 28, 06:05 UTC10h 13m
2026-06-27 UAL872 - Jun 27, 02:35 UTCJun 27, 02:45 UTC10m
2026-06-27 UAL872 TPE → SFO Jun 27, 02:33 UTCJun 27, 14:03 UTC11h 30m
2026-06-25 UAL871 SFO → TPE Jun 25, 22:08 UTCJun 26, 10:44 UTC12h 36m
2026-06-25 UAL871 - Jun 25, 22:20 UTCJun 26, 10:44 UTC12h 25m
2026-06-25 UAL858 - Jun 25, 05:39 UTCJun 25, 15:04 UTC9h 25m
2026-06-24 UAL858 - Jun 24, 07:34 UTCJun 25, 06:55 UTC23h 20m
2026-06-23 UAL857 - Jun 23, 20:59 UTCJun 24, 07:59 UTC11h 0m
2026-06-23 UAL862 HKG → SFO Jun 23, 04:11 UTCJun 23, 16:29 UTC12h 18m
2026-06-23 UAL862 - Jun 23, 04:09 UTCJun 23, 16:35 UTC12h 25m
2026-06-22 UAL877 SFO → HKG Jun 22, 09:16 UTCJun 22, 22:24 UTC13h 8m

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 N2749U page for operator, model, and routing details .

Mode-S A2B8FE frequently asked

What is Mode-S code A2B8FE?
A2B8FE is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N2749U.
Where is Mode-S A2B8FE registered?
Mode-S code A2B8FE is allocated to United States (US). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is A2B8FE broadcasting right now?
No active broadcast right now. Last signal was 8h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A2B8FE, octal 50534376, decimal 10,664,190.
What flights does A2B8FE operate?
Mode-S A2B8FE has broadcast 20 distinct callsigns, including UAL877, UAL858, UAL810, UAL809, UAL857.