Apparatus

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sensors Mode-S transponder

A1C82A

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N2138U · BOEING 777-300ER · operated by UNITED AIRLINES INC

Hex
A1C82A
Octal
50344052
Decimal
10,602,538
Country
US
Tail
N2138U
Type
B77W
Broadcasting now · callsign UAL2416 · 33,000 ft
Flights observed
241
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 22:30 UTC

Current position

A1C82A is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A1C82A 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
UAL862 United Airlines 18 2026-07-23
UAL857 United Airlines 18 2026-07-24
UAL877 United Airlines 13 2026-07-22
UAL858 United Airlines 13 2026-07-25
UAL41 - 13 2026-07-13
UAL878 United Airlines 12 2026-07-21
UAL869 United Airlines 11 2026-07-20
UAL40 - 11 2026-07-12
UAL190 - 11 2026-07-05
UAL838 United Airlines 9 2026-07-26
UAL42 - 9 2026-07-08
UAL950 - 7 2026-07-08
UAL837 United Airlines 7 2026-07-25
UAL43 - 7 2026-07-11
UAL189 - 7 2026-07-04
UAL1149 United Airlines 7 2026-05-14
UAL989 - 6 2026-07-11
UAL988 - 6 2026-07-10
UAL1175 - 6 2026-07-05
UAL951 - 5 2026-07-09

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL871 SFO → TPE Jul 26, 22:20 UTCJul 26, 22:30 UTC10m
2026-07-26 UAL838 NRT → SFO Jul 26, 08:25 UTCJul 26, 09:00 UTC35m
2026-07-26 UAL838 NRT → SFO Jul 26, 08:31 UTCJul 26, 17:31 UTC9h 0m
2026-07-26 UAL838 NRT → SFO Jul 26, 08:31 UTCJul 26, 17:29 UTC8h 58m
2026-07-25 UAL837 SFO → NRT Jul 25, 19:52 UTCJul 26, 05:35 UTC9h 43m
2026-07-25 UAL837 SFO → NRT Jul 25, 19:50 UTCJul 26, 05:40 UTC9h 50m
2026-07-25 UAL858 ICN → SFO Jul 25, 05:35 UTCJul 25, 15:45 UTC10h 10m
2026-07-24 UAL857 ICN → PVG Jul 24, 06:35 UTCJul 25, 06:30 UTC23h 55m
2026-07-23 UAL857 ICN → PVG Jul 23, 21:05 UTCJul 24, 07:45 UTC10h 40m
2026-07-23 UAL862 HKG → SFO Jul 23, 16:55 UTCJul 23, 17:00 UTC5m
2026-07-23 UAL862 HKG → SFO Jul 23, 04:11 UTCJul 23, 16:38 UTC12h 27m
2026-07-23 UAL862 HKG → SFO Jul 23, 04:10 UTCJul 23, 08:00 UTC3h 50m
2026-07-22 UAL877 SFO → HKG Jul 22, 07:21 UTCJul 22, 20:16 UTC12h 55m
2026-07-21 UAL878 HKG → SFO Jul 21, 14:51 UTCJul 22, 03:16 UTC12h 25m
2026-07-21 UAL878 HKG → SFO Jul 21, 14:51 UTCJul 22, 03:02 UTC12h 11m
2026-07-21 UAL878 HKG → SFO Jul 21, 14:45 UTCJul 21, 15:55 UTC1h 10m
2026-07-20 UAL869 SFO → HKG Jul 20, 21:22 UTCJul 21, 10:37 UTC13h 15m
2026-07-20 UAL869 SFO → HKG Jul 20, 21:40 UTCJul 21, 10:30 UTC12h 49m
2026-07-20 UAL858 ICN → SFO Jul 20, 05:15 UTCJul 20, 15:40 UTC10h 25m
2026-07-19 UAL858 ICN → SFO Jul 19, 06:35 UTCJul 20, 06:30 UTC23h 55m
2026-07-18 UAL857 SFO → PVG Jul 18, 21:07 UTCJul 19, 08:36 UTC11h 29m
2026-07-18 UAL857 - Jul 18, 21:00 UTCJul 19, 07:45 UTC10h 45m
2026-07-18 UAL862 HKG → SFO Jul 18, 04:11 UTCJul 18, 16:48 UTC12h 37m
2026-07-18 UAL862 HKG → SFO Jul 18, 04:11 UTCJul 18, 16:45 UTC12h 34m
2026-07-18 UAL862 HKG → SFO Jul 18, 04:00 UTCJul 18, 16:50 UTC12h 50m
2026-07-17 UAL877 - Jul 17, 20:29 UTCJul 17, 20:40 UTC10m
2026-07-17 UAL877 SFO → HKG Jul 17, 07:21 UTCJul 17, 20:14 UTC12h 53m
2026-07-17 UAL877 - Jul 17, 07:25 UTCJul 17, 17:50 UTC10h 25m
2026-07-14 UAL1960 - Jul 14, 17:25 UTCJul 14, 22:10 UTC4h 45m
2026-07-13 UAL41 - Jul 13, 09:30 UTCJul 13, 10:30 UTC1h 0m
2026-07-13 UAL41 FCO → EWR Jul 13, 09:27 UTCJul 13, 18:11 UTC8h 44m
2026-07-13 UAL41 FCO → EWR Jul 13, 09:27 UTCJul 13, 18:13 UTC8h 46m
2026-07-12 UAL40 EWR → FCO Jul 12, 22:18 UTCJul 13, 05:58 UTC7h 40m
2026-07-12 UAL40 - Jul 12, 22:15 UTCJul 13, 06:01 UTC7h 45m
2026-07-12 UAL41 - Jul 12, 09:45 UTCJul 12, 18:15 UTC8h 30m
2026-07-11 UAL40 EWR → FCO Jul 11, 21:48 UTCJul 12, 05:33 UTC7h 45m
2026-07-11 UAL40 - Jul 11, 21:55 UTCJul 11, 22:30 UTC35m
2026-07-11 UAL43 FRA → EWR Jul 11, 10:51 UTCJul 11, 18:36 UTC7h 45m
2026-07-11 UAL43 FRA → EWR Jul 11, 10:45 UTCJul 11, 18:30 UTC7h 45m
2026-07-11 UAL989 IAD → FRA Jul 11, 01:15 UTCJul 11, 08:20 UTC7h 5m
2026-07-10 UAL988 - Jul 10, 12:50 UTCJul 10, 21:15 UTC8h 25m
2026-07-10 UAL989 IAD → FRA Jul 10, 02:50 UTCJul 10, 10:00 UTC7h 10m
2026-07-09 UAL951 BRU → IAD Jul 9, 10:25 UTCJul 9, 18:25 UTC8h 0m
2026-07-08 UAL950 IAD → BRU Jul 8, 22:28 UTCJul 9, 05:26 UTC6h 58m
2026-07-08 UAL950 - Jul 8, 22:30 UTCJul 9, 04:30 UTC6h 0m
2026-07-08 UAL988 - Jul 8, 10:45 UTCJul 8, 12:30 UTC1h 45m
2026-07-08 UAL988 FRA → IAD Jul 8, 10:39 UTCJul 8, 18:35 UTC7h 56m
2026-07-08 UAL42 EWR → FRA Jul 8, 00:20 UTCJul 8, 07:14 UTC6h 54m
2026-07-08 UAL42 - Jul 8, 00:10 UTCJul 8, 01:45 UTC1h 35m
2026-07-07 UAL435 SFO → EWR Jul 7, 15:35 UTCJul 7, 20:20 UTC4h 45m

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 N2138U page for operator, model, and routing details .

Mode-S A1C82A frequently asked

What is Mode-S code A1C82A?
A1C82A is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N2138U.
Where is Mode-S A1C82A registered?
Mode-S code A1C82A 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 A1C82A broadcasting right now?
Yes. Mode-S A1C82A is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A1C82A, octal 50344052, decimal 10,602,538.
What flights does A1C82A operate?
Mode-S A1C82A has broadcast 20 distinct callsigns, including UAL862, UAL857, UAL877, UAL858, UAL41.