Apparatus

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sensors Mode-S transponder

AAC8A4

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N794UA · BOEING 777-200 · operated by UNITED AIRLINES INC

Hex
AAC8A4
Octal
52544244
Decimal
11,192,484
Country
US
Tail
N794UA
Type
B772
No current signal · last broadcast 18h ago
Flights observed
205
Distinct callsigns
20
Country
US
Last broadcast
18h ago

Last known position

Most recent position reported by Mode-S AAC8A4.

Country allocation

The ICAO 24-bit address AAC8A4 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
UAL852 - 11 2026-06-25
UAL949 United Airlines 9 2026-06-12
UAL853 - 9 2026-06-24
UAL46 United Airlines 9 2026-06-10
UAL673 - 8 2026-07-13
UAL35 - 8 2026-06-14
UAL819 - 7 2026-07-09
UAL672 - 7 2026-07-13
UAL34 - 7 2026-06-15
UAL195 - 7 2026-07-12
UAL102 - 7 2026-07-11
UAL990 - 6 2026-07-01
UAL968 - 6 2026-06-15
UAL818 - 6 2026-07-10
UAL47 United Airlines 6 2026-06-11
UAL160 - 6 2026-07-08
UAL969 - 5 2026-06-16
UAL939 United Airlines 5 2026-04-18
UAL914 United Airlines 5 2026-07-02
UAL5 United Airlines 5 2026-06-12

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-13 UAL673 - Jul 13, 14:35 UTCJul 14, 02:20 UTC11h 45m
2026-07-13 UAL672 SFO → BCN Jul 13, 01:15 UTCJul 13, 12:00 UTC10h 45m
2026-07-12 UAL195 - Jul 12, 10:20 UTCJul 12, 21:50 UTC11h 30m
2026-07-11 UAL102 - Jul 11, 21:55 UTCJul 12, 01:55 UTC4h 0m
2026-07-11 UAL102 IAH → MUC Jul 11, 22:02 UTCJul 12, 07:53 UTC9h 51m
2026-07-10 UAL818 - Jul 10, 00:15 UTCJul 10, 10:05 UTC9h 50m
2026-07-09 UAL819 - Jul 9, 01:55 UTCJul 9, 07:30 UTC5h 35m
2026-07-09 UAL819 IAH → EZE Jul 9, 02:06 UTCJul 9, 11:07 UTC9h 1m
2026-07-08 UAL160 - Jul 8, 10:30 UTCJul 8, 21:05 UTC10h 35m
2026-07-07 UAL194 SFO → MUC Jul 7, 21:35 UTCJul 8, 07:55 UTC10h 20m
2026-07-06 UAL506 - Jul 6, 14:00 UTCJul 7, 02:15 UTC12h 15m
2026-07-06 UAL507 - Jul 6, 00:30 UTCJul 6, 09:00 UTC8h 30m
2026-07-06 UAL507 SFO → FCO Jul 6, 00:19 UTCJul 6, 11:41 UTC11h 22m
2026-07-05 UAL195 MUC → SFO Jul 5, 10:10 UTCJul 5, 16:00 UTC5h 50m
2026-07-05 UAL195 MUC → SFO Jul 5, 10:10 UTCJul 5, 21:31 UTC11h 21m
2026-07-05 UAL195 MUC → SFO Jul 5, 10:10 UTCJul 5, 21:34 UTC11h 24m
2026-07-04 UAL102 - Jul 4, 22:15 UTCJul 5, 07:00 UTC8h 45m
2026-07-04 UAL102 IAH → MUC Jul 4, 22:22 UTCJul 5, 07:41 UTC9h 19m
2026-07-04 UAL879 - Jul 4, 09:30 UTCJul 4, 19:00 UTC9h 30m
2026-07-04 UAL879 LHR → IAH Jul 4, 09:25 UTCJul 4, 19:11 UTC9h 46m
2026-07-03 UAL880 IAH → LHR Jul 3, 22:35 UTCJul 4, 07:15 UTC8h 40m
2026-07-03 UAL880 IAH → LHR Jul 3, 22:26 UTCJul 4, 07:11 UTC8h 45m
2026-07-03 UAL879 - Jul 3, 09:25 UTCJul 3, 18:55 UTC9h 30m
2026-07-02 UAL918 IAD → LHR Jul 2, 23:36 UTCJul 3, 05:46 UTC6h 10m
2026-07-02 UAL918 IAD → LHR Jul 2, 23:25 UTCJul 3, 05:55 UTC6h 30m
2026-07-02 UAL914 CDG → IAD Jul 2, 10:40 UTCJul 2, 18:30 UTC7h 50m
2026-07-01 UAL990 - Jul 1, 22:30 UTCJul 2, 08:15 UTC9h 45m
2026-07-01 UAL1593 - Jul 1, 13:50 UTCJul 1, 18:55 UTC5h 5m
2026-07-01 UAL1141 SFO → EWR Jul 1, 06:15 UTCJul 1, 11:00 UTC4h 45m
2026-06-29 UAL673 BCN → SFO Jun 29, 14:31 UTCJun 30, 01:40 UTC11h 9m
2026-06-29 UAL673 BCN → SFO Jun 29, 14:31 UTCJun 30, 01:36 UTC11h 5m
2026-06-29 UAL673 - Jun 29, 14:25 UTCJun 29, 16:44 UTC2h 20m
2026-06-29 UAL672 SFO → BCN Jun 29, 01:14 UTCJun 29, 11:45 UTC10h 30m
2026-06-28 UAL59 FRA → SFO Jun 28, 12:44 UTCJun 28, 22:08 UTC9h 24m
2026-06-28 UAL59 - Jun 28, 11:59 UTCJun 28, 18:14 UTC6h 15m
2026-06-27 UAL58 - Jun 27, 21:15 UTCJun 28, 07:34 UTC10h 20m
2026-06-26 UAL673 - Jun 26, 14:50 UTCJun 26, 18:20 UTC3h 30m
2026-06-26 UAL673 BCN → SFO Jun 26, 14:31 UTCJun 27, 02:13 UTC11h 42m
2026-06-26 UAL672 SFO → BCN Jun 26, 01:29 UTCJun 26, 12:14 UTC10h 45m
2026-06-26 UAL672 SFO → BCN Jun 26, 01:24 UTCJun 26, 12:24 UTC11h 0m
2026-06-25 UAL852 - Jun 25, 17:20 UTCJun 25, 18:00 UTC40m
2026-06-25 UAL852 TPE → SFO Jun 25, 06:51 UTCJun 25, 17:55 UTC11h 4m
2026-06-25 UAL852 - Jun 25, 06:40 UTCJun 25, 07:00 UTC20m
2026-06-24 UAL853 SFO → TPE Jun 24, 07:30 UTCJun 24, 20:09 UTC12h 40m
2026-06-23 UAL889 PEK → SFO Jun 23, 10:29 UTCJun 23, 10:59 UTC30m
2026-06-23 UAL889 PEK → SFO Jun 23, 09:40 UTCJun 23, 09:49 UTC10m
2026-06-23 UAL889 PEK → SFO Jun 23, 09:51 UTCJun 23, 20:38 UTC10h 47m
2026-06-23 UAL889 PEK → SFO Jun 23, 09:51 UTCJun 23, 20:32 UTC10h 41m
2026-06-22 UAL888 SFO → PEK Jun 22, 18:15 UTCJun 23, 07:13 UTC12h 58m
2026-06-22 UAL888 SFO → PEK Jun 22, 18:24 UTCJun 23, 06:04 UTC11h 40m

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 N794UA page for operator, model, and routing details .

Mode-S AAC8A4 frequently asked

What is Mode-S code AAC8A4?
AAC8A4 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N794UA.
Where is Mode-S AAC8A4 registered?
Mode-S code AAC8A4 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 AAC8A4 broadcasting right now?
No active broadcast right now. Last signal was 18h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AAC8A4, octal 52544244, decimal 11,192,484.
What flights does AAC8A4 operate?
Mode-S AAC8A4 has broadcast 20 distinct callsigns, including UAL852, UAL949, UAL853, UAL46, UAL673.