Apparatus

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sensors Mode-S transponder

A1B535

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N209UA · BOEING 777-200 · operated by UNITED AIRLINES INC

Hex
A1B535
Octal
50332465
Decimal
10,597,685
Country
US
Tail
N209UA
Type
B772
Broadcasting now · callsign UAL44 · 39,000 ft
Flights observed
167
Distinct callsigns
20
Country
US
Last broadcast
5m ago

Current position

A1B535 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A1B535 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
UAL59 - 11 2026-07-08
UAL35 - 9 2026-07-04
UAL34 - 8 2026-07-05
UAL852 - 7 2026-07-13
UAL853 - 6 2026-07-12
UAL984 - 5 2026-06-30
UAL97 - 5 2026-07-10
UAL969 United Airlines 5 2026-06-08
UAL968 United Airlines 5 2026-06-07
UAL819 United Airlines 5 2026-06-01
UAL58 - 5 2026-07-07
UAL927 - 4 2026-07-11
UAL926 - 4 2026-07-11
UAL803 United Airlines 4 2026-06-25
UAL57 United Airlines 4 2026-06-29
UAL44 - 4 2026-07-13
UAL195 United Airlines 4 2026-06-20
UAL96 - 3 2026-07-09
UAL933 - 3 2026-06-24
UAL932 - 3 2026-06-24

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-13 UAL44 SFO → ZRH Jul 13, 21:48 UTCJul 14, 08:18 UTC10h 30m
2026-07-13 UAL44 - Jul 13, 22:05 UTCJul 14, 00:15 UTC2h 10m
2026-07-13 UAL852 - Jul 13, 07:05 UTCJul 13, 09:15 UTC2h 10m
2026-07-13 UAL852 TPE → SFO Jul 13, 06:51 UTCJul 13, 18:39 UTC11h 48m
2026-07-13 UAL852 TPE → SFO Jul 13, 06:51 UTCJul 13, 18:43 UTC11h 52m
2026-07-12 UAL853 SFO → TPE Jul 12, 07:41 UTCJul 12, 19:43 UTC12h 2m
2026-07-12 UAL853 - Jul 12, 07:35 UTCJul 12, 08:01 UTC25m
2026-07-11 UAL927 - Jul 11, 16:00 UTCJul 12, 03:15 UTC11h 15m
2026-07-11 UAL927 FRA → SFO Jul 11, 15:51 UTCJul 12, 03:24 UTC11h 33m
2026-07-11 UAL926 SFO → FRA Jul 11, 02:44 UTCJul 11, 12:36 UTC9h 52m
2026-07-11 UAL926 - Jul 11, 02:30 UTCJul 11, 11:15 UTC8h 45m
2026-07-10 UAL97 BNE → SFO Jul 10, 07:18 UTCJul 10, 19:38 UTC12h 20m
2026-07-10 UAL97 BNE → SFO Jul 10, 07:18 UTCJul 10, 19:37 UTC12h 19m
2026-07-10 UAL97 - Jul 10, 07:20 UTCJul 10, 07:55 UTC35m
2026-07-09 UAL96 SFO → BNE Jul 9, 15:35 UTCJul 10, 05:15 UTC13h 40m
2026-07-08 UAL59 - Jul 8, 11:20 UTCJul 8, 13:15 UTC1h 55m
2026-07-08 UAL59 FRA → SFO Jul 8, 11:24 UTCJul 8, 22:19 UTC10h 55m
2026-07-08 UAL59 FRA → SFO Jul 8, 11:24 UTCJul 8, 22:19 UTC10h 55m
2026-07-07 UAL58 SFO → FRA Jul 7, 21:45 UTCJul 8, 07:50 UTC10h 5m
2026-07-06 UAL59 - Jul 6, 11:25 UTCJul 6, 13:20 UTC1h 55m
2026-07-06 UAL59 FRA → SFO Jul 6, 11:29 UTCJul 6, 22:19 UTC10h 50m
2026-07-05 UAL58 SFO → FRA Jul 5, 22:10 UTCJul 6, 08:15 UTC10h 5m
2026-07-05 UAL34 - Jul 5, 08:10 UTCJul 5, 17:50 UTC9h 40m
2026-07-04 UAL35 SFO → KIX Jul 4, 18:35 UTCJul 5, 05:15 UTC10h 40m
2026-07-03 UAL889 PEK → SFO Jul 3, 21:00 UTCJul 4, 07:15 UTC10h 15m
2026-07-03 UAL889 PEK → SFO Jul 3, 19:41 UTCJul 4, 07:17 UTC11h 36m
2026-07-03 UAL888 SFO → PEK Jul 3, 04:40 UTCJul 3, 16:20 UTC11h 40m
2026-07-01 UAL45 ZRH → SFO Jul 1, 12:37 UTCJul 2, 00:02 UTC11h 25m
2026-07-01 UAL45 - Jul 1, 12:50 UTCJul 2, 00:05 UTC11h 15m
2026-06-30 UAL44 SFO → ZRH Jun 30, 22:10 UTCJul 1, 08:15 UTC10h 5m
2026-06-30 UAL984 - Jun 30, 07:45 UTCJun 30, 09:05 UTC1h 20m
2026-06-30 UAL984 CDG → SFO Jun 30, 07:44 UTCJun 30, 18:06 UTC10h 22m
2026-06-30 UAL984 CDG → SFO Jun 30, 07:44 UTCJun 30, 17:58 UTC10h 14m
2026-06-29 UAL57 EWR → CDG Jun 29, 22:15 UTCJun 30, 04:50 UTC6h 36m
2026-06-28 UAL366 SFO → EWR Jun 28, 21:10 UTCJun 29, 01:50 UTC4h 40m
2026-06-28 UAL1593 - Jun 28, 13:49 UTCJun 28, 19:09 UTC5h 20m
2026-06-28 UAL148 - Jun 28, 00:39 UTCJun 28, 09:39 UTC9h 0m
2026-06-27 UAL149 - Jun 27, 10:14 UTCJun 27, 10:29 UTC15m
2026-06-27 UAL149 - Jun 27, 01:09 UTCJun 27, 01:39 UTC30m
2026-06-27 UAL149 EWR → GRU Jun 27, 01:01 UTCJun 27, 10:35 UTC9h 34m
2026-06-26 UAL130 HND → EWR Jun 26, 09:14 UTCJun 26, 21:45 UTC12h 30m
2026-06-25 UAL803 IAD → HND Jun 25, 17:20 UTCJun 26, 00:39 UTC7h 20m
2026-06-25 UAL803 IAD → HND Jun 25, 17:10 UTCJun 26, 06:47 UTC13h 37m
2026-06-24 UAL933 FRA → IAD Jun 24, 15:49 UTCJun 25, 00:05 UTC8h 15m
2026-06-24 UAL933 FRA → IAD Jun 24, 15:31 UTCJun 25, 00:03 UTC8h 32m
2026-06-24 UAL932 - Jun 24, 04:59 UTCJun 24, 10:19 UTC5h 20m
2026-06-24 UAL932 - Jun 24, 03:24 UTCJun 24, 04:55 UTC1h 30m
2026-06-24 UAL932 IAD → FRA Jun 24, 02:58 UTCJun 24, 10:07 UTC7h 9m
2026-06-23 UAL914 CDG → IAD Jun 23, 21:10 UTCJun 23, 21:45 UTC35m
2026-06-23 UAL914 CDG → IAD Jun 23, 11:35 UTCJun 23, 12:55 UTC1h 20m

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 N209UA page for operator, model, and routing details .

Mode-S A1B535 frequently asked

What is Mode-S code A1B535?
A1B535 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N209UA.
Where is Mode-S A1B535 registered?
Mode-S code A1B535 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 A1B535 broadcasting right now?
Yes. Mode-S A1B535 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A1B535, octal 50332465, decimal 10,597,685.
What flights does A1B535 operate?
Mode-S A1B535 has broadcast 20 distinct callsigns, including UAL59, UAL35, UAL34, UAL852, UAL853.