Apparatus

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sensors Mode-S transponder

A87223

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N643UA · BOEING 767-300 · operated by UNITED AIRLINES INC

Hex
A87223
Octal
52071043
Decimal
11,039,267
Country
US
Tail
N643UA
Type
B763
Broadcasting now · callsign UAL21 · 32,025 ft
Flights observed
185
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 11:15 UTC

Current position

A87223 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A87223 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
UAL855 - 19 2026-07-14
UAL854 - 18 2026-07-13
UAL20 - 17 2026-07-14
UAL128 - 16 2026-07-13
UAL129 United Airlines 12 2026-07-26
UAL947 - 11 2026-07-15
UAL52 United Airlines 11 2026-07-17
UAL53 United Airlines 10 2026-07-19
UAL21 United Airlines 10 2026-07-25
UAL126 United Airlines 9 2026-06-19
UAL243 United Airlines 7 2026-07-24
UAL242 United Airlines 7 2026-07-23
UAL127 United Airlines 7 2026-06-19
UAL946 United Airlines 5 2026-07-24
UAL330 United Airlines 4 2026-04-17
UAL331 United Airlines 3 2026-04-17
UAL322 - 3 2026-07-16
UAL749 United Airlines 2 2026-07-23
UAL748 United Airlines 2 2026-07-22
UAL3940 United Airlines 2 2026-05-21

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL129 IAH → GIG Jul 26, 01:30 UTCJul 26, 11:15 UTC9h 46m
2026-07-25 UAL21 AMS → IAH Jul 25, 09:50 UTCJul 25, 19:45 UTC9h 55m
2026-07-24 UAL946 IAD → AMS Jul 24, 23:25 UTCJul 25, 06:10 UTC6h 45m
2026-07-24 UAL243 SFO → BOI Jul 24, 08:35 UTCJul 24, 17:05 UTC8h 30m
2026-07-23 UAL242 PDX → SFO Jul 23, 22:05 UTCJul 24, 05:50 UTC7h 45m
2026-07-23 UAL749 CVG → DEN Jul 23, 09:15 UTCJul 23, 17:35 UTC8h 20m
2026-07-22 UAL748 PHL → ORD Jul 22, 21:45 UTCJul 23, 05:25 UTC7h 40m
2026-07-22 UAL243 - Jul 22, 10:20 UTCJul 22, 17:50 UTC7h 30m
2026-07-21 UAL243 - Jul 21, 22:50 UTCJul 22, 17:50 UTC19h 0m
2026-07-21 UAL242 PDX → SFO Jul 21, 21:48 UTCJul 22, 06:34 UTC8h 46m
2026-07-21 UAL749 GVA → IAD Jul 21, 09:20 UTCJul 21, 17:40 UTC8h 20m
2026-07-20 UAL748 PHL → ORD Jul 20, 21:40 UTCJul 21, 05:15 UTC7h 34m
2026-07-20 UAL243 NCE → IAD Jul 20, 09:55 UTCJul 20, 18:30 UTC8h 35m
2026-07-20 UAL243 NCE → IAD Jul 20, 09:59 UTCJul 20, 18:25 UTC8h 26m
2026-07-19 UAL242 PDX → SFO Jul 19, 22:43 UTCJul 20, 06:50 UTC8h 7m
2026-07-19 UAL242 PDX → SFO Jul 19, 22:55 UTCJul 20, 06:55 UTC8h 0m
2026-07-19 UAL53 ZRH → IAD Jul 19, 09:00 UTCJul 19, 09:40 UTC40m
2026-07-18 UAL53 ZRH → IAD Jul 18, 10:40 UTCJul 18, 20:20 UTC9h 40m
2026-07-17 UAL52 IAD → ZRH Jul 17, 22:00 UTCJul 18, 04:45 UTC6h 46m
2026-07-17 UAL52 IAD → ZRH Jul 17, 22:03 UTCJul 18, 05:41 UTC7h 38m
2026-07-17 UAL52 IAD → ZRH Jul 17, 21:39 UTCJul 17, 21:44 UTC5m
2026-07-17 UAL53 - Jul 17, 10:20 UTCJul 17, 10:44 UTC25m
2026-07-17 UAL53 ZRH → IAD Jul 17, 10:14 UTCJul 17, 19:03 UTC8h 49m
2026-07-16 UAL52 IAD → ZRH Jul 16, 22:35 UTCJul 17, 06:10 UTC7h 35m
2026-07-16 UAL52 IAD → ZRH Jul 16, 22:03 UTCJul 17, 06:04 UTC8h 1m
2026-07-16 UAL322 - Jul 16, 18:55 UTCJul 16, 19:40 UTC45m
2026-07-16 UAL322 - Jul 16, 10:45 UTCJul 16, 18:50 UTC8h 5m
2026-07-15 UAL321 - Jul 15, 23:50 UTCJul 16, 08:35 UTC8h 45m
2026-07-15 UAL947 - Jul 15, 09:35 UTCJul 15, 17:30 UTC7h 55m
2026-07-15 UAL947 AMS → IAD Jul 15, 09:35 UTCJul 15, 17:28 UTC7h 53m
2026-07-14 UAL20 - Jul 14, 21:50 UTCJul 15, 07:15 UTC9h 24m
2026-07-14 UAL855 - Jul 14, 06:35 UTCJul 14, 12:35 UTC6h 0m
2026-07-13 UAL854 - Jul 13, 21:50 UTCJul 14, 03:50 UTC6h 0m
2026-07-13 UAL128 - Jul 13, 01:35 UTCJul 13, 10:45 UTC9h 10m
2026-07-13 UAL128 - Jul 13, 00:30 UTCJul 13, 00:40 UTC10m
2026-07-13 UAL128 GIG → IAH Jul 13, 00:26 UTCJul 13, 10:42 UTC10h 16m
2026-07-12 UAL129 - Jul 12, 01:45 UTCJul 12, 02:15 UTC30m
2026-07-12 UAL129 IAH → GIG Jul 12, 01:41 UTCJul 12, 11:28 UTC9h 47m
2026-07-11 UAL855 - Jul 11, 06:45 UTCJul 11, 12:40 UTC5h 55m
2026-07-10 UAL854 - Jul 10, 21:50 UTCJul 11, 00:25 UTC2h 35m
2026-07-10 UAL854 IAH → LIM Jul 10, 21:57 UTCJul 11, 03:58 UTC6h 1m
2026-07-09 UAL855 - Jul 9, 07:20 UTCJul 9, 07:55 UTC35m
2026-07-09 UAL855 LIM → IAH Jul 9, 07:03 UTCJul 9, 13:06 UTC6h 3m
2026-07-08 UAL854 - Jul 8, 22:45 UTCJul 9, 04:50 UTC6h 5m
2026-07-08 UAL855 - Jul 8, 07:30 UTCJul 8, 13:10 UTC5h 40m
2026-07-07 UAL854 - Jul 7, 23:45 UTCJul 8, 05:15 UTC5h 30m
2026-07-07 UAL854 IAH → LIM Jul 7, 23:47 UTCJul 8, 05:33 UTC5h 46m
2026-07-07 UAL855 - Jul 7, 11:55 UTCJul 7, 12:20 UTC25m
2026-07-07 UAL855 - Jul 7, 06:25 UTCJul 7, 11:05 UTC4h 40m
2026-07-06 UAL854 - Jul 6, 21:35 UTCJul 6, 23:40 UTC2h 5m

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 N643UA page for operator, model, and routing details .

Mode-S A87223 frequently asked

What is Mode-S code A87223?
A87223 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N643UA.
Where is Mode-S A87223 registered?
Mode-S code A87223 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 A87223 broadcasting right now?
Yes. Mode-S A87223 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A87223, octal 52071043, decimal 11,039,267.
What flights does A87223 operate?
Mode-S A87223 has broadcast 20 distinct callsigns, including UAL855, UAL854, UAL20, UAL128, UAL129.