Apparatus

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sensors Mode-S transponder

A899A2

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N653UA · BOEING 767-300 · operated by UNITED AIRLINES INC

Hex
A899A2
Octal
52114642
Decimal
11,049,378
Country
US
Tail
N653UA
Type
B763
No current signal · last broadcast 2h ago
Flights observed
228
Distinct callsigns
20
Country
US
Last broadcast
2h ago

Last known position

Most recent position reported by Mode-S A899A2.

Country allocation

The ICAO 24-bit address A899A2 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
UAL957 United Airlines 12 2026-06-21
UAL941 - 11 2026-06-24
UAL3 - 11 2026-07-09
UAL958 - 10 2026-07-04
UAL904 - 10 2026-07-07
UAL17 - 10 2026-06-17
UAL146 - 10 2026-06-25
UAL962 United Airlines 9 2026-07-05
UAL135 - 8 2026-07-05
UAL965 - 7 2026-06-19
UAL963 - 7 2026-07-06
UAL956 - 7 2026-06-20
UAL55 United Airlines 7 2026-05-07
UAL12 - 7 2026-07-10
UAL273 - 6 2026-06-29
UAL966 - 5 2026-06-23
UAL959 - 5 2026-07-11
UAL934 United Airlines 5 2026-06-30
UAL921 United Airlines 5 2026-06-01
UAL54 United Airlines 5 2026-05-07

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-14 UAL31 - Jul 14, 08:10 UTCJul 14, 10:30 UTC2h 20m
2026-07-13 UAL30 EWR → MUC Jul 13, 21:55 UTCJul 14, 05:24 UTC7h 29m
2026-07-13 UAL30 - Jul 13, 21:55 UTCJul 14, 05:25 UTC7h 30m
2026-07-13 UAL147 - Jul 13, 11:55 UTCJul 13, 19:00 UTC7h 5m
2026-07-13 UAL920 ORD → LHR Jul 13, 00:20 UTCJul 13, 08:05 UTC7h 45m
2026-07-12 UAL119 - Jul 12, 13:10 UTCJul 12, 13:40 UTC30m
2026-07-12 UAL119 EDI → ORD Jul 12, 13:13 UTCJul 12, 20:34 UTC7h 21m
2026-07-12 UAL118 ORD → EDI Jul 12, 03:40 UTCJul 12, 10:40 UTC7h 0m
2026-07-11 UAL959 LHR → ORD Jul 11, 10:30 UTCJul 11, 18:35 UTC8h 5m
2026-07-11 UAL920 - Jul 11, 06:25 UTCJul 11, 07:50 UTC1h 25m
2026-07-11 UAL920 - Jul 11, 00:25 UTCJul 11, 02:40 UTC2h 15m
2026-07-10 UAL12 ZRH → ORD Jul 10, 08:10 UTCJul 10, 17:15 UTC9h 5m
2026-07-09 UAL3 ORD → ZRH Jul 9, 21:42 UTCJul 10, 05:20 UTC7h 38m
2026-07-09 UAL3 - Jul 9, 21:25 UTCJul 10, 04:30 UTC7h 5m
2026-07-09 UAL12 ZRH → ORD Jul 9, 08:20 UTCJul 9, 17:25 UTC9h 5m
2026-07-08 UAL3 ORD → ZRH Jul 8, 21:32 UTCJul 9, 05:29 UTC7h 57m
2026-07-08 UAL3 ORD → ZRH Jul 8, 21:25 UTCJul 9, 05:20 UTC7h 55m
2026-07-07 UAL959 - Jul 7, 10:25 UTCJul 7, 18:45 UTC8h 20m
2026-07-07 UAL904 EWR → LHR Jul 7, 01:10 UTCJul 7, 07:45 UTC6h 35m
2026-07-06 UAL963 - Jul 6, 08:10 UTCJul 6, 16:45 UTC8h 35m
2026-07-05 UAL962 EWR → BER Jul 5, 21:25 UTCJul 6, 04:35 UTC7h 10m
2026-07-05 UAL135 ZRH → EWR Jul 5, 09:00 UTCJul 5, 17:46 UTC8h 46m
2026-07-05 UAL135 ZRH → EWR Jul 5, 09:05 UTCJul 5, 17:35 UTC8h 30m
2026-07-04 UAL3 LAX → HNL Jul 4, 21:52 UTCJul 5, 05:41 UTC7h 49m
2026-07-04 UAL3 LAX → HNL Jul 4, 21:40 UTCJul 5, 05:45 UTC8h 5m
2026-07-04 UAL958 - Jul 4, 07:20 UTCJul 4, 15:45 UTC8h 25m
2026-07-04 UAL958 LHR → ORD Jul 4, 07:19 UTCJul 4, 15:36 UTC8h 17m
2026-07-03 UAL929 ORD → LHR Jul 3, 22:15 UTCJul 4, 05:30 UTC7h 15m
2026-07-03 UAL12 ZRH → ORD Jul 3, 08:15 UTCJul 3, 18:05 UTC9h 50m
2026-07-02 UAL3 LAX → HNL Jul 2, 22:00 UTCJul 3, 05:55 UTC7h 55m
2026-07-02 UAL12 ZRH → ORD Jul 2, 08:23 UTCJul 2, 17:36 UTC9h 13m
2026-07-02 UAL12 ZRH → ORD Jul 2, 08:15 UTCJul 2, 17:40 UTC9h 25m
2026-07-01 UAL3 LAX → HNL Jul 1, 21:10 UTCJul 2, 05:15 UTC8h 5m
2026-07-01 UAL958 - Jul 1, 07:10 UTCJul 1, 15:35 UTC8h 25m
2026-06-30 UAL934 EWR → LHR Jun 30, 13:00 UTCJun 30, 19:15 UTC6h 15m
2026-06-29 UAL273 - Jun 29, 10:34 UTCJun 29, 12:39 UTC2h 5m
2026-06-29 UAL273 NCE → EWR Jun 29, 10:30 UTCJun 29, 19:30 UTC9h 0m
2026-06-29 UAL273 NCE → EWR Jun 29, 10:30 UTCJun 29, 19:30 UTC9h 0m
2026-06-29 UAL272 EWR → NCE Jun 29, 00:24 UTCJun 29, 07:30 UTC7h 5m
2026-06-26 UAL937 NCE → EWR Jun 26, 15:10 UTCJun 26, 23:30 UTC8h 20m
2026-06-26 UAL936 EWR → NCE Jun 26, 05:54 UTCJun 26, 12:51 UTC6h 57m
2026-06-26 UAL936 - Jun 26, 05:44 UTCJun 26, 12:29 UTC6h 45m
2026-06-25 UAL147 - Jun 25, 11:35 UTCJun 25, 12:50 UTC1h 15m
2026-06-25 UAL147 LHR → EWR Jun 25, 11:25 UTCJun 25, 19:05 UTC7h 40m
2026-06-25 UAL146 - Jun 25, 02:45 UTCJun 25, 09:14 UTC6h 30m
2026-06-25 UAL146 EWR → LHR Jun 25, 02:44 UTCJun 25, 09:12 UTC6h 28m
2026-06-25 UAL146 EWR → EWR Jun 25, 02:25 UTCJun 25, 02:35 UTC10m
2026-06-24 UAL941 - Jun 24, 15:29 UTCJun 24, 22:55 UTC7h 25m
2026-06-24 UAL940 EWR → LHR Jun 24, 05:16 UTCJun 24, 10:51 UTC5h 35m
2026-06-24 UAL940 - Jun 24, 04:55 UTCJun 24, 10:30 UTC5h 35m

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 N653UA page for operator, model, and routing details .

Mode-S A899A2 frequently asked

What is Mode-S code A899A2?
A899A2 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N653UA.
Where is Mode-S A899A2 registered?
Mode-S code A899A2 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 A899A2 broadcasting right now?
No active broadcast right now. Last signal was 2h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A899A2, octal 52114642, decimal 11,049,378.
What flights does A899A2 operate?
Mode-S A899A2 has broadcast 20 distinct callsigns, including UAL957, UAL941, UAL3, UAL958, UAL904.