Apparatus

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sensors Mode-S transponder

A8C4D8

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N664UA · BOEING 767-300 · operated by UNITED AIRLINES INC

Hex
A8C4D8
Octal
52142330
Decimal
11,060,440
Country
US
Tail
N664UA
Type
B763
Broadcasting now · callsign UAL381 · 32,000 ft
Flights observed
130
Distinct callsigns
20
Country
US
Last broadcast
4h ago

Current position

A8C4D8 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A8C4D8 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
UAL15 - 14 2026-07-11
UAL965 - 7 2026-06-22
UAL904 - 7 2026-07-11
UAL273 - 7 2026-07-05
UAL272 - 7 2026-07-05
UAL958 - 6 2026-06-29
UAL928 United Airlines 6 2026-06-10
UAL956 - 5 2026-07-05
UAL921 - 5 2026-06-30
UAL920 United Airlines 5 2026-06-27
UAL146 United Airlines 5 2026-04-21
UAL964 - 4 2026-06-21
UAL962 United Airlines 4 2026-07-01
UAL957 United Airlines 4 2026-07-06
UAL938 - 4 2026-06-30
UAL17 United Airlines 4 2026-04-27
UAL12 - 4 2026-06-15
UAL16 - 3 2026-07-06
UAL122 United Airlines 3 2026-04-16
UAL966 - 2 2026-07-08

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-13 UAL380 EWR → BRI Jul 13, 21:10 UTCJul 14, 05:25 UTC8h 15m
2026-07-11 UAL15 LHR → EWR Jul 11, 15:05 UTCJul 11, 22:30 UTC7h 25m
2026-07-11 UAL15 LHR → EWR Jul 11, 14:44 UTCJul 11, 22:23 UTC7h 39m
2026-07-11 UAL904 - Jul 11, 00:30 UTCJul 11, 07:05 UTC6h 35m
2026-07-11 UAL904 EWR → LHR Jul 11, 00:20 UTCJul 11, 06:56 UTC6h 36m
2026-07-08 UAL967 - Jul 8, 12:30 UTCJul 8, 21:55 UTC9h 25m
2026-07-08 UAL966 EWR → NAP Jul 8, 01:11 UTCJul 8, 09:17 UTC8h 6m
2026-07-08 UAL966 - Jul 8, 01:05 UTCJul 8, 08:00 UTC6h 55m
2026-07-07 UAL15 - Jul 7, 14:45 UTCJul 7, 21:55 UTC7h 10m
2026-07-07 UAL15 LHR → EWR Jul 7, 14:44 UTCJul 7, 21:54 UTC7h 10m
2026-07-06 UAL16 EWR → LHR Jul 6, 22:33 UTCJul 7, 05:31 UTC6h 58m
2026-07-06 UAL16 - Jul 6, 23:05 UTCJul 7, 00:40 UTC1h 35m
2026-07-06 UAL957 GVA → EWR Jul 6, 07:30 UTCJul 6, 15:45 UTC8h 15m
2026-07-05 UAL956 EWR → GVA Jul 5, 22:03 UTCJul 6, 05:20 UTC7h 17m
2026-07-05 UAL956 - Jul 5, 22:35 UTCJul 6, 04:00 UTC5h 25m
2026-07-05 UAL273 - Jul 5, 10:40 UTCJul 5, 12:50 UTC2h 10m
2026-07-05 UAL273 NCE → EWR Jul 5, 10:30 UTCJul 5, 19:25 UTC8h 55m
2026-07-05 UAL272 EWR → NCE Jul 5, 00:10 UTCJul 5, 07:35 UTC7h 25m
2026-07-04 UAL957 GVA → EWR Jul 4, 07:35 UTCJul 4, 15:55 UTC8h 20m
2026-07-03 UAL956 EWR → GVA Jul 3, 22:12 UTCJul 4, 05:39 UTC7h 27m
2026-07-03 UAL956 - Jul 3, 22:35 UTCJul 4, 00:00 UTC1h 25m
2026-07-03 UAL273 - Jul 3, 11:15 UTCJul 3, 19:50 UTC8h 35m
2026-07-03 UAL273 NCE → EWR Jul 3, 10:50 UTCJul 3, 19:50 UTC9h 0m
2026-07-03 UAL272 EWR → NCE Jul 3, 01:00 UTCJul 3, 08:31 UTC7h 31m
2026-07-03 UAL272 - Jul 3, 00:50 UTCJul 3, 01:40 UTC50m
2026-07-02 UAL273 NCE → EWR Jul 2, 11:15 UTCJul 2, 20:15 UTC9h 0m
2026-07-02 UAL272 EWR → NCE Jul 2, 00:20 UTCJul 2, 07:55 UTC7h 35m
2026-07-02 UAL272 EWR → NCE Jul 2, 00:35 UTCJul 2, 08:00 UTC7h 25m
2026-07-01 UAL963 - Jul 1, 12:55 UTCJul 1, 21:25 UTC8h 30m
2026-07-01 UAL962 EWR → BER Jul 1, 03:57 UTCJul 1, 10:52 UTC6h 55m
2026-07-01 UAL962 EWR → BER Jul 1, 03:55 UTCJul 1, 10:55 UTC7h 0m
2026-06-30 UAL921 - Jun 30, 17:45 UTCJul 1, 00:55 UTC7h 10m
2026-06-30 UAL938 ORD → LHR Jun 30, 04:13 UTCJun 30, 11:12 UTC6h 59m
2026-06-30 UAL938 ORD → LHR Jun 30, 04:05 UTCJun 30, 11:20 UTC7h 15m
2026-06-29 UAL958 - Jun 29, 13:09 UTCJun 29, 15:30 UTC2h 20m
2026-06-29 UAL958 - Jun 29, 07:05 UTCJun 29, 13:04 UTC6h 0m
2026-06-28 UAL934 EWR → LHR Jun 28, 12:57 UTCJun 28, 19:12 UTC6h 15m
2026-06-28 UAL934 EWR → LHR Jun 28, 12:50 UTCJun 28, 19:29 UTC6h 40m
2026-06-27 UAL921 - Jun 27, 17:14 UTCJun 28, 00:15 UTC7h 0m
2026-06-27 UAL920 ORD → LHR Jun 27, 09:34 UTCJun 27, 14:29 UTC4h 55m
2026-06-27 UAL920 ORD → LHR Jun 27, 07:42 UTCJun 27, 14:25 UTC6h 43m
2026-06-27 UAL920 ORD → LHR Jun 27, 07:19 UTCJun 27, 09:29 UTC2h 10m
2026-06-25 UAL959 - Jun 25, 10:39 UTCJun 25, 18:50 UTC8h 10m
2026-06-25 UAL904 EWR → LHR Jun 25, 00:14 UTCJun 25, 06:50 UTC6h 35m
2026-06-24 UAL957 GVA → EWR Jun 24, 07:34 UTCJun 24, 09:29 UTC1h 55m
2026-06-24 UAL957 GVA → EWR Jun 24, 07:37 UTCJun 24, 16:03 UTC8h 26m
2026-06-23 UAL956 EWR → GVA Jun 23, 22:29 UTCJun 24, 05:29 UTC7h 0m
2026-06-23 UAL963 BER → EWR Jun 23, 08:04 UTCJun 23, 16:44 UTC8h 40m
2026-06-22 UAL962 EWR → BER Jun 22, 21:43 UTCJun 23, 05:11 UTC7h 28m
2026-06-22 UAL962 EWR → BER Jun 22, 22:10 UTCJun 23, 04:00 UTC5h 50m

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 N664UA page for operator, model, and routing details .

Mode-S A8C4D8 frequently asked

What is Mode-S code A8C4D8?
A8C4D8 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N664UA.
Where is Mode-S A8C4D8 registered?
Mode-S code A8C4D8 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 A8C4D8 broadcasting right now?
Yes. Mode-S A8C4D8 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A8C4D8, octal 52142330, decimal 11,060,440.
What flights does A8C4D8 operate?
Mode-S A8C4D8 has broadcast 20 distinct callsigns, including UAL15, UAL965, UAL904, UAL273, UAL272.