Apparatus

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sensors Mode-S transponder

A8EC57

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N674UA · BOEING 767-300 · operated by UNITED AIRLINES INC

Hex
A8EC57
Octal
52166127
Decimal
11,070,551
Country
US
Tail
N674UA
Type
B763
No current signal · last broadcast 1h ago
Flights observed
251
Distinct callsigns
20
Country
US
Last broadcast
1h ago

Last known position

Most recent position reported by Mode-S A8EC57.

Country allocation

The ICAO 24-bit address A8EC57 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
UAL959 - 16 2026-07-13
UAL929 - 14 2026-07-14
UAL965 - 13 2026-06-29
UAL964 - 12 2026-06-29
UAL17 - 11 2026-07-06
UAL146 - 10 2026-07-12
UAL135 - 10 2026-07-07
UAL928 United Airlines 9 2026-07-02
UAL16 - 9 2026-07-04
UAL908 United Airlines 8 2026-05-19
UAL958 - 7 2026-06-24
UAL921 - 7 2026-07-09
UAL904 - 7 2026-07-08
UAL381 United Airlines 7 2026-06-14
UAL273 - 7 2026-06-28
UAL134 - 7 2026-07-07
UAL934 United Airlines 6 2026-06-23
UAL31 - 6 2026-06-27
UAL30 - 6 2026-06-26
UAL3 United Airlines 6 2026-06-24

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-14 UAL929 - Jul 14, 00:40 UTCJul 14, 07:45 UTC7h 5m
2026-07-13 UAL959 - Jul 13, 10:40 UTCJul 13, 18:30 UTC7h 50m
2026-07-13 UAL940 EWR → LHR Jul 13, 01:21 UTCJul 13, 08:04 UTC6h 43m
2026-07-13 UAL940 EWR → LHR Jul 13, 01:15 UTCJul 13, 08:05 UTC6h 50m
2026-07-12 UAL15 LHR → EWR Jul 12, 14:55 UTCJul 12, 22:05 UTC7h 10m
2026-07-12 UAL146 EWR → LHR Jul 12, 02:29 UTCJul 12, 09:03 UTC6h 34m
2026-07-12 UAL146 - Jul 12, 02:30 UTCJul 12, 03:45 UTC1h 15m
2026-07-09 UAL921 - Jul 9, 20:00 UTCJul 9, 21:15 UTC1h 15m
2026-07-09 UAL921 LHR → EWR Jul 9, 19:53 UTCJul 10, 03:28 UTC7h 35m
2026-07-09 UAL921 LHR → EWR Jul 9, 19:53 UTCJul 10, 03:04 UTC7h 11m
2026-07-09 UAL920 ORD → LHR Jul 9, 00:20 UTCJul 9, 07:45 UTC7h 25m
2026-07-08 UAL959 - Jul 8, 10:40 UTCJul 8, 18:50 UTC8h 10m
2026-07-08 UAL904 EWR → LHR Jul 8, 00:20 UTCJul 8, 06:58 UTC6h 38m
2026-07-08 UAL904 EWR → LHR Jul 8, 00:15 UTCJul 8, 07:05 UTC6h 50m
2026-07-07 UAL135 ZRH → EWR Jul 7, 13:20 UTCJul 7, 21:34 UTC8h 14m
2026-07-07 UAL135 ZRH → EWR Jul 7, 13:10 UTCJul 7, 21:35 UTC8h 25m
2026-07-07 UAL134 - Jul 7, 03:15 UTCJul 7, 04:50 UTC1h 35m
2026-07-07 UAL134 EWR → ZRH Jul 7, 03:04 UTCJul 7, 10:25 UTC7h 21m
2026-07-06 UAL17 - Jul 6, 10:00 UTCJul 6, 17:25 UTC7h 25m
2026-07-06 UAL920 ORD → LHR Jul 6, 00:25 UTCJul 6, 07:55 UTC7h 30m
2026-07-05 UAL959 LHR → ORD Jul 5, 10:20 UTCJul 5, 18:25 UTC8h 5m
2026-07-05 UAL904 EWR → LHR Jul 5, 02:20 UTCJul 5, 08:40 UTC6h 20m
2026-07-04 UAL15 - Jul 4, 14:45 UTCJul 4, 22:25 UTC7h 40m
2026-07-04 UAL15 LHR → EWR Jul 4, 14:44 UTCJul 4, 22:20 UTC7h 36m
2026-07-04 UAL16 - Jul 4, 03:15 UTCJul 4, 09:50 UTC6h 35m
2026-07-03 UAL941 - Jul 3, 15:30 UTCJul 3, 23:05 UTC7h 35m
2026-07-03 UAL941 LHR → EWR Jul 3, 15:24 UTCJul 3, 23:01 UTC7h 37m
2026-07-03 UAL938 ORD → LHR Jul 3, 05:45 UTCJul 3, 13:00 UTC7h 15m
2026-07-02 UAL928 LHR → ORD Jul 2, 13:35 UTCJul 2, 22:05 UTC8h 30m
2026-07-02 UAL938 ORD → LHR Jul 2, 03:00 UTCJul 2, 10:20 UTC7h 20m
2026-07-01 UAL928 LHR → ORD Jul 1, 13:35 UTCJul 1, 22:05 UTC8h 30m
2026-07-01 UAL146 EWR → LHR Jul 1, 02:55 UTCJul 1, 09:25 UTC6h 30m
2026-06-29 UAL965 - Jun 29, 16:44 UTCJun 30, 01:55 UTC9h 11m
2026-06-29 UAL964 - Jun 29, 06:09 UTCJun 29, 13:59 UTC7h 50m
2026-06-28 UAL273 - Jun 28, 11:04 UTCJun 28, 11:45 UTC40m
2026-06-28 UAL273 NCE → EWR Jun 28, 10:50 UTCJun 28, 19:39 UTC8h 49m
2026-06-28 UAL273 NCE → EWR Jun 28, 10:50 UTCJun 28, 19:34 UTC8h 44m
2026-06-28 UAL272 EWR → NCE Jun 28, 00:00 UTCJun 28, 07:14 UTC7h 15m
2026-06-27 UAL31 MUC → EWR Jun 27, 08:10 UTCJun 27, 16:30 UTC8h 20m
2026-06-26 UAL30 - Jun 26, 21:39 UTCJun 27, 04:54 UTC7h 15m
2026-06-26 UAL31 MUC → EWR Jun 26, 08:05 UTCJun 26, 16:35 UTC8h 30m
2026-06-25 UAL30 - Jun 25, 21:20 UTCJun 26, 04:30 UTC7h 10m
2026-06-25 UAL135 ZRH → EWR Jun 25, 08:34 UTCJun 25, 17:09 UTC8h 35m
2026-06-24 UAL3 LAX → HNL Jun 24, 21:44 UTCJun 25, 05:44 UTC8h 0m
2026-06-24 UAL958 - Jun 24, 07:20 UTCJun 24, 15:29 UTC8h 10m
2026-06-23 UAL934 EWR → LHR Jun 23, 12:45 UTCJun 23, 19:04 UTC6h 20m
2026-06-22 UAL921 - Jun 22, 17:34 UTCJun 23, 01:04 UTC7h 30m
2026-06-21 UAL16 - Jun 21, 21:39 UTCJun 22, 04:09 UTC6h 30m
2026-06-21 UAL31 - Jun 21, 08:10 UTCJun 21, 15:44 UTC7h 35m
2026-06-21 UAL31 MUC → EWR Jun 21, 08:07 UTCJun 21, 16:34 UTC8h 27m

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 N674UA page for operator, model, and routing details .

Mode-S A8EC57 frequently asked

What is Mode-S code A8EC57?
A8EC57 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N674UA.
Where is Mode-S A8EC57 registered?
Mode-S code A8EC57 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 A8EC57 broadcasting right now?
No active broadcast right now. Last signal was 1h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A8EC57, octal 52166127, decimal 11,070,551.
What flights does A8EC57 operate?
Mode-S A8EC57 has broadcast 20 distinct callsigns, including UAL959, UAL929, UAL965, UAL964, UAL17.