Apparatus

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sensors Mode-S transponder

A2CA64

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N27908 · BOEING 787-8 Dreamliner · operated by UNITED AIRLINES INC

Hex
A2CA64
Octal
50545144
Decimal
10,668,644
Country
US
Tail
N27908
Type
B788
No current signal · last broadcast 3h ago
Flights observed
228
Distinct callsigns
20
Country
US
Last broadcast
3h ago

Last known position

Most recent position reported by Mode-S A2CA64.

Country allocation

The ICAO 24-bit address A2CA64 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
UAL770 - 24 2026-07-08
UAL769 - 24 2026-07-08
UAL908 - 16 2026-07-07
UAL952 - 15 2026-06-23
UAL909 United Airlines 14 2026-07-07
UAL981 - 11 2026-07-06
UAL980 - 10 2026-07-06
UAL953 - 9 2026-06-20
UAL612 - 9 2026-07-10
UAL109 United Airlines 9 2026-06-20
UAL108 United Airlines 9 2026-06-23
UAL996 - 8 2026-07-13
UAL982 - 8 2026-07-12
UAL983 - 7 2026-07-13
UAL613 - 7 2026-07-11
UAL415 United Airlines 5 2026-04-30
UAL997 - 4 2026-06-22
UAL423 - 4 2026-04-14
UAL416 United Airlines 4 2026-04-30
UAL3906 United Airlines 3 2026-04-26

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-13 UAL996 - Jul 13, 23:10 UTCJul 14, 06:40 UTC7h 30m
2026-07-13 UAL983 ATH → IAD Jul 13, 10:45 UTCJul 13, 20:50 UTC10h 5m
2026-07-12 UAL982 IAD → ATH Jul 12, 22:50 UTCJul 13, 08:15 UTC9h 25m
2026-07-12 UAL983 ATH → IAD Jul 12, 09:05 UTCJul 12, 19:17 UTC10h 12m
2026-07-12 UAL983 ATH → IAD Jul 12, 09:25 UTCJul 12, 19:15 UTC9h 50m
2026-07-11 UAL982 IAD → ATH Jul 11, 21:40 UTCJul 12, 06:50 UTC9h 10m
2026-07-11 UAL613 - Jul 11, 01:30 UTCJul 11, 09:25 UTC7h 55m
2026-07-10 UAL613 - Jul 10, 11:05 UTCJul 11, 09:25 UTC22h 20m
2026-07-10 UAL613 - Jul 10, 10:35 UTCJul 11, 09:00 UTC22h 25m
2026-07-10 UAL612 - Jul 10, 03:30 UTCJul 10, 11:30 UTC8h 0m
2026-07-10 UAL612 IAD → LOS Jul 10, 03:23 UTCJul 10, 14:01 UTC10h 38m
2026-07-09 UAL3907 - Jul 9, 23:40 UTCJul 10, 01:00 UTC1h 20m
2026-07-08 UAL770 BCN → ORD Jul 8, 13:41 UTCJul 8, 21:59 UTC8h 18m
2026-07-08 UAL770 BCN → ORD Jul 8, 13:30 UTCJul 8, 22:15 UTC8h 45m
2026-07-08 UAL769 ORD → BCN Jul 8, 03:15 UTCJul 8, 11:10 UTC7h 55m
2026-07-07 UAL908 AMS → ORD Jul 7, 10:20 UTCJul 7, 18:13 UTC7h 53m
2026-07-07 UAL908 - Jul 7, 10:10 UTCJul 7, 11:00 UTC50m
2026-07-07 UAL909 ORD → AMS Jul 7, 00:20 UTCJul 7, 07:00 UTC6h 40m
2026-07-07 UAL909 ORD → AMS Jul 7, 00:32 UTCJul 7, 07:23 UTC6h 51m
2026-07-06 UAL981 - Jul 6, 11:10 UTCJul 6, 18:25 UTC7h 15m
2026-07-06 UAL980 - Jul 6, 02:35 UTCJul 6, 09:10 UTC6h 35m
2026-07-05 UAL844 GRU → ORD Jul 5, 01:42 UTCJul 5, 11:01 UTC9h 19m
2026-07-05 UAL844 - Jul 5, 01:25 UTCJul 5, 02:00 UTC35m
2026-07-04 UAL845 ORD → GRU Jul 4, 05:20 UTCJul 4, 14:55 UTC9h 35m
2026-07-03 UAL908 - Jul 3, 20:40 UTCJul 3, 21:05 UTC25m
2026-07-03 UAL908 RFD → ORD Jul 3, 20:09 UTCJul 3, 20:20 UTC11m
2026-07-03 UAL908 - Jul 3, 10:30 UTCJul 3, 19:05 UTC8h 35m
2026-07-03 UAL909 ORD → AMS Jul 3, 00:25 UTCJul 3, 01:30 UTC1h 5m
2026-07-03 UAL909 ORD → AMS Jul 3, 00:12 UTCJul 3, 07:16 UTC7h 4m
2026-07-02 UAL981 - Jul 2, 11:30 UTCJul 2, 19:00 UTC7h 30m
2026-07-02 UAL980 - Jul 2, 02:35 UTCJul 2, 09:30 UTC6h 55m
2026-07-01 UAL981 - Jul 1, 11:25 UTCJul 1, 19:00 UTC7h 35m
2026-07-01 UAL980 - Jul 1, 02:30 UTCJul 1, 09:05 UTC6h 35m
2026-06-30 UAL908 AMS → ORD Jun 30, 12:00 UTCJun 30, 19:50 UTC7h 50m
2026-06-30 UAL908 AMS → ORD Jun 30, 11:50 UTCJun 30, 19:33 UTC7h 43m
2026-06-30 UAL909 ORD → AMS Jun 30, 02:37 UTCJun 30, 09:22 UTC6h 45m
2026-06-30 UAL909 ORD → AMS Jun 30, 02:20 UTCJun 30, 09:35 UTC7h 15m
2026-06-29 UAL770 BCN → ORD Jun 29, 13:41 UTCJun 29, 22:06 UTC8h 25m
2026-06-29 UAL770 BCN → ORD Jun 29, 13:30 UTCJun 29, 22:24 UTC8h 55m
2026-06-29 UAL769 ORD → BCN Jun 29, 03:10 UTCJun 29, 10:50 UTC7h 40m
2026-06-28 UAL203 - Jun 28, 06:15 UTCJun 28, 09:50 UTC3h 35m
2026-06-28 UAL203 OGG → ORD Jun 28, 02:16 UTCJun 28, 09:36 UTC7h 20m
2026-06-27 UAL202 - Jun 27, 15:10 UTCJun 27, 19:09 UTC4h 0m
2026-06-26 UAL908 AMS → ORD Jun 26, 10:30 UTCJun 26, 18:02 UTC7h 32m
2026-06-26 UAL908 AMS → ORD Jun 26, 10:30 UTCJun 26, 18:20 UTC7h 50m
2026-06-26 UAL909 ORD → AMS Jun 26, 00:12 UTCJun 26, 06:58 UTC6h 46m
2026-06-25 UAL909 ORD → AMS Jun 25, 23:59 UTCJun 26, 07:05 UTC7h 5m
2026-06-25 UAL908 - Jun 25, 10:15 UTCJun 25, 18:19 UTC8h 5m
2026-06-25 UAL909 ORD → AMS Jun 25, 00:49 UTCJun 25, 01:59 UTC1h 10m
2026-06-25 UAL909 ORD → AMS Jun 25, 00:12 UTCJun 25, 07:32 UTC7h 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 N27908 page for operator, model, and routing details .

Mode-S A2CA64 frequently asked

What is Mode-S code A2CA64?
A2CA64 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N27908.
Where is Mode-S A2CA64 registered?
Mode-S code A2CA64 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 A2CA64 broadcasting right now?
No active broadcast right now. Last signal was 3h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A2CA64, octal 50545144, decimal 10,668,644.
What flights does A2CA64 operate?
Mode-S A2CA64 has broadcast 20 distinct callsigns, including UAL770, UAL769, UAL908, UAL952, UAL909.