Apparatus

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sensors Mode-S transponder

AA75EF

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N773UA · BOEING 777-200 · operated by UNITED AIRLINES INC

Hex
AA75EF
Octal
52472757
Decimal
11,171,311
Country
US
Tail
N773UA
Type
B772
No current signal · last broadcast 2d ago
Flights observed
189
Distinct callsigns
20
Country
US
Last broadcast
2d ago

Last known position

Most recent position reported by Mode-S AA75EF.

Country allocation

The ICAO 24-bit address AA75EF 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
UAL1158 - 14 2026-07-09
UAL300 - 10 2026-07-07
UAL384 United Airlines 9 2026-07-02
UAL1170 - 9 2026-07-11
UAL1157 - 9 2026-07-09
UAL1818 - 8 2026-07-11
UAL1169 - 8 2026-07-09
UAL383 - 7 2026-06-29
UAL1806 United Airlines 7 2026-06-08
UAL1805 United Airlines 7 2026-06-08
UAL253 - 6 2026-07-08
UAL604 United Airlines 5 2026-07-06
UAL373 United Airlines 5 2026-04-16
UAL2358 United Airlines 5 2026-07-06
UAL1736 - 5 2026-06-29
UAL1731 United Airlines 5 2026-04-29
UAL252 - 4 2026-07-08
UAL2280 United Airlines 4 2026-06-12
UAL1777 United Airlines 4 2026-06-16
UAL1758 United Airlines 4 2026-04-28

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-11 UAL1818 - Jul 11, 23:50 UTCJul 12, 04:20 UTC4h 30m
2026-07-11 UAL1170 - Jul 11, 00:15 UTCJul 11, 05:20 UTC5h 5m
2026-07-09 UAL1157 - Jul 9, 23:50 UTCJul 10, 04:40 UTC4h 50m
2026-07-09 UAL1158 - Jul 9, 16:25 UTCJul 9, 21:40 UTC5h 15m
2026-07-09 UAL1158 LAX → HNL Jul 9, 16:21 UTCJul 9, 21:35 UTC5h 14m
2026-07-09 UAL1169 - Jul 9, 08:15 UTCJul 9, 12:55 UTC4h 40m
2026-07-08 UAL253 - Jul 8, 15:35 UTCJul 8, 23:20 UTC7h 45m
2026-07-08 UAL252 - Jul 8, 06:20 UTCJul 8, 13:20 UTC7h 0m
2026-07-07 UAL253 - Jul 7, 15:45 UTCJul 7, 23:25 UTC7h 40m
2026-07-07 UAL252 - Jul 7, 06:15 UTCJul 7, 13:10 UTC6h 55m
2026-07-07 UAL300 - Jul 7, 01:50 UTCJul 7, 02:15 UTC25m
2026-07-06 UAL300 - Jul 6, 21:35 UTCJul 6, 22:00 UTC25m
2026-07-06 UAL300 SFO → HNL Jul 6, 21:31 UTCJul 7, 02:14 UTC4h 43m
2026-07-06 UAL2358 SAN → EWR Jul 6, 15:15 UTCJul 6, 18:40 UTC3h 25m
2026-07-06 UAL604 DEN → SYR Jul 6, 08:20 UTCJul 6, 11:25 UTC3h 5m
2026-07-06 UAL1818 - Jul 6, 03:25 UTCJul 6, 04:00 UTC35m
2026-07-05 UAL1818 - Jul 5, 23:35 UTCJul 5, 23:45 UTC10m
2026-07-05 UAL1818 HNL → SFO Jul 5, 23:45 UTCJul 6, 03:55 UTC4h 10m
2026-07-05 UAL1158 - Jul 5, 21:05 UTCJul 5, 21:20 UTC15m
2026-07-05 UAL1158 - Jul 5, 16:15 UTCJul 5, 16:40 UTC25m
2026-07-05 UAL1158 LAX → HNL Jul 5, 16:21 UTCJul 5, 21:19 UTC4h 58m
2026-07-05 UAL1169 - Jul 5, 07:55 UTCJul 5, 12:35 UTC4h 40m
2026-07-05 UAL1170 - Jul 5, 00:20 UTCJul 5, 05:45 UTC5h 25m
2026-07-03 UAL1157 BOS → IAD Jul 3, 23:20 UTCJul 4, 03:50 UTC4h 30m
2026-07-02 UAL253 - Jul 2, 23:20 UTCJul 2, 23:35 UTC15m
2026-07-02 UAL253 - Jul 2, 15:50 UTCJul 2, 19:15 UTC3h 25m
2026-07-02 UAL252 - Jul 2, 06:15 UTCJul 2, 13:10 UTC6h 55m
2026-07-02 UAL384 DEN → HNL Jul 2, 01:05 UTCJul 2, 01:15 UTC10m
2026-07-01 UAL384 DEN → HNL Jul 1, 18:40 UTCJul 1, 21:00 UTC2h 20m
2026-06-29 UAL1736 DEN → DEN Jun 29, 18:34 UTCJun 30, 11:55 UTC17h 21m
2026-06-29 UAL383 - Jun 29, 07:05 UTCJun 29, 12:49 UTC5h 45m
2026-06-29 UAL384 DEN → HNL Jun 29, 00:54 UTCJun 29, 01:14 UTC20m
2026-06-28 UAL384 DEN → HNL Jun 28, 18:34 UTCJun 28, 21:04 UTC2h 30m
2026-06-25 UAL383 - Jun 25, 06:09 UTCJun 25, 12:04 UTC5h 55m
2026-06-24 UAL384 DEN → HNL Jun 24, 18:25 UTCJun 25, 01:09 UTC6h 45m
2026-06-19 UAL3933 - Jun 19, 23:09 UTCJun 20, 02:54 UTC3h 45m
2026-06-19 UAL435 SFO → EWR Jun 19, 15:39 UTCJun 19, 20:03 UTC4h 24m
2026-06-19 UAL435 SFO → EWR Jun 19, 15:39 UTCJun 19, 20:09 UTC4h 30m
2026-06-17 UAL1902 - Jun 17, 19:30 UTCJun 17, 23:55 UTC4h 25m
2026-06-16 UAL1777 EWR → IAH Jun 16, 22:35 UTCJun 17, 02:05 UTC3h 30m
2026-06-15 UAL8133 SFO → DEN Jun 15, 18:45 UTCJun 15, 22:15 UTC3h 30m
2026-06-15 UAL604 DEN → SYR Jun 15, 08:40 UTCJun 15, 12:00 UTC3h 20m
2026-06-14 UAL1902 IAH → GUA Jun 14, 19:05 UTCJun 14, 23:29 UTC4h 25m
2026-06-13 UAL1777 EWR → IAH Jun 13, 22:35 UTCJun 14, 02:00 UTC3h 25m
2026-06-13 UAL543 - Jun 13, 16:15 UTCJun 13, 20:30 UTC4h 15m
2026-06-12 UAL2475 ORD → CLE Jun 12, 17:10 UTCJun 12, 19:30 UTC2h 20m
2026-06-12 UAL2280 LAX → BOS Jun 12, 13:20 UTCJun 12, 15:25 UTC2h 5m
2026-06-12 UAL368T EWR → SYR Jun 12, 07:01 UTCJun 12, 10:02 UTC3h 1m
2026-06-12 UAL368T EWR → SYR Jun 12, 06:55 UTCJun 12, 10:10 UTC3h 15m
2026-06-11 UAL1818 FLL → EWR Jun 11, 23:55 UTCJun 12, 04:20 UTC4h 26m

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 N773UA page for operator, model, and routing details .

Mode-S AA75EF frequently asked

What is Mode-S code AA75EF?
AA75EF is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N773UA.
Where is Mode-S AA75EF registered?
Mode-S code AA75EF 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 AA75EF broadcasting right now?
No active broadcast right now. Last signal was 2d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AA75EF, octal 52472757, decimal 11,171,311.
What flights does AA75EF operate?
Mode-S AA75EF has broadcast 20 distinct callsigns, including UAL1158, UAL300, UAL384, UAL1170, UAL1157.