Apparatus

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sensors Mode-S transponder

AA7E99

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N77542 · BOEING 737-800 · operated by UNITED AIRLINES INC

Hex
AA7E99
Octal
52477231
Decimal
11,173,529
Country
US
Tail
N77542
Type
B738
Broadcasting now · callsign UAL525 · 8,600 ft
Flights observed
415
Distinct callsigns
20
Country
US
Last broadcast
11h ago

Current position

AA7E99 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address AA7E99 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
UAL2285 United Airlines 4 2026-05-12
UAL1609 United Airlines 4 2026-04-17
UAL1360 - 4 2026-07-03
UAL645 United Airlines 3 2026-06-11
UAL640 - 3 2026-07-10
UAL586 United Airlines 3 2026-06-09
UAL453 United Airlines 3 2026-06-08
UAL2786 - 3 2026-07-11
UAL2484 - 3 2026-04-16
UAL2457 United Airlines 3 2026-06-10
UAL2430 - 3 2026-06-29
UAL2270 - 3 2026-06-25
UAL2234 United Airlines 3 2026-05-16
UAL2167 - 3 2026-04-13
UAL216 United Airlines 3 2026-04-26
UAL2043 United Airlines 3 2026-06-10
UAL1931 - 3 2026-07-11
UAL1919 United Airlines 3 2026-04-19
UAL1915 - 3 2026-07-08
UAL1910 - 3 2026-07-10

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-13 UAL2337 IAD → AUS Jul 13, 22:20 UTCJul 14, 01:20 UTC3h 0m
2026-07-13 UAL1140 LAS → IAD Jul 13, 16:10 UTCJul 13, 20:20 UTC4h 10m
2026-07-13 UAL582 SFO → LAS Jul 13, 13:05 UTCJul 13, 14:15 UTC1h 10m
2026-07-13 UAL2056 - Jul 13, 05:01 UTCJul 13, 05:55 UTC55m
2026-07-13 UAL1427 - Jul 13, 02:01 UTCJul 13, 02:55 UTC55m
2026-07-11 UAL1931 - Jul 11, 21:45 UTCJul 11, 23:05 UTC1h 20m
2026-07-11 UAL1189 - Jul 11, 16:20 UTCJul 11, 17:45 UTC1h 25m
2026-07-11 UAL1189 SFO → SJD Jul 11, 16:08 UTCJul 11, 19:13 UTC3h 5m
2026-07-11 UAL1954 SMF → SFO Jul 11, 13:10 UTCJul 11, 13:35 UTC25m
2026-07-11 UAL8168 DEN → SMF Jul 11, 03:08 UTCJul 11, 05:15 UTC2h 7m
2026-07-11 UAL8168 DEN → SMF Jul 11, 03:10 UTCJul 11, 05:10 UTC2h 0m
2026-07-11 UAL2786 - Jul 11, 01:35 UTCJul 11, 01:40 UTC5m
2026-07-10 UAL2786 GEG → DEN Jul 10, 23:32 UTCJul 11, 01:20 UTC1h 48m
2026-07-10 UAL2786 GEG → DEN Jul 10, 23:20 UTCJul 11, 01:40 UTC2h 20m
2026-07-10 UAL324 DEN → GEG Jul 10, 20:05 UTCJul 10, 21:55 UTC1h 50m
2026-07-10 UAL640 - Jul 10, 15:55 UTCJul 10, 18:20 UTC2h 25m
2026-07-10 UAL1910 DEN → YVR Jul 10, 04:40 UTCJul 10, 07:10 UTC2h 30m
2026-07-09 UAL1001 - Jul 9, 23:25 UTCJul 10, 03:05 UTC3h 40m
2026-07-09 UAL2185 DEN → PNS Jul 9, 18:40 UTCJul 9, 21:05 UTC2h 25m
2026-07-09 UAL2750 - Jul 9, 12:10 UTCJul 9, 14:15 UTC2h 5m
2026-07-09 UAL2750 ALB → DEN Jul 9, 12:13 UTCJul 9, 15:49 UTC3h 36m
2026-07-09 UAL1662 DEN → ALB Jul 9, 01:00 UTCJul 9, 04:20 UTC3h 20m
2026-07-08 UAL302 - Jul 8, 19:55 UTCJul 8, 23:20 UTC3h 25m
2026-07-08 UAL1915 DEN → DTW Jul 8, 15:50 UTCJul 8, 18:15 UTC2h 25m
2026-07-08 UAL1774 - Jul 8, 12:15 UTCJul 8, 13:55 UTC1h 40m
2026-07-08 UAL1172 DEN → FAT Jul 8, 03:40 UTCJul 8, 05:44 UTC2h 4m
2026-07-08 UAL1172 - Jul 8, 03:55 UTCJul 8, 05:45 UTC1h 50m
2026-07-07 UAL1781 - Jul 7, 23:20 UTCJul 8, 01:20 UTC2h 0m
2026-07-07 UAL1311 - Jul 7, 19:45 UTCJul 7, 21:05 UTC1h 20m
2026-07-07 UAL1311 FLL → DEN Jul 7, 19:49 UTCJul 7, 21:07 UTC1h 18m
2026-07-07 UAL1191 BUR → DEN Jul 7, 16:25 UTCJul 7, 18:15 UTC1h 50m
2026-07-07 UAL2411 DEN → BUR Jul 7, 02:05 UTCJul 7, 04:00 UTC1h 55m
2026-07-06 UAL2644 PHL → DEN Jul 6, 20:30 UTCJul 7, 00:20 UTC3h 50m
2026-07-06 UAL1575 DEN → PHL Jul 6, 15:50 UTCJul 6, 18:55 UTC3h 5m
2026-07-06 UAL1291 LAS → DEN Jul 6, 01:40 UTCJul 6, 03:05 UTC1h 25m
2026-07-05 UAL716 DEN → LAS Jul 5, 22:25 UTCJul 5, 23:50 UTC1h 25m
2026-07-05 UAL2470 - Jul 5, 18:15 UTCJul 5, 20:30 UTC2h 15m
2026-07-05 UAL362 DEN → YVR Jul 5, 14:10 UTCJul 5, 16:40 UTC2h 30m
2026-07-04 UAL264 BGR → DEN Jul 4, 19:35 UTCJul 5, 00:10 UTC4h 35m
2026-07-04 UAL264 BGR → DEN Jul 4, 19:23 UTCJul 5, 00:05 UTC4h 42m
2026-07-04 UAL598 - Jul 4, 15:45 UTCJul 4, 17:45 UTC2h 0m
2026-07-04 UAL1316 ORD → ORD Jul 4, 07:20 UTCJul 4, 07:25 UTC5m
2026-07-04 UAL1316 - Jul 4, 05:10 UTCJul 4, 07:25 UTC2h 15m
2026-07-04 UAL1316 SAT → ORD Jul 4, 04:10 UTCJul 4, 07:03 UTC2h 53m
2026-07-03 UAL2844 - Jul 3, 20:55 UTCJul 3, 23:10 UTC2h 15m
2026-07-03 UAL2844 ORD → SAT Jul 3, 19:59 UTCJul 3, 23:13 UTC3h 14m
2026-07-03 UAL2635 LGA → ORD Jul 3, 15:40 UTCJul 3, 17:30 UTC1h 50m
2026-07-03 UAL1657 ORD → LGA Jul 3, 12:33 UTCJul 3, 13:45 UTC1h 12m
2026-07-03 UAL1657 - Jul 3, 12:10 UTCJul 3, 12:15 UTC5m
2026-07-03 UAL726 LAS → ORD Jul 3, 07:10 UTCJul 3, 10:20 UTC3h 10m

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 N77542 page for operator, model, and routing details .

Mode-S AA7E99 frequently asked

What is Mode-S code AA7E99?
AA7E99 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N77542.
Where is Mode-S AA7E99 registered?
Mode-S code AA7E99 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 AA7E99 broadcasting right now?
Yes. Mode-S AA7E99 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AA7E99, octal 52477231, decimal 11,173,529.
What flights does AA7E99 operate?
Mode-S AA7E99 has broadcast 20 distinct callsigns, including UAL2285, UAL1609, UAL1360, UAL645, UAL640.