Apparatus

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sensors Mode-S transponder

AAA590

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N78506 · BOEING 737-800 · operated by UNITED AIRLINES INC

Hex
AAA590
Octal
52522620
Decimal
11,183,504
Country
US
Tail
N78506
Type
B738
No current signal · last broadcast Jul 26, 21:30 UTC
Flights observed
447
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 21:30 UTC

Last known position

Most recent position reported by Mode-S AAA590.

Country allocation

The ICAO 24-bit address AAA590 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
UAL1881 - 7 2026-07-12
UAL586 - 5 2026-06-26
UAL476 - 5 2026-06-23
UAL1006 United Airlines 5 2026-07-22
UAL751 United Airlines 4 2026-07-22
UAL678 - 4 2026-06-16
UAL565 - 4 2026-07-12
UAL378 United Airlines 4 2026-07-26
UAL372 United Airlines 4 2026-07-22
UAL294 - 4 2026-07-02
UAL2643 United Airlines 4 2026-05-10
UAL2267 - 4 2026-07-10
UAL1737 - 4 2026-06-29
UAL1657 - 4 2026-07-23
UAL705 United Airlines 3 2026-06-17
UAL669 United Airlines 3 2026-07-20
UAL488 - 3 2026-07-14
UAL470 United Airlines 3 2026-04-24
UAL396 United Airlines 3 2026-05-11
UAL341 United Airlines 3 2026-04-25

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL2124 PDX → SFO Jul 26, 20:10 UTCJul 26, 21:30 UTC1h 20m
2026-07-26 UAL378 ORD → EWR Jul 26, 16:15 UTCJul 26, 18:15 UTC2h 0m
2026-07-26 UAL762 SFO → IAH Jul 26, 12:30 UTCJul 26, 14:10 UTC1h 40m
2026-07-26 UAL2094 IAH → LGA Jul 26, 05:55 UTCJul 26, 09:20 UTC3h 26m
2026-07-26 UAL2262 LAS → SFO Jul 26, 02:10 UTCJul 26, 03:20 UTC1h 10m
2026-07-25 UAL1212 SFO → PVR Jul 25, 15:55 UTCJul 25, 23:55 UTC8h 0m
2026-07-25 UAL1896 SEA → SFO Jul 25, 12:30 UTCJul 25, 14:05 UTC1h 35m
2026-07-24 UAL2817 EWR → LHR Jul 24, 21:10 UTCJul 25, 01:00 UTC3h 50m
2026-07-24 UAL378 ORD → EWR Jul 24, 16:30 UTCJul 24, 18:35 UTC2h 5m
2026-07-24 UAL762 ORD → BDL Jul 24, 13:45 UTCJul 24, 15:20 UTC1h 35m
2026-07-24 UAL1856 DEN → SFO Jul 24, 11:15 UTCJul 24, 12:30 UTC1h 15m
2026-07-24 UAL1839 SAN → DEN Jul 24, 03:20 UTCJul 24, 04:10 UTC50m
2026-07-23 UAL1098 EWR → DEN Jul 23, 22:50 UTCJul 24, 00:45 UTC1h 55m
2026-07-23 UAL1821 PHL → ORD Jul 23, 19:40 UTCJul 23, 21:25 UTC1h 45m
2026-07-23 UAL2635 IAH → LGA Jul 23, 16:15 UTCJul 23, 18:10 UTC1h 55m
2026-07-23 UAL1657 - Jul 23, 13:20 UTCJul 23, 14:55 UTC1h 35m
2026-07-23 UAL1657 ORD → LGA Jul 23, 13:34 UTCJul 23, 14:50 UTC1h 16m
2026-07-23 UAL2805 EWR → HNL Jul 23, 11:10 UTCJul 23, 11:55 UTC45m
2026-07-23 UAL214 HNL → SFO Jul 23, 04:45 UTCJul 23, 06:25 UTC1h 40m
2026-07-23 UAL1910 EWR → DEN Jul 23, 02:25 UTCJul 23, 03:25 UTC1h 0m
2026-07-22 UAL2017 IAH → BOS Jul 22, 22:45 UTCJul 23, 00:05 UTC1h 20m
2026-07-22 UAL372 HNL → SFO Jul 22, 20:35 UTCJul 22, 21:30 UTC55m
2026-07-22 UAL372 HNL → SFO Jul 22, 20:43 UTCJul 22, 21:25 UTC42m
2026-07-22 UAL203 SFO → ABQ Jul 22, 17:50 UTCJul 22, 18:35 UTC45m
2026-07-22 UAL1006 LAX → SFO Jul 22, 15:30 UTCJul 22, 16:15 UTC45m
2026-07-22 UAL2039 LAX → ORD Jul 22, 13:10 UTCJul 22, 13:50 UTC40m
2026-07-22 UAL2282 SAN → IAD Jul 22, 04:15 UTCJul 22, 05:00 UTC45m
2026-07-22 UAL751 EWR → SFO Jul 22, 01:03 UTCJul 22, 02:15 UTC1h 12m
2026-07-22 UAL751 EWR → SFO Jul 22, 01:05 UTCJul 22, 02:15 UTC1h 10m
2026-07-21 UAL2823 IAD → EWR Jul 21, 22:55 UTCJul 21, 23:55 UTC1h 0m
2026-07-21 UAL571 AUS → SFO Jul 21, 19:30 UTCJul 21, 20:40 UTC1h 10m
2026-07-21 UAL2153 - Jul 21, 11:15 UTCJul 21, 15:50 UTC4h 35m
2026-07-20 UAL2652 - Jul 20, 23:20 UTCJul 21, 00:10 UTC49m
2026-07-20 UAL2199 LGA → DEN Jul 20, 18:35 UTCJul 20, 20:45 UTC2h 10m
2026-07-20 UAL669 EWR → AUS Jul 20, 15:30 UTCJul 20, 17:05 UTC1h 35m
2026-07-20 UAL2822 LGA → ORD Jul 20, 11:55 UTCJul 20, 14:10 UTC2h 15m
2026-07-20 UAL1623 ORD → LGA Jul 20, 00:00 UTCJul 20, 01:40 UTC1h 40m
2026-07-19 UAL1180 ORD → ORD Jul 19, 14:55 UTCJul 19, 22:05 UTC7h 10m
2026-07-19 UAL2752 - Jul 19, 11:25 UTCJul 19, 12:30 UTC1h 5m
2026-07-19 UAL2148 ORD → CVG Jul 19, 03:05 UTCJul 19, 03:55 UTC50m
2026-07-18 UAL1968 YYC → ORD Jul 18, 14:50 UTCJul 18, 17:40 UTC2h 50m
2026-07-18 UAL1156 IAD → EWR Jul 18, 02:00 UTCJul 18, 05:00 UTC3h 1m
2026-07-17 UAL2422 - Jul 17, 21:00 UTCJul 18, 00:00 UTC3h 0m
2026-07-17 UAL2401 - Jul 17, 16:40 UTCJul 17, 19:09 UTC2h 30m
2026-07-17 UAL1297 - Jul 17, 12:19 UTCJul 17, 14:00 UTC1h 40m
2026-07-17 UAL1965 - Jul 17, 00:40 UTCJul 17, 05:25 UTC4h 45m
2026-07-16 UAL372 - Jul 16, 22:05 UTCJul 16, 22:59 UTC55m
2026-07-16 UAL203 - Jul 16, 17:54 UTCJul 16, 18:34 UTC40m
2026-07-16 UAL1006 - Jul 16, 15:35 UTCJul 16, 16:19 UTC45m
2026-07-16 UAL1006 SAN → LAX Jul 16, 13:42 UTCJul 16, 13:49 UTC7m

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 N78506 page for operator, model, and routing details .

Mode-S AAA590 frequently asked

What is Mode-S code AAA590?
AAA590 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N78506.
Where is Mode-S AAA590 registered?
Mode-S code AAA590 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 AAA590 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 21:30 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AAA590, octal 52522620, decimal 11,183,504.
What flights does AAA590 operate?
Mode-S AAA590 has broadcast 20 distinct callsigns, including UAL1881, UAL586, UAL476, UAL1006, UAL751.