Apparatus

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sensors Mode-S transponder

A4A533

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N399LA · PILATUS PC-12 · operated by TVPX AIRCRAFT SOLUTIONS INC TRUSTEE

Hex
A4A533
Octal
51122463
Decimal
10,790,195
Country
US
Tail
N399LA
Type
PC12
No current signal · last broadcast Jul 18, 02:50 UTC
Flights observed
393
Distinct callsigns
20
Country
US
Last broadcast
Jul 18, 02:50 UTC

Last known position

Most recent position reported by Mode-S A4A533.

Country allocation

The ICAO 24-bit address A4A533 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
STT228 - 36 2026-07-16
STT208 - 35 2026-07-12
STT204 - 33 2026-07-12
STT224 - 32 2026-07-13
STT329 - 31 2026-07-16
STT305 - 30 2026-07-12
STT218 - 29 2026-07-13
STT319 - 28 2026-07-15
STT309 - 28 2026-07-12
STT325 - 26 2026-07-16
STT694 - 6 2026-07-17
STT791 Air St. Thomas 4 2026-06-15
STT690 - 4 2026-07-10
STT222 - 4 2026-07-15
STT216 - 4 2026-07-14
STT995 Air St. Thomas 3 2026-05-15
STT933 - 3 2026-07-17
STT795 Air St. Thomas 3 2026-05-16
STT72 - 3 2026-07-06
STT692 Air St. Thomas 3 2026-06-08

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-18 STT945 MKK → HNL Jul 18, 02:19 UTCJul 18, 02:50 UTC31m
2026-07-18 STT944 HNL → JHM Jul 18, 01:39 UTCJul 18, 02:05 UTC25m
2026-07-18 STT939 - Jul 18, 00:39 UTCJul 18, 00:55 UTC15m
2026-07-17 STT5026 LNY → KOA Jul 17, 23:20 UTCJul 17, 23:45 UTC25m
2026-07-17 STT5026 LNY → KOA Jul 17, 21:55 UTCJul 17, 22:29 UTC35m
2026-07-17 STT694 - Jul 17, 21:00 UTCJul 17, 21:20 UTC20m
2026-07-17 STT933 - Jul 17, 19:40 UTCJul 17, 20:00 UTC20m
2026-07-17 STT942 LNY → OGG Jul 17, 18:29 UTCJul 17, 18:50 UTC20m
2026-07-16 STT329 - Jul 16, 05:05 UTCJul 16, 05:30 UTC25m
2026-07-16 STT228 - Jul 16, 04:05 UTCJul 16, 04:25 UTC20m
2026-07-16 STT325 - Jul 16, 02:05 UTCJul 16, 03:15 UTC1h 10m
2026-07-15 STT319 - Jul 15, 23:10 UTCJul 16, 00:15 UTC1h 5m
2026-07-15 STT937 - Jul 15, 19:15 UTCJul 15, 19:30 UTC15m
2026-07-15 STT936 - Jul 15, 17:50 UTCJul 15, 18:05 UTC15m
2026-07-15 STT935 - Jul 15, 02:50 UTCJul 15, 03:35 UTC45m
2026-07-15 STT222 - Jul 15, 00:50 UTCJul 15, 02:05 UTC1h 15m
2026-07-14 STT216 - Jul 14, 22:05 UTCJul 14, 23:10 UTC1h 4m
2026-07-14 STT934 - Jul 14, 03:15 UTCJul 14, 04:15 UTC1h 0m
2026-07-14 STT323 - Jul 14, 01:55 UTCJul 14, 02:15 UTC20m
2026-07-14 STT222 - Jul 14, 00:55 UTCJul 14, 01:15 UTC20m
2026-07-13 STT218 - Jul 13, 23:10 UTCJul 14, 00:15 UTC1h 5m
2026-07-13 STT696 - Jul 13, 21:35 UTCJul 13, 22:30 UTC55m
2026-07-13 STT329 - Jul 13, 04:55 UTCJul 13, 05:15 UTC20m
2026-07-13 STT228 - Jul 13, 04:00 UTCJul 13, 04:20 UTC20m
2026-07-13 STT325 - Jul 13, 03:01 UTCJul 13, 03:20 UTC20m
2026-07-13 STT224 - Jul 13, 02:10 UTCJul 13, 02:30 UTC20m
2026-07-13 STT321 - Jul 13, 00:15 UTCJul 13, 01:30 UTC1h 15m
2026-07-12 STT216 - Jul 12, 22:10 UTCJul 12, 23:20 UTC1h 10m
2026-07-12 STT212 - Jul 12, 20:05 UTCJul 12, 21:15 UTC1h 10m
2026-07-12 STT309 - Jul 12, 18:55 UTCJul 12, 19:15 UTC20m
2026-07-12 STT208 - Jul 12, 17:55 UTCJul 12, 18:15 UTC20m
2026-07-12 STT305 - Jul 12, 16:55 UTCJul 12, 17:15 UTC20m
2026-07-12 STT204 - Jul 12, 16:01 UTCJul 12, 16:20 UTC20m
2026-07-12 STT222 - Jul 12, 01:05 UTCJul 12, 02:01 UTC55m
2026-07-11 STT218 - Jul 11, 23:15 UTCJul 12, 00:20 UTC1h 5m
2026-07-11 STT214 - Jul 11, 21:05 UTCJul 11, 22:10 UTC1h 5m
2026-07-11 STT311 - Jul 11, 20:05 UTCJul 11, 20:25 UTC20m
2026-07-11 STT210 - Jul 11, 18:55 UTCJul 11, 19:15 UTC20m
2026-07-11 STT329 LNY → HNL Jul 11, 05:01 UTCJul 11, 05:20 UTC20m
2026-07-11 STT228 - Jul 11, 04:10 UTCJul 11, 04:30 UTC20m
2026-07-11 STT325 - Jul 11, 02:20 UTCJul 11, 03:30 UTC1h 10m
2026-07-11 STT220 - Jul 11, 00:30 UTCJul 11, 01:35 UTC1h 5m
2026-07-10 STT216 - Jul 10, 22:05 UTCJul 10, 23:10 UTC1h 5m
2026-07-10 STT690 - Jul 10, 20:10 UTCJul 10, 21:20 UTC1h 10m
2026-07-10 STT309 - Jul 10, 19:05 UTCJul 10, 19:25 UTC20m
2026-07-10 STT208 - Jul 10, 18:05 UTCJul 10, 18:20 UTC15m
2026-07-10 STT305 - Jul 10, 16:55 UTCJul 10, 17:15 UTC20m
2026-07-10 STT204 - Jul 10, 16:00 UTCJul 10, 16:20 UTC20m
2026-07-10 STT930 - Jul 10, 05:55 UTCJul 10, 06:55 UTC1h 0m
2026-07-10 STT329 - Jul 10, 05:00 UTCJul 10, 05:20 UTC20m

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 N399LA page for operator, model, and routing details .

Mode-S A4A533 frequently asked

What is Mode-S code A4A533?
A4A533 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N399LA.
Where is Mode-S A4A533 registered?
Mode-S code A4A533 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 A4A533 broadcasting right now?
No active broadcast right now. Last signal was Jul 18, 02:50 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A4A533, octal 51122463, decimal 10,790,195.
What flights does A4A533 operate?
Mode-S A4A533 has broadcast 20 distinct callsigns, including STT228, STT208, STT204, STT224, STT329.