sensors Mode-S transponder

A68499

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N519TT · operated by SMITH COLIN B

Hex
A68499
Octal
51502231
Decimal
10,912,921
Country
US
Tail
N519TT
No current signal · last broadcast Jul 26, 19:30 UTC
Flights observed
33
Distinct callsigns
1
Country
US
Last broadcast
Jul 26, 19:30 UTC

Last known position

Most recent position reported by Mode-S A68499.

Country allocation

The ICAO 24-bit address A68499 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 1 distinct

Callsign Airline Flights Last seen
N519TT - 33 2026-07-26

Recent flights last 33

DateFlightRouteTakeoffLandingDuration
2026-07-26 N519TT - Jul 26, 18:55 UTCJul 26, 19:30 UTC35m
2026-07-26 N519TT - Jul 26, 17:50 UTCJul 26, 18:15 UTC25m
2026-07-26 N519TT - Jul 26, 14:55 UTCJul 26, 15:10 UTC15m
2026-07-25 N519TT - Jul 25, 22:10 UTCJul 25, 23:05 UTC55m
2026-07-25 N519TT - Jul 25, 14:40 UTCJul 25, 15:20 UTC40m
2026-07-25 N519TT - Jul 25, 00:00 UTCJul 25, 00:20 UTC20m
2026-07-24 N519TT - Jul 24, 18:20 UTCJul 24, 18:40 UTC20m
2026-07-18 N519TT - Jul 18, 02:35 UTCJul 18, 03:05 UTC31m
2026-07-11 N519TT - Jul 11, 00:00 UTCJul 11, 01:00 UTC1h 0m
2026-07-01 N519TT - Jul 1, 14:35 UTCJul 1, 14:45 UTC10m
2026-06-22 N519TT - Jun 22, 20:19 UTCJun 22, 21:35 UTC1h 15m
2026-06-08 N519TT - Jun 8, 03:00 UTCJun 8, 03:20 UTC20m
2026-06-06 N519TT - Jun 6, 23:00 UTCJun 6, 23:30 UTC30m
2026-06-02 N519TT - Jun 2, 02:15 UTCJun 2, 02:40 UTC25m
2026-06-01 N519TT - Jun 1, 21:55 UTCJun 1, 22:05 UTC10m
2026-06-01 N519TT - Jun 1, 20:00 UTCJun 1, 20:20 UTC20m
2026-06-01 N519TT - Jun 1, 15:55 UTCJun 1, 16:30 UTC35m
2026-06-01 N519TT - Jun 1, 02:00 UTCJun 1, 03:00 UTC1h 0m
2026-06-01 N519TT - Jun 1, 00:15 UTCJun 1, 00:40 UTC25m
2026-05-31 N519TT - May 31, 18:40 UTCMay 31, 19:00 UTC20m
2026-05-31 N519TT - May 31, 17:30 UTCMay 31, 18:10 UTC40m
2026-05-31 N519TT - May 31, 16:10 UTCMay 31, 16:30 UTC20m
2026-05-25 N519TT - May 25, 20:34 UTCMay 25, 21:04 UTC30m
2026-05-25 N519TT - May 25, 17:00 UTCMay 25, 19:00 UTC2h 0m
2026-05-25 N519TT - May 25, 15:30 UTCMay 25, 15:40 UTC10m
2026-05-25 N519TT - May 25, 13:45 UTCMay 25, 14:55 UTC1h 10m
2026-05-24 N519TT - May 24, 20:45 UTCMay 24, 21:20 UTC35m
2026-05-24 N519TT - May 24, 18:25 UTCMay 24, 20:10 UTC1h 45m
2026-05-24 N519TT - May 24, 15:35 UTCMay 24, 17:25 UTC1h 50m
2026-05-24 N519TT - May 24, 02:50 UTCMay 24, 03:25 UTC35m
2026-05-19 N519TT - May 19, 00:05 UTCMay 19, 00:45 UTC40m
2026-05-11 N519TT - May 11, 20:00 UTCMay 11, 20:10 UTC10m
2026-05-11 N519TT - May 11, 15:50 UTCMay 11, 15:55 UTC5m

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 N519TT page for operator, model, and routing details .

Mode-S A68499 frequently asked

What is Mode-S code A68499?
A68499 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N519TT.
Where is Mode-S A68499 registered?
Mode-S code A68499 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 A68499 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 19:30 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A68499, octal 51502231, decimal 10,912,921.
What flights does A68499 operate?
Mode-S A68499 has broadcast 1 distinct callsign, including N519TT.