sensors Mode-S transponder

AA55BD

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N765ST · operated by AMERICAN AIRLINES INC

Hex
AA55BD
Octal
52452675
Decimal
11,163,069
Country
US
Tail
N765ST
Type
E170
No current signal · last broadcast 19h ago
Flights observed
8
Distinct callsigns
5
Country
US
Last broadcast
19h ago

Last known position

Most recent position reported by Mode-S AA55BD.

Country allocation

The ICAO 24-bit address AA55BD 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 5 distinct

Callsign Airline Flights Last seen
ENY4185 - 3 2026-04-13
ENY3655 Envoy Air 2 2026-04-13
ENY9874 - 1 2026-04-14
ENY3886 Envoy Air 1 2026-04-12
ENY3728 - 1 2026-04-13

Recent flights last 8

DateFlightRouteTakeoffLandingDuration
2026-04-14 ENY9874 - Apr 14, 05:15 UTCApr 14, 05:40 UTC25m
2026-04-13 ENY3655 ZIH → DFW Apr 13, 22:15 UTCApr 13, 23:35 UTC1h 20m
2026-04-13 ENY3728 - Apr 13, 19:50 UTCApr 13, 20:50 UTC1h 0m
2026-04-13 ENY4185 - Apr 13, 16:15 UTCApr 13, 20:10 UTC3h 55m
2026-04-13 ENY4185 - Apr 13, 15:50 UTCApr 13, 19:45 UTC3h 55m
2026-04-13 ENY4185 - Apr 13, 15:35 UTCApr 13, 16:15 UTC40m
2026-04-13 ENY3655 ZIH → DFW Apr 13, 00:50 UTCApr 13, 02:30 UTC1h 40m
2026-04-12 ENY3886 CLT → CVG Apr 12, 17:55 UTCApr 12, 18:55 UTC1h 0m

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 N765ST page for operator, model, and routing details .

Mode-S AA55BD frequently asked

What is Mode-S code AA55BD?
AA55BD is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N765ST.
Where is Mode-S AA55BD registered?
Mode-S code AA55BD 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 AA55BD broadcasting right now?
No active broadcast right now. Last signal was 19h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AA55BD, octal 52452675, decimal 11,163,069.
What flights does AA55BD operate?
Mode-S AA55BD has broadcast 5 distinct callsigns, including ENY4185, ENY3655, ENY9874, ENY3886, ENY3728.