sensors Mode-S transponder

AAAB1A

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N787FX · operated by FEDERAL EXPRESS CORP

Hex
AAAB1A
Octal
52525432
Decimal
11,184,922
Country
US
Tail
N787FX
No current signal · last broadcast 22d ago
Flights observed
6
Distinct callsigns
4
Country
US
Last broadcast
22d ago

Last known position

Most recent position reported by Mode-S AAAB1A.

Country allocation

The ICAO 24-bit address AAAB1A 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 4 distinct

Callsign Airline Flights Last seen
CSTT133 - 2 2026-06-24
CSTT127 - 2 2026-06-10
N787FX - 1 2026-06-25
CSTT141 - 1 2026-06-11

Recent flights last 6

DateFlightRouteTakeoffLandingDuration
2026-06-25 N787FX BEC → FAR Jun 25, 14:39 UTCJun 25, 17:54 UTC3h 15m
2026-06-24 CSTT133 BEC → BEC Jun 24, 16:24 UTCJun 24, 16:45 UTC20m
2026-06-22 CSTT133 BEC → BEC Jun 22, 14:34 UTCJun 22, 15:54 UTC1h 20m
2026-06-11 CSTT141 BEC → BEC Jun 11, 14:15 UTCJun 11, 14:55 UTC40m
2026-06-10 CSTT127 BEC → BEC Jun 10, 14:10 UTCJun 10, 14:45 UTC35m
2026-06-06 CSTT127 BEC → BEC Jun 6, 15:59 UTCJun 6, 18:04 UTC2h 5m

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 N787FX page for operator, model, and routing details .

Mode-S AAAB1A frequently asked

What is Mode-S code AAAB1A?
AAAB1A is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N787FX.
Where is Mode-S AAAB1A registered?
Mode-S code AAAB1A 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 AAAB1A broadcasting right now?
No active broadcast right now. Last signal was 22d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AAAB1A, octal 52525432, decimal 11,184,922.
What flights does AAAB1A operate?
Mode-S AAAB1A has broadcast 4 distinct callsigns, including CSTT133, CSTT127, N787FX, CSTT141.