sensors Mode-S transponder

AA4AC9

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N762US · AIRBUS A-319 · operated by UMB BANK NA TRUSTEE

Hex
AA4AC9
Octal
52445311
Decimal
11,160,265
Country
US
Tail
N762US
Type
A319
Photo of N762US
No current signal · last broadcast 1d ago
Flights observed
15
Distinct callsigns
8
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S AA4AC9.

Country allocation

The ICAO 24-bit address AA4AC9 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 8 distinct

Callsign Airline Flights Last seen
AAL523 - 3 2026-04-13
AAL3110 - 3 2026-04-13
AAL2165 - 3 2026-04-13
AAL2276 American Airlines 2 2026-04-12
AAL443 - 1 2026-04-13
AAL419 - 1 2026-04-13
AAL2869 - 1 2026-04-13
AAL1259 - 1 2026-04-13

Recent flights last 15

DateFlightRouteTakeoffLandingDuration
2026-04-13 AAL419 - Apr 13, 21:36 UTCApr 13, 22:59 UTC1h 23m
2026-04-13 AAL2165 - Apr 13, 19:50 UTCApr 13, 20:05 UTC15m
2026-04-13 AAL2165 - Apr 13, 19:25 UTCApr 13, 20:11 UTC46m
2026-04-13 AAL2165 - Apr 13, 17:25 UTCApr 13, 17:50 UTC25m
2026-04-13 AAL2869 - Apr 13, 14:12 UTCApr 13, 15:17 UTC1h 5m
2026-04-13 AAL523 - Apr 13, 12:20 UTCApr 13, 13:30 UTC1h 10m
2026-04-13 AAL523 - Apr 13, 12:10 UTCApr 13, 13:30 UTC1h 20m
2026-04-13 AAL523 - Apr 13, 11:31 UTCApr 13, 12:58 UTC1h 27m
2026-04-13 AAL1259 - Apr 13, 10:10 UTCApr 13, 11:00 UTC50m
2026-04-13 AAL3110 - Apr 13, 04:20 UTCApr 13, 04:55 UTC35m
2026-04-13 AAL3110 - Apr 13, 03:34 UTCApr 13, 04:35 UTC1h 1m
2026-04-13 AAL3110 - Apr 13, 03:58 UTCApr 13, 04:51 UTC53m
2026-04-13 AAL443 IND → ORD Apr 13, 00:55 UTCApr 13, 01:37 UTC42m
2026-04-12 AAL2276 ORD → EWR Apr 12, 19:23 UTCApr 12, 21:15 UTC1h 52m
2026-04-12 AAL2276 ORD → EWR Apr 12, 17:15 UTCApr 12, 17:20 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 N762US page for operator, model, and routing details .

Mode-S AA4AC9 frequently asked

What is Mode-S code AA4AC9?
AA4AC9 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N762US.
Where is Mode-S AA4AC9 registered?
Mode-S code AA4AC9 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 AA4AC9 broadcasting right now?
No active broadcast right now. Last signal was 1d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AA4AC9, octal 52445311, decimal 11,160,265.
What flights does AA4AC9 operate?
Mode-S AA4AC9 has broadcast 8 distinct callsigns, including AAL523, AAL3110, AAL2165, AAL2276, AAL443.