Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

A4C9D5

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N4076J · AIRBUS A-321neo · operated by JETBLUE AIRWAYS CORP

Hex
A4C9D5
Octal
51144725
Decimal
10,799,573
Country
US
Tail
N4076J
Type
A21N
Transponder active on ground
Flights observed
9
Distinct callsigns
4
Country
US
Last broadcast
12h ago

Last known position

Most recent position reported by Mode-S A4C9D5.

Country allocation

The ICAO 24-bit address A4C9D5 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
JBU34 - 4 2026-04-13
JBU1407 JetBlue Airways 3 2026-04-13
JBU32 JetBlue Airways 1 2026-04-14
JBU31 JetBlue Airways 1 2026-04-14

Recent flights last 9

DateFlightRouteTakeoffLandingDuration
2026-04-14 JBU32 AMS → BOS Apr 14, 09:35 UTCApr 14, 11:05 UTC1h 30m
2026-04-14 JBU31 BOS → AMS Apr 14, 05:15 UTCApr 14, 06:50 UTC1h 35m
2026-04-13 JBU34 - Apr 13, 16:15 UTCApr 13, 17:05 UTC50m
2026-04-13 JBU34 - Apr 13, 15:50 UTCApr 13, 17:05 UTC1h 15m
2026-04-13 JBU34 - Apr 13, 15:40 UTCApr 13, 16:15 UTC35m
2026-04-13 JBU34 - Apr 13, 09:30 UTCApr 13, 11:20 UTC1h 50m
2026-04-13 JBU1407 JFK → CDG Apr 13, 05:00 UTCApr 13, 06:30 UTC1h 30m
2026-04-13 JBU1407 JFK → CDG Apr 13, 00:20 UTCApr 13, 01:40 UTC1h 20m
2026-04-12 JBU1407 JFK → CDG Apr 12, 23:55 UTCApr 13, 01:40 UTC1h 45m

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 N4076J page for operator, model, and routing details .

Mode-S A4C9D5 frequently asked

What is Mode-S code A4C9D5?
A4C9D5 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N4076J.
Where is Mode-S A4C9D5 registered?
Mode-S code A4C9D5 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 A4C9D5 broadcasting right now?
Mode-S A4C9D5 is currently broadcasting from the ground.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A4C9D5, octal 51144725, decimal 10,799,573.
What flights does A4C9D5 operate?
Mode-S A4C9D5 has broadcast 4 distinct callsigns, including JBU34, JBU1407, JBU32, JBU31.