sensors Mode-S transponder

A4C164

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N405YK · BOEING 737-400 · operated by NAS AIRCRAFT LEASING COMPANY LLC

Hex
A4C164
Octal
51140544
Decimal
10,797,412
Country
US
Tail
N405YK
Type
B734
Broadcasting now · callsign AAH55 · 21,300 ft
Flights observed
8
Distinct callsigns
8
Country
US
Last broadcast
20h ago

Current position

A4C164 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A4C164 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
AAH551 - 1 2026-04-13
AAH550 Aloha Air Cargo 1 2026-04-13
AAH221 - 1 2026-04-14
AAH220 Aloha Air Cargo 1 2026-04-14
AAH18 - 1 2026-04-13
AAH17 - 1 2026-04-13
AAH16 - 1 2026-04-13
AAH15 - 1 2026-04-13

Recent flights last 8

DateFlightRouteTakeoffLandingDuration
2026-04-14 AAH221 - Apr 14, 07:55 UTCApr 14, 08:15 UTC20m
2026-04-14 AAH220 HNL → OGG Apr 14, 06:55 UTCApr 14, 07:10 UTC15m
2026-04-13 AAH18 - Apr 13, 17:15 UTCApr 13, 17:25 UTC10m
2026-04-13 AAH17 - Apr 13, 16:05 UTCApr 13, 16:15 UTC10m
2026-04-13 AAH16 - Apr 13, 14:45 UTCApr 13, 14:55 UTC10m
2026-04-13 AAH15 - Apr 13, 13:15 UTCApr 13, 13:25 UTC10m
2026-04-13 AAH551 - Apr 13, 11:20 UTCApr 13, 11:50 UTC30m
2026-04-13 AAH550 HNL → ITO Apr 13, 09:50 UTCApr 13, 10:10 UTC20m

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 N405YK page for operator, model, and routing details .

Mode-S A4C164 frequently asked

What is Mode-S code A4C164?
A4C164 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N405YK.
Where is Mode-S A4C164 registered?
Mode-S code A4C164 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 A4C164 broadcasting right now?
Yes. Mode-S A4C164 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A4C164, octal 51140544, decimal 10,797,412.
What flights does A4C164 operate?
Mode-S A4C164 has broadcast 8 distinct callsigns, including AAH551, AAH550, AAH221, AAH220, AAH18.