sensors Mode-S transponder

A5DEE3

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N478AS · BOEING 737-900 · operated by ALASKA AIRLINES INC

Hex
A5DEE3
Octal
51357343
Decimal
10,870,499
Country
US
Tail
N478AS
Type
B739
Broadcasting now · callsign ASA1403 · 34,000 ft
Flights observed
8
Distinct callsigns
5
Country
US
Last broadcast
17h ago

Current position

A5DEE3 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A5DEE3 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
ASA714 - 2 2026-04-12
ASA333 Alaska Airlines 2 2026-04-13
ASA294 - 2 2026-04-13
ASA287 Alaska Airlines 1 2026-04-14
ASA207 - 1 2026-04-13

Recent flights last 8

DateFlightRouteTakeoffLandingDuration
2026-04-14 ASA287 EWR → LAX Apr 14, 05:15 UTCApr 14, 05:35 UTC20m
2026-04-13 ASA294 - Apr 13, 19:50 UTCApr 13, 22:25 UTC2h 35m
2026-04-13 ASA294 - Apr 13, 17:45 UTCApr 13, 20:10 UTC2h 25m
2026-04-13 ASA207 - Apr 13, 04:49 UTCApr 13, 06:44 UTC1h 55m
2026-04-13 ASA333 SFO → SEA Apr 13, 00:20 UTCApr 13, 01:00 UTC40m
2026-04-12 ASA333 SFO → SEA Apr 12, 23:55 UTCApr 13, 01:00 UTC1h 5m
2026-04-12 ASA714 - Apr 12, 17:28 UTCApr 12, 21:20 UTC3h 52m
2026-04-12 ASA714 - Apr 12, 17:32 UTCApr 12, 21:22 UTC3h 50m

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 N478AS page for operator, model, and routing details .

Mode-S A5DEE3 frequently asked

What is Mode-S code A5DEE3?
A5DEE3 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N478AS.
Where is Mode-S A5DEE3 registered?
Mode-S code A5DEE3 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 A5DEE3 broadcasting right now?
Yes. Mode-S A5DEE3 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A5DEE3, octal 51357343, decimal 10,870,499.
What flights does A5DEE3 operate?
Mode-S A5DEE3 has broadcast 5 distinct callsigns, including ASA714, ASA333, ASA294, ASA287, ASA207.