sensors Mode-S transponder

A66A84

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N512SY · EMBRAER ERJ-170-200 (long wing) · operated by SKYWEST AIRLINES INC

Hex
A66A84
Octal
51465204
Decimal
10,906,244
Country
US
Tail
N512SY
Type
E75L
Broadcasting now · callsign SKW6212 · 34,000 ft
Flights observed
10
Distinct callsigns
7
Country
US
Last broadcast
19h ago

Current position

A66A84 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A66A84 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 7 distinct

Callsign Airline Flights Last seen
SKW5011 SkyWest Airlines 3 2026-04-13
SKW6185 - 2 2026-04-13
SKW6411 - 1 2026-04-12
SKW6289 SkyWest Airlines 1 2026-04-14
SKW6214 - 1 2026-04-13
SKW4888 - 1 2026-04-13
SKW4885 - 1 2026-04-13

Recent flights last 10

DateFlightRouteTakeoffLandingDuration
2026-04-14 SKW6289 LAX → SFO Apr 14, 05:15 UTCApr 14, 05:45 UTC30m
2026-04-13 SKW6214 - Apr 13, 23:30 UTCApr 13, 23:40 UTC10m
2026-04-13 SKW6185 - Apr 13, 21:08 UTCApr 13, 22:06 UTC58m
2026-04-13 SKW6185 - Apr 13, 18:35 UTCApr 13, 19:40 UTC1h 5m
2026-04-13 SKW4885 - Apr 13, 16:55 UTCApr 13, 17:20 UTC25m
2026-04-13 SKW4888 - Apr 13, 15:06 UTCApr 13, 15:39 UTC33m
2026-04-13 SKW5011 STS → PHX Apr 13, 00:20 UTCApr 13, 03:45 UTC3h 25m
2026-04-13 SKW5011 STS → PHX Apr 13, 00:05 UTCApr 13, 03:45 UTC3h 40m
2026-04-12 SKW5011 STS → PHX Apr 12, 20:00 UTCApr 12, 20:15 UTC15m
2026-04-12 SKW6411 - Apr 12, 17:50 UTCApr 12, 18:55 UTC1h 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 N512SY page for operator, model, and routing details .

Mode-S A66A84 frequently asked

What is Mode-S code A66A84?
A66A84 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N512SY.
Where is Mode-S A66A84 registered?
Mode-S code A66A84 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 A66A84 broadcasting right now?
Yes. Mode-S A66A84 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A66A84, octal 51465204, decimal 10,906,244.
What flights does A66A84 operate?
Mode-S A66A84 has broadcast 7 distinct callsigns, including SKW5011, SKW6185, SKW6411, SKW6289, SKW6214.