sensors Mode-S transponder

A5CF66

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N47357 · BOEING 737 MAX 8 · operated by UNITED AIRLINES INC

Hex
A5CF66
Octal
51347546
Decimal
10,866,534
Country
US
Tail
N47357
Type
B38M
Broadcasting now · callsign UAL1395 · 35,000 ft
Flights observed
8
Distinct callsigns
5
Country
US
Last broadcast
23h ago

Current position

A5CF66 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A5CF66 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
UAL2000 - 3 2026-04-13
UAL2033 United Airlines 2 2026-04-13
UAL8185 - 1 2026-04-13
UAL1588 United Airlines 1 2026-04-13
UAL1584 United Airlines 1 2026-04-12

Recent flights last 8

DateFlightRouteTakeoffLandingDuration
2026-04-13 UAL1588 EWR → SAV Apr 13, 21:05 UTCApr 13, 23:40 UTC2h 35m
2026-04-13 UAL8185 DEN → PNS Apr 13, 17:20 UTCApr 13, 19:40 UTC2h 20m
2026-04-13 UAL2000 - Apr 13, 12:20 UTCApr 13, 15:20 UTC3h 0m
2026-04-13 UAL2000 - Apr 13, 11:55 UTCApr 13, 15:20 UTC3h 25m
2026-04-13 UAL2000 - Apr 13, 11:26 UTCApr 13, 15:17 UTC3h 51m
2026-04-13 UAL2033 RNO → SFO Apr 13, 00:20 UTCApr 13, 02:55 UTC2h 35m
2026-04-12 UAL2033 RNO → SFO Apr 12, 23:55 UTCApr 13, 02:55 UTC3h 0m
2026-04-12 UAL1584 SNA → SFO Apr 12, 17:42 UTCApr 12, 19:16 UTC1h 34m

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 N47357 page for operator, model, and routing details .

Mode-S A5CF66 frequently asked

What is Mode-S code A5CF66?
A5CF66 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N47357.
Where is Mode-S A5CF66 registered?
Mode-S code A5CF66 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 A5CF66 broadcasting right now?
Yes. Mode-S A5CF66 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A5CF66, octal 51347546, decimal 10,866,534.
What flights does A5CF66 operate?
Mode-S A5CF66 has broadcast 5 distinct callsigns, including UAL2000, UAL2033, UAL8185, UAL1588, UAL1584.