sensors Mode-S transponder

A05A49

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N12136 · EMBRAER ERJ-145XR · operated by UNITED AIRLINES INC

Hex
A05A49
Octal
50055111
Decimal
10,508,873
Country
US
Tail
N12136
Type
E45X
No current signal · last broadcast 23h ago
Flights observed
10
Distinct callsigns
7
Country
US
Last broadcast
23h ago

Last known position

Most recent position reported by Mode-S A05A49.

Country allocation

The ICAO 24-bit address A05A49 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
UCA4276 - 3 2026-04-13
UCA4277 CommutAir 2 2026-04-13
UCA5004 CommutAir 1 2026-04-13
UCA4837 - 1 2026-04-13
UCA4376 - 1 2026-04-12
UCA4323 - 1 2026-04-13
UCA4234 CommutAir 1 2026-04-12

Recent flights last 10

DateFlightRouteTakeoffLandingDuration
2026-04-13 UCA4323 - Apr 13, 22:55 UTCApr 13, 23:45 UTC50m
2026-04-13 UCA4277 DEN → XNA Apr 13, 19:50 UTCApr 13, 20:10 UTC20m
2026-04-13 UCA4277 DEN → XNA Apr 13, 18:30 UTCApr 13, 20:10 UTC1h 40m
2026-04-13 UCA4276 - Apr 13, 16:15 UTCApr 13, 17:20 UTC1h 5m
2026-04-13 UCA4276 - Apr 13, 15:50 UTCApr 13, 17:20 UTC1h 30m
2026-04-13 UCA4276 - Apr 13, 15:30 UTCApr 13, 16:15 UTC45m
2026-04-13 UCA4837 - Apr 13, 12:43 UTCApr 13, 13:50 UTC1h 7m
2026-04-13 UCA5004 IAH → MSY Apr 13, 00:40 UTCApr 13, 01:30 UTC50m
2026-04-12 UCA4234 COD → DEN Apr 12, 19:44 UTCApr 12, 20:26 UTC42m
2026-04-12 UCA4376 - Apr 12, 17:15 UTCApr 12, 18:30 UTC1h 15m

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 N12136 page for operator, model, and routing details .

Mode-S A05A49 frequently asked

What is Mode-S code A05A49?
A05A49 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N12136.
Where is Mode-S A05A49 registered?
Mode-S code A05A49 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 A05A49 broadcasting right now?
No active broadcast right now. Last signal was 23h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A05A49, octal 50055111, decimal 10,508,873.
What flights does A05A49 operate?
Mode-S A05A49 has broadcast 7 distinct callsigns, including UCA4276, UCA4277, UCA5004, UCA4837, UCA4376.