sensors Mode-S transponder

A2CB14

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N27959 · BOEING 787-9 Dreamliner · operated by UNITED AIRLINES INC

Hex
A2CB14
Octal
50545424
Decimal
10,668,820
Country
US
Tail
N27959
Type
B789
Photo of N27959
Broadcasting now · callsign UAL3906 · 41,000 ft
Flights observed
3
Distinct callsigns
1
Country
US
Last broadcast
2d ago

Current position

A2CB14 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A2CB14 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 1 distinct

Callsign Airline Flights Last seen
UAL1227 United Airlines 3 2026-04-13

Recent flights last 3

DateFlightRouteTakeoffLandingDuration
2026-04-13 UAL1227 PHX → IAD Apr 13, 03:55 UTCApr 13, 04:15 UTC20m
2026-04-13 UAL1227 PHX → IAD Apr 13, 00:20 UTCApr 13, 04:15 UTC3h 55m
2026-04-12 UAL1227 PHX → IAD Apr 12, 23:55 UTCApr 13, 03:50 UTC3h 55m

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 N27959 page for operator, model, and routing details .

Mode-S A2CB14 frequently asked

What is Mode-S code A2CB14?
A2CB14 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N27959.
Where is Mode-S A2CB14 registered?
Mode-S code A2CB14 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 A2CB14 broadcasting right now?
Yes. Mode-S A2CB14 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A2CB14, octal 50545424, decimal 10,668,820.
What flights does A2CB14 operate?
Mode-S A2CB14 has broadcast 1 distinct callsign, including UAL1227.