sensors Mode-S transponder

A2B8FE

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N2749U · BOEING 777-300ER · operated by UNITED AIRLINES INC

Hex
A2B8FE
Octal
50534376
Decimal
10,664,190
Country
US
Tail
N2749U
Type
B77W
No current signal · last broadcast 12h ago
Flights observed
6
Distinct callsigns
4
Country
US
Last broadcast
12h ago

Last known position

Most recent position reported by Mode-S A2B8FE.

Country allocation

The ICAO 24-bit address A2B8FE 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 4 distinct

Callsign Airline Flights Last seen
UAL803 United Airlines 3 2026-04-14
UAL876 United Airlines 1 2026-04-14
UAL435 United Airlines 1 2026-04-12
UAL3918 - 1 2026-04-13

Recent flights last 6

DateFlightRouteTakeoffLandingDuration
2026-04-14 UAL876 HND → SFO Apr 14, 09:45 UTCApr 14, 10:20 UTC35m
2026-04-14 UAL803 IAD → HND Apr 14, 05:50 UTCApr 14, 06:35 UTC45m
2026-04-13 UAL803 IAD → HND Apr 13, 23:25 UTCApr 13, 23:40 UTC15m
2026-04-13 UAL803 IAD → HND Apr 13, 16:50 UTCApr 13, 18:10 UTC1h 20m
2026-04-13 UAL3918 EWR → IAD Apr 13, 04:57 UTCApr 13, 05:37 UTC40m
2026-04-12 UAL435 KOA → SFO Apr 12, 17:45 UTCApr 12, 20:15 UTC2h 30m

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 N2749U page for operator, model, and routing details .

Mode-S A2B8FE frequently asked

What is Mode-S code A2B8FE?
A2B8FE is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N2749U.
Where is Mode-S A2B8FE registered?
Mode-S code A2B8FE 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 A2B8FE broadcasting right now?
No active broadcast right now. Last signal was 12h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A2B8FE, octal 50534376, decimal 10,664,190.
What flights does A2B8FE operate?
Mode-S A2B8FE has broadcast 4 distinct callsigns, including UAL803, UAL876, UAL435, UAL3918.