sensors Mode-S transponder

A254DA

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N24976 · BOEING 787-9 Dreamliner · operated by UNITED AIRLINES INC

Hex
A254DA
Octal
50452332
Decimal
10,638,554
Country
US
Tail
N24976
Type
B789
No current signal · last broadcast 13h ago
Flights observed
8
Distinct callsigns
4
Country
US
Last broadcast
13h ago

Last known position

Most recent position reported by Mode-S A254DA.

Country allocation

The ICAO 24-bit address A254DA 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
UAL893 United Airlines 2 2026-04-14
UAL892 - 2 2026-04-14
UAL115 United Airlines 2 2026-04-13
UAL114 - 2 2026-04-13

Recent flights last 8

DateFlightRouteTakeoffLandingDuration
2026-04-14 UAL892 - Apr 14, 09:20 UTCApr 14, 10:00 UTC40m
2026-04-14 UAL892 - Apr 14, 08:16 UTCApr 14, 18:09 UTC9h 53m
2026-04-14 UAL893 SFO → ICN Apr 14, 05:15 UTCApr 14, 05:45 UTC30m
2026-04-13 UAL893 SFO → ICN Apr 13, 17:55 UTCApr 13, 18:20 UTC25m
2026-04-13 UAL114 - Apr 13, 14:25 UTCApr 13, 14:55 UTC30m
2026-04-13 UAL114 - Apr 13, 07:05 UTCApr 13, 07:45 UTC40m
2026-04-13 UAL115 SFO → PPT Apr 13, 04:20 UTCApr 13, 04:50 UTC30m
2026-04-13 UAL115 SFO → PPT Apr 13, 04:00 UTCApr 13, 04:15 UTC15m

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 N24976 page for operator, model, and routing details .

Mode-S A254DA frequently asked

What is Mode-S code A254DA?
A254DA is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N24976.
Where is Mode-S A254DA registered?
Mode-S code A254DA 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 A254DA broadcasting right now?
No active broadcast right now. Last signal was 13h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A254DA, octal 50452332, decimal 10,638,554.
What flights does A254DA operate?
Mode-S A254DA has broadcast 4 distinct callsigns, including UAL893, UAL892, UAL115, UAL114.