sensors Mode-S transponder

A20621

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N22995 · BOEING 787-9 Dreamliner · operated by UNITED AIRLINES INC

Hex
A20621
Octal
50403041
Decimal
10,618,401
Country
US
Tail
N22995
Type
B789
Broadcasting now · callsign UAL806 · 10,325 ft
Flights observed
8
Distinct callsigns
3
Country
US
Last broadcast
19h ago

Current position

A20621 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A20621 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 3 distinct

Callsign Airline Flights Last seen
UAL893 United Airlines 4 2026-04-13
UAL892 - 3 2026-04-13
UAL805 - 1 2026-04-14

Recent flights last 8

DateFlightRouteTakeoffLandingDuration
2026-04-14 UAL805 - Apr 14, 07:21 UTCApr 14, 19:27 UTC12h 6m
2026-04-13 UAL892 - Apr 13, 16:55 UTCApr 13, 18:20 UTC1h 25m
2026-04-13 UAL892 - Apr 13, 08:16 UTCApr 13, 18:04 UTC9h 48m
2026-04-13 UAL892 - Apr 13, 08:20 UTCApr 13, 09:50 UTC1h 30m
2026-04-13 UAL893 SFO → ICN Apr 13, 04:20 UTCApr 13, 06:05 UTC1h 45m
2026-04-13 UAL893 SFO → ICN Apr 13, 03:55 UTCApr 13, 06:05 UTC2h 10m
2026-04-13 UAL893 SFO → ICN Apr 13, 03:40 UTCApr 13, 04:15 UTC35m
2026-04-12 UAL893 SFO → ICN Apr 12, 17:50 UTCApr 13, 06:06 UTC12h 16m

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 N22995 page for operator, model, and routing details .

Mode-S A20621 frequently asked

What is Mode-S code A20621?
A20621 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N22995.
Where is Mode-S A20621 registered?
Mode-S code A20621 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 A20621 broadcasting right now?
Yes. Mode-S A20621 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A20621, octal 50403041, decimal 10,618,401.
What flights does A20621 operate?
Mode-S A20621 has broadcast 3 distinct callsigns, including UAL893, UAL892, UAL805.