sensors Mode-S transponder

AA7AA0

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N77426 · BOEING 737 MAX 9 · operated by UNITED AIRLINES INC

Hex
AA7AA0
Octal
52475240
Decimal
11,172,512
Country
US
Tail
N77426
Type
B39M
No current signal · last broadcast 1d ago
Flights observed
12
Distinct callsigns
4
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S AA7AA0.

Country allocation

The ICAO 24-bit address AA7AA0 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
UAL639 United Airlines 4 2026-04-13
UAL635 - 4 2026-04-13
UAL418 - 3 2026-04-13
UAL2647 United Airlines 1 2026-04-12

Recent flights last 12

DateFlightRouteTakeoffLandingDuration
2026-04-13 UAL635 - Apr 13, 21:24 UTCApr 14, 02:53 UTC5h 29m
2026-04-13 UAL635 - Apr 13, 16:15 UTCApr 13, 19:05 UTC2h 50m
2026-04-13 UAL635 - Apr 13, 15:50 UTCApr 13, 19:05 UTC3h 15m
2026-04-13 UAL635 - Apr 13, 13:44 UTCApr 13, 19:05 UTC5h 21m
2026-04-13 UAL418 - Apr 13, 08:20 UTCApr 13, 10:55 UTC2h 35m
2026-04-13 UAL418 - Apr 13, 07:55 UTCApr 13, 10:55 UTC3h 0m
2026-04-13 UAL418 - Apr 13, 06:38 UTCApr 13, 10:57 UTC4h 19m
2026-04-13 UAL639 DEN → MSO Apr 13, 04:20 UTCApr 13, 04:40 UTC20m
2026-04-13 UAL639 DEN → MSO Apr 13, 03:55 UTCApr 13, 04:40 UTC45m
2026-04-13 UAL639 DEN → MSO Apr 13, 00:20 UTCApr 13, 04:15 UTC3h 55m
2026-04-12 UAL639 DEN → MSO Apr 12, 23:55 UTCApr 13, 03:50 UTC3h 55m
2026-04-12 UAL2647 DCA → IAH Apr 12, 17:15 UTCApr 12, 20:15 UTC3h 0m

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 N77426 page for operator, model, and routing details .

Mode-S AA7AA0 frequently asked

What is Mode-S code AA7AA0?
AA7AA0 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N77426.
Where is Mode-S AA7AA0 registered?
Mode-S code AA7AA0 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 AA7AA0 broadcasting right now?
No active broadcast right now. Last signal was 1d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AA7AA0, octal 52475240, decimal 11,172,512.
What flights does AA7AA0 operate?
Mode-S AA7AA0 has broadcast 4 distinct callsigns, including UAL639, UAL635, UAL418, UAL2647.