sensors Mode-S transponder

AA7F03

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N77573 · BOEING 737 MAX 9 · operated by UNITED AIRLINES INC

Hex
AA7F03
Octal
52477403
Decimal
11,173,635
Country
US
Tail
N77573
Type
B39M
Broadcasting now · callsign UAL3738 · 26,050 ft
Flights observed
6
Distinct callsigns
5
Country
US
Last broadcast
16h ago

Current position

AA7F03 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address AA7F03 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 5 distinct

Callsign Airline Flights Last seen
UAL2031 - 2 2026-04-13
UAL758 - 1 2026-04-13
UAL2005 - 1 2026-04-13
UAL1958 United Airlines 1 2026-04-14
UAL1652 - 1 2026-04-13

Recent flights last 6

DateFlightRouteTakeoffLandingDuration
2026-04-14 UAL1958 RDU → EWR Apr 14, 05:15 UTCApr 14, 06:35 UTC1h 20m
2026-04-13 UAL1652 - Apr 13, 21:36 UTCApr 13, 22:22 UTC46m
2026-04-13 UAL2031 - Apr 13, 19:50 UTCApr 13, 20:15 UTC25m
2026-04-13 UAL2031 - Apr 13, 16:45 UTCApr 13, 20:10 UTC3h 25m
2026-04-13 UAL758 - Apr 13, 13:31 UTCApr 13, 14:30 UTC59m
2026-04-13 UAL2005 - Apr 13, 02:05 UTCApr 13, 03:05 UTC1h 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 N77573 page for operator, model, and routing details .

Mode-S AA7F03 frequently asked

What is Mode-S code AA7F03?
AA7F03 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N77573.
Where is Mode-S AA7F03 registered?
Mode-S code AA7F03 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 AA7F03 broadcasting right now?
Yes. Mode-S AA7F03 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AA7F03, octal 52477403, decimal 11,173,635.
What flights does AA7F03 operate?
Mode-S AA7F03 has broadcast 5 distinct callsigns, including UAL2031, UAL758, UAL2005, UAL1958, UAL1652.