sensors Mode-S transponder

AA7F01

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N77571 · BOEING 737 MAX 9 · operated by UNITED AIRLINES INC

Hex
AA7F01
Octal
52477401
Decimal
11,173,633
Country
US
Tail
N77571
Type
B39M
Broadcasting now · callsign UAL1933 · 24,575 ft
Flights observed
8
Distinct callsigns
6
Country
US
Last broadcast
13h ago

Current position

AA7F01 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address AA7F01 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 6 distinct

Callsign Airline Flights Last seen
UAL1628 United Airlines 2 2026-04-13
UAL1047 - 2 2026-04-13
UAL2673 United Airlines 1 2026-04-14
UAL1987 United Airlines 1 2026-04-12
UAL1646 - 1 2026-04-12
UAL1462 - 1 2026-04-13

Recent flights last 8

DateFlightRouteTakeoffLandingDuration
2026-04-14 UAL2673 ORD → LGA Apr 14, 10:55 UTCApr 14, 11:05 UTC10m
2026-04-13 UAL1628 MBJ → EWR Apr 13, 19:50 UTCApr 13, 21:35 UTC1h 45m
2026-04-13 UAL1628 MBJ → EWR Apr 13, 18:05 UTCApr 13, 21:29 UTC3h 24m
2026-04-13 UAL1462 - Apr 13, 13:06 UTCApr 13, 16:38 UTC3h 32m
2026-04-13 UAL1047 - Apr 13, 00:20 UTCApr 13, 02:40 UTC2h 20m
2026-04-13 UAL1047 - Apr 13, 00:00 UTCApr 13, 02:40 UTC2h 40m
2026-04-12 UAL1987 EWR → CUN Apr 12, 18:35 UTCApr 12, 20:15 UTC1h 40m
2026-04-12 UAL1646 - Apr 12, 17:15 UTCApr 12, 17:20 UTC5m

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 N77571 page for operator, model, and routing details .

Mode-S AA7F01 frequently asked

What is Mode-S code AA7F01?
AA7F01 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N77571.
Where is Mode-S AA7F01 registered?
Mode-S code AA7F01 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 AA7F01 broadcasting right now?
Yes. Mode-S AA7F01 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AA7F01, octal 52477401, decimal 11,173,633.
What flights does AA7F01 operate?
Mode-S AA7F01 has broadcast 6 distinct callsigns, including UAL1628, UAL1047, UAL2673, UAL1987, UAL1646.