sensors Mode-S transponder

AD9F57

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N977TH · CESSNA 172 Skyhawk · operated by HEAVY METAL AIR LLC

Hex
AD9F57
Octal
53317527
Decimal
11,378,519
Country
US
Tail
N977TH
Type
C172
No current signal · last broadcast 1d ago
Flights observed
7
Distinct callsigns
1
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S AD9F57.

Country allocation

The ICAO 24-bit address AD9F57 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 1 distinct

Callsign Airline Flights Last seen
N977TH - 7 2026-04-13

Recent flights last 7

DateFlightRouteTakeoffLandingDuration
2026-04-13 N977TH - Apr 13, 19:50 UTCApr 13, 21:00 UTC1h 10m
2026-04-13 N977TH HPN → OXC Apr 13, 19:40 UTCApr 13, 20:10 UTC30m
2026-04-13 N977TH - Apr 13, 17:50 UTCApr 13, 18:55 UTC1h 5m
2026-04-13 N977TH - Apr 13, 13:35 UTCApr 13, 15:00 UTC1h 25m
2026-04-13 N977TH - Apr 13, 12:20 UTCApr 13, 12:45 UTC25m
2026-04-13 N977TH - Apr 13, 12:00 UTCApr 13, 12:15 UTC15m
2026-04-12 N977TH - Apr 12, 20:05 UTCApr 12, 20:15 UTC10m

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 N977TH page for operator, model, and routing details .

Mode-S AD9F57 frequently asked

What is Mode-S code AD9F57?
AD9F57 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N977TH.
Where is Mode-S AD9F57 registered?
Mode-S code AD9F57 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 AD9F57 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 AD9F57, octal 53317527, decimal 11,378,519.
What flights does AD9F57 operate?
Mode-S AD9F57 has broadcast 1 distinct callsign, including N977TH.