Apparatus

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sensors Mode-S transponder

AC8A5A

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N907NA · NORTHROP T-38 Talon · operated by NATIONAL AERONAUTICS AND SPACE ADMINISTRATION

Hex
AC8A5A
Octal
53105132
Decimal
11,307,610
Country
US
Tail
N907NA
Type
T38
No current signal · last broadcast 1d ago
Flights observed
8
Distinct callsigns
1
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S AC8A5A.

Country allocation

The ICAO 24-bit address AC8A5A 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
N907NA - 8 2026-04-13

Recent flights last 8

DateFlightRouteTakeoffLandingDuration
2026-04-13 N907NA - Apr 13, 22:50 UTCApr 13, 23:35 UTC45m
2026-04-13 N907NA - Apr 13, 21:10 UTCApr 13, 22:20 UTC1h 10m
2026-04-13 N907NA - Apr 13, 19:50 UTCApr 13, 20:15 UTC25m
2026-04-13 N907NA - Apr 13, 19:05 UTCApr 13, 20:10 UTC1h 5m
2026-04-13 N907NA - Apr 13, 16:15 UTCApr 13, 16:50 UTC35m
2026-04-13 N907NA - Apr 13, 15:50 UTCApr 13, 16:50 UTC1h 0m
2026-04-13 N907NA - Apr 13, 15:25 UTCApr 13, 16:15 UTC50m
2026-04-13 N907NA - Apr 13, 13:15 UTCApr 13, 14:30 UTC1h 15m

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 N907NA page for operator, model, and routing details .

Mode-S AC8A5A frequently asked

What is Mode-S code AC8A5A?
AC8A5A is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N907NA.
Where is Mode-S AC8A5A registered?
Mode-S code AC8A5A 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 AC8A5A 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 AC8A5A, octal 53105132, decimal 11,307,610.
What flights does AC8A5A operate?
Mode-S AC8A5A has broadcast 1 distinct callsign, including N907NA.