Are airspace violations (e.g. entry to class B without clearance) based on primary radar and/or Mode C transponder, or something else?
I read that Mode C altitude is based on pressure altitude, i.e., set to 29.92" ... but presumably that's adjusted at the ATC facility based on the current pressure before being used for altitude enforcement.
This begs the question, what would stop one (hypothetically), just winding back the altimeter pressure reading to appear to be at a lower altitude?
So to summarize: How are airspace violations detected:
- What data input is used?
- If Mode C reading is used, is it based on pilot's altimeter?
- Would winding back the altimeter make a plane report a lower altitude?