Asymmetric cryptography isn't a rocket science. Airline keeps encrypted recording and public key, certain government institution keeps private key, you need both to decrypt.
This violates rule 2 by not assuring that a warrant is necessary because somebody at the government institution has the private key (assuming that institution is not the judge): It should be technologically impossible for any person or entity to access the data without a warrant
I don’t understand why you’d impose restrictions on this system that do not exist elsewhere? What makes cockpit voice recordings sensitive enough to warrant more secure storage than people’s bank accounts?