1. Quasi-readiness level: able to have simple English conversation, such as communicating with controllers in English in an emergency.
2. Preparation level: able to conduct general English conversation, such as pre-flight and post-flight meetings, simple technical exchanges, emergency troubleshooting, etc.
3. Quasi-operational level: able to conduct general English conversation, such as English communication with controllers, dispatchers and crew members during flight operation, and English communication between studio and crew members.
4. Operational level: able to have basic English conversation, such as communicating with foreign crew members independently in English during flight operation and handling emergencies independently.
5. Extended level: be able to have proficient English conversation, such as communicating with foreign crew members in English and receiving foreign crew members during flight operations.
6. Expert level: be able to have skilled English conversation, such as technical exchange with foreign crew members and reading English materials during flight operation.
I hope the above information will be helpful to you, and the specific classification criteria need to refer to official documents.