The registration of an air taxi operator may be canceled by the Department if any of the following occur:

1. (a) The operator ceases its operations;
2. (b) The operator's insurance coverage changes or lapses;
3. (c) The operator fails to file an amended registration when required by § 298.23;
4. (d) The operator's Air Carrier Certificate and/or Operations Specifications is revoked by the Federal Aviation Administration;
5. (e) The operator fails to qualify as a citizen of the United States;
6. (f) The Department determines that it is otherwise in the public interest to do so.