49 CFR § 1552.5

Any individual applying for flight training or recurrent flight training from a flight training provider;

Flight training providers;

Flight training provider employees; and

Persons using a leased aircraft simulator to provide flight training as follows:

If one or more persons using the leased aircraft simulator to provide flight training is certificated by the FAA as a flight instructor, then at least one of those certificated persons must register with TSA as a flight training provider and comply with the requirements of this part; or

If one or more persons using a leased aircraft simulator to provide flight training are neither registered with TSA as a flight training provider nor certificated by the FAA as an instructor, then the lessor of the aircraft simulator must register with TSA as a flight training provider and comply with the requirements of this part.