14 CFR § 65.35 - Knowledge requirements.
Each applicant for an air traffic control tower operator certificate must pass a written test on -
(a) The flight rules in part 91 of this chapter:
(b) Airport traffic control procedures, and this subpart:
(c) En route traffic control procedures;
(d) Communications operating procedures;
(e) Flight assistance service;
(f) Air navigation, and aids to air navigation; and
(g) Aviation weather.