14 CFR 91.173 : Aeronautics And Space (§ 1.1 To Parts 1311-1399) — (§ 60.1 To Parts 108-109) — Federal Aviation Administration, Department Of Transportation (Continued) (§ 60.1 To Parts 108-109) — Air Traffic And General Operating Rules (§ 91.1 To Parts 108-109) — General Operating And Flight Rules (§ 91.1 To Appendix G To Part 91) — Flight Rules (§ 91.101 To §§ 91.195-91.199) — Instrument Flight Rules (§ 91.167 To §§ 91.195-91.199) — ATC clearance and flight plan required.