There must be enough clearance between the rotor blades and other parts of the structure to prevent the blades from striking any part of the structure during any operating condition.
[Amdt. 29-3, 33 FR 967, Jan. 26, 1968]
source: Docket No. 5084, 29 FR 16150, Dec. 3, 1964, unless otherwise noted.
cite as: 14 CFR 29.661