CFR > Title 14 - Aeronautics and Space > CHAPTER I—FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION > SUBCHAPTER F—AIR TRAFFIC AND GENERAL OPERATING RULES (parts 91 to 106) > PART 91—GENERAL OPERATING AND FLIGHT RULES > SUBPART B—Flight Rules (§91.101 to §91.195-91.199) > 91.159—VFR cruising altitude or flight level.

91.159—VFR cruising altitude or flight level.

Except while holding in a holding pattern of 2 minutes or less, or while turning, each person operating an aircraft under VFR in level cruising flight more than 3,000 feet above the surface shall maintain the appropriate altitude or flight level prescribed below, unless otherwise authorized by ATC:
(a) When operating below 18,000 feet MSL and—
(1) On a magnetic course of zero degrees through 179 degrees, any odd thousand foot MSL altitude 500 feet (such as 3,500, 5,500, or 7,500); or
(2) On a magnetic course of 180 degrees through 359 degrees, any even thousand foot MSL altitude 500 feet (such as 4,500, 6,500, or 8,500).
(b) When operating above 18,000 feet MSL, maintain the altitude or flight level assigned by ATC.

Code of Federal Regulations

[Doc. No. 18334, 54 FR 34294, Aug. 18, 1989, as amended by Amdt. 91-276, 68 FR 61321, Oct. 27, 2003; 68 FR 70133, Dec. 17, 2003]