[Code of Federal Regulations] [Title 14, Volume 2] [Revised as of January 1, 2003] From the U.S. Government Printing Office via GPO Access [CITE: 14CFR139.331] [Page 790] TITLE 14--AERONAUTICSAND SPACE CHAPTER I--FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PART 139--CERTIFICATION AND OPERATIONS: LAND AIRPORTS SERVING CERTAIN AIR CARRIERS--Table of Contents Subpart D--Operations Sec. 139.331 Obstructions. Each certificate holder shall ensure that each object in each area within its authority which exceeds any of the heights or penetrates the imaginary surfaces described in part 77 of this chapter is either removed, marked, or lighted. However, removal, marking, and lighting is not required if it is determined to be unnecessary by an FAA aeronautical study.