[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: 14CFR99.27] [Page 297] TITLE 14--AERONAUTICSAND SPACE CHAPTER I--FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PART 99--SECURITY CONTROL OF AIR TRAFFIC--Table of Contents Subpart A--General Sec. 99.27 Deviation from flight plans and ATC clearances and instructions. (a) No pilot may deviate from the provisions of an ATC clearance or ATC instruction except in accordance with Sec. 91.123 of this chapter. (b) No pilot may deviate from the filed IFR flight plan when operating an aircraft in uncontrolled airspace unless that pilot notifies an appropriate aeronautical facility before deviating. (c) No pilot may deviate from the filed DVFR flight plan unless that pilot notifies an appropriate aeronautical facility before deviating. [Doc. No. 25113, 53 FR 18217, May 20, 1988, as amended by Amdt. 99-15, 54 FR 34331, Aug. 18, 1989]