[Code of Federal Regulations] [Title 14, Volume 1] [Revised as of January 1, 2006] From the U.S. Government Printing Office via GPO Access [CITE: 14CFR33.33] [Page 772] TITLE 14--AERONAUTICS AND SPACE CHAPTER I--FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PART 33_AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES--Table of Contents Subpart C_Design and Construction; Reciprocating Aircraft Engines Sec. 33.33 Vibration. The engine must be designed and constructed to function throughout its normal operating range of crankshaft rotational speeds and engine powers without inducing excessive stress in any of the engine parts because of vibration and without imparting excessive vibration forces to the aircraft structure.