[Code of Federal Regulations] [Title 14, Volume 2] [Revised as of January 1, 2008] From the U.S. Government Printing Office via GPO Access [CITE: 14CFR125.143] [Page 992] TITLE 14--AERONAUTICS AND SPACE CHAPTER I--FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PART 125_CERTIFICATION AND OPERATIONS: AIRPLANES HAVING A SEATING CAPACITY OF Subpart E_Special Airworthiness Requirements Sec. 125.143 Firewalls. Each engine, auxiliary power unit, fuel-burning heater, or other item of combusting equipment that is intended for operation in flight must be isolated from the rest of the airplane by means of firewalls or shrouds, or by other equivalent means.