[Code of Federal Regulations]
[Title 14, Volume 1]
[Revised as of January 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 14CFR33.27]

[Page 774-775]
 
                     TITLE 14--AERONAUTICS AND SPACE
 
CHAPTER I--FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION
 
PART 33_AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES--Table of Contents
 
               Subpart B_Design and Construction; General
 
Sec.  33.27  Turbine, compressor, fan, and turbosupercharger rotors.

    (a) Turbine, compressor, fan, and turbosupercharger rotors must have 
sufficient strength to withstand the test conditions specified in 
paragraph (c) of this section.
    (b) The design and functioning of engine control devices, systems, 
and instruments must give reasonable assurance that those engine 
operating limitations that affect turbine, compressor, fan, and 
turbosupercharger rotor structural integrity will not be exceeded in 
service.
    (c) The most critically stressed rotor component (except blades) of 
each turbine, compressor, and fan, including integral drum rotors and 
centrifugal compressors in an engine or turbosupercharger, as determined 
by analysis or other acceptable means, must be tested for a period of 5 
minutes--
    (1) At its maximum operating temperature, except as provided in 
paragraph (c)(2)(iv) of this section; and
    (2) At the highest speed of the following, as applicable:
    (i) 120 percent of its maximum permissible r.p.m. if tested on a rig 
and equipped with blades or blade weights.
    (ii) 115 percent of its maximum permissible r.p.m. if tested on an 
engine.
    (iii) 115 percent of its maximum permissible r.p.m. if tested on 
turbosupercharger driven by a hot gas supply from a special burner rig.
    (iv) 120 percent of the r.p.m. at which, while cold spinning, it is 
subject to operating stresses that are equivalent to those induced at 
the maximum operating temperature and maximum permissible r.p.m.

[[Page 775]]

    (v) 105 percent of the highest speed that would result from failure 
of the most critical component or system in a representative 
installation of the engine.
    (vi) The highest speed that would result from the failure of any 
component or system in a representative installation of the engine, in 
combination with any failure of a component or system that would not 
normally be detected during a routine preflight check or during normal 
flight operation.

Following the test, each rotor must be within approved dimensional 
limits for an overspeed condition and may not be cracked.

[Amdt. 33-10, 49 FR 6851, Feb. 23, 1984]