[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: 14CFR23.21]

[Page 184-185]
 
                     TITLE 14--AERONAUTICS AND SPACE
 
CHAPTER I--FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION
 
PART 23_AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND 
COMMUTER CATEGORY AIRPLANES--Table of Contents
 
                            Subpart B_Flight
 
Sec.  23.21  Proof of compliance.


                                 General


    (a) Each requirement of this subpart must be met at each appropriate 
combination of weight and center of gravity within the range of loading 
conditions for which certification is requested. This must be shown--

[[Page 185]]

    (1) By tests upon an airplane of the type for which certification is 
requested, or by calculations based on, and equal in accuracy to, the 
results of testing; and
    (2) By systematic investigation of each probable combination of 
weight and center of gravity, if compliance cannot be reasonably 
inferred from combinations investigated.
    (b) The following general tolerances are allowed during flight 
testing. However, greater tolerances may be allowed in particular tests:

------------------------------------------------------------------------
                   Item                               Tolerance
------------------------------------------------------------------------
Weight....................................  +5%, -10%.
Critical items affected by weight.........  +5%, -1%.
C.G.......................................  7%
                                             total travel.
------------------------------------------------------------------------