[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: 14CFR21.101]

[Page 136-138]
 
                     TITLE 14--AERONAUTICS AND SPACE
 
CHAPTER I--FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION
 
PART 21_CERTIFICATION PROCEDURES FOR PRODUCTS AND PARTS--Table of 
Contents
 
                 Subpart D_Changes to Type Certificates
 
Sec.  21.101  Designation of applicable regulations.

    (a) An applicant for a change to a type certificate must show that 
the changed product complies with the airworthiness requirements 
applicable to

[[Page 137]]

the category of the product in effect on the date of the application for 
the change and with parts 34 and 36 of this chapter. Exceptions are 
detailed in paragraphs (b) and (c) of this section.
    (b) If paragraphs (b)(1), (2), or (3) of this section apply, an 
applicant may show that the changed product complies with an earlier 
amendment of a regulation required by paragraph (a) of this section, and 
of any other regulation the Administrator finds is directly related. 
However, the earlier amended regulation may not precede either the 
corresponding regulation incorporated by reference in the type 
certificate, or any regulation in Sec.  Sec.  23.2, 25.2, 27.2, or 29.2 
of this chapter that is related to the change. The applicant may show 
compliance with an earlier amendment of a regulation for any of the 
following:
    (1) A change that the Administrator finds not to be significant. In 
determining whether a specific change is significant, the Administrator 
considers the change in context with all previous relevant design 
changes and all related revisions to the applicable regulations 
incorporated in the type certificate for the product. Changes that meet 
one of the following criteria are automatically considered significant:
    (i) The general configuration or the principles of construction are 
not retained.
    (ii) The assumptions used for certification of the product to be 
changed do not remain valid.
    (2) Each area, system, component, equipment, or appliance that the 
Administrator finds is not affected by the change.
    (3) Each area, system, component, equipment, or appliance that is 
affected by the change, for which the Administrator finds that 
compliance with a regulation described in paragraph (a) of this section 
would not contribute materially to the level of safety of the changed 
product or would be impractical.
    (c) An applicant for a change to an aircraft (other than a 
rotorcraft) of 6,000 pounds or less maximum weight, or to a non-turbine 
rotorcraft of 3,000 pounds or less maximum weight may show that the 
changed product complies with the regulations incorporated by reference 
in the type certificate. However, if the Administrator finds that the 
change is significant in an area, the Administrator may designate 
compliance with an amendment to the regulation incorporated by reference 
in the type certificate that applies to the change and any regulation 
that the Administrator finds is directly related, unless the 
Administrator also finds that compliance with that amendment or 
regulation would not contribute materially to the level of safety of the 
changed product or would be impractical.
    (d) If the Administrator finds that the regulations in effect on the 
date of the application for the change do not provide adequate standards 
with respect to the proposed change because of a novel or unusual design 
feature, the applicant must also comply with special conditions, and 
amendments to those special conditions, prescribed under the provisions 
of Sec.  21.16, to provide a level of safety equal to that established 
by the regulations in effect on the date of the application for the 
change.
    (e) An application for a change to a type certificate for a 
transport category aircraft is effective for 5 years, and an application 
for a change to any other type certificate is effective for 3 years. If 
the change has not been approved, or if it is clear that it will not be 
approved under the time limit established under this paragraph, the 
applicant may do either of the following:
    (1) File a new application for a change to the type certificate and 
comply with all the provisions of paragraph (a) of this section 
applicable to an original application for a change.
    (2) File for an extension of the original application and comply 
with the provisions of paragraph (a) of this section. The applicant must 
then select a new application date. The new application date may not 
precede the date the change is approved by more than the time period 
established under this paragraph (e).
    (f) For aircraft certificated under Sec.  Sec.  21.17(b), 21.24, 
21.25, and 21.27 the airworthiness requirements applicable to the 
category of the product in effect on the date of the application for the

[[Page 138]]

change include each airworthiness requirement that the Administrator 
finds to be appropriate for the type certification of the aircraft in 
accordance with those sections.

[Doc. No. 28903, 65 FR 36266, June 7, 2000]