150
14 CFR Ch. I (1–1–24 Edition)
§ 21.95
(ii) Designated for dispensing fire
fighting materials to which § 36.1583 of
this chapter does not apply, or
(iii) U.S. registered, and that had
flight time prior to January 1, 1955 or
(iv) Land configured aircraft recon-
figured with floats or skis. This recon-
figuration does not permit further ex-
ception from the requirements of this
section upon any acoustical change not
enumerated in § 21.93(b).
(4) Helicopters except:
(i) Those helicopters that are des-
ignated exclusively:
(A) For ‘‘agricultural aircraft oper-
ations’’, as defined in § 137.3 of this
chapter, as effective on January 1, 1966;
(B) For dispensing fire fighting mate-
rials; or
(C) For carrying external loads, as
defined in § 133.1(b) of this chapter, as
effective on December 20, 1976.
(ii) Those helicopters modified by in-
stallation or removal of external equip-
ment. For purposes of this paragraph,
‘‘external equipment’’ means any in-
strument, mechanism, part, apparatus,
appurtenance, or accessory that is at-
tached to, or extends from, the heli-
copter exterior but is not used nor is
intended to be used in operating or
controlling a helicopter in flight and is
not part of an airframe or engine. An
‘‘acoustical change’’ does not include:
(A) Addition or removal of external
equipment;
(B) Changes in the airframe made to
accommodate the addition or removal
of external equipment, to provide for
an external load attaching means, to
facilitate the use of external equip-
ment or external loads, or to facilitate
the safe operation of the helicopter
with external equipment mounted to,
or external loads carried by, the heli-
copter;
(C) Reconfiguration of the helicopter
by the addition or removal of floats
and skis;
(D) Flight with one or more doors
and/or windows removed or in an open
position; or
(E) Any changes in the operational
limitations placed on the helicopter as
a consequence of the addition or re-
moval of external equipment, floats,
and skis, or flight operations with
doors and/or windows removed or in an
open position.
(5) Tiltrotors.
(c) For purposes of complying with
part 34 of this chapter, any voluntary
change in the type design of the air-
plane or engine which may increase
fuel venting or exhaust emissions is an
‘‘emissions change.’’
[Amdt. 21–27, 34 FR 18363, Nov. 18, 1969]
E
DITORIAL
N
OTE
: For F
EDERAL
R
EGISTER
ci-
tations affecting § 21.93, see the List of CFR
Sections Affected, which appears in the
Finding Aids section of the printed volume
and at
www.govinfo.gov.
§ 21.95
Approval of minor changes in
type design.
Minor changes in a type design may
be approved under a method acceptable
to the FAA before submitting to the
FAA any substantiating or descriptive
data.
§ 21.97
Approval of major changes in
type design.
(a) An applicant for approval of a
major change in type design must—
(1) Provide substantiating data and
necessary descriptive data for inclu-
sion in the type design;
(2) Show that the change and areas
affected by the change comply with the
applicable requirements of this sub-
chapter, and provide the FAA the
means by which such compliance has
been shown; and
(3) Provide a statement certifying
that the applicant has complied with
the applicable requirements.
(b) Approval of a major change in the
type design of an aircraft engine is lim-
ited to the specific engine configura-
tion upon which the change is made
unless the applicant identifies in the
necessary descriptive data for inclu-
sion in the type design the other con-
figurations of the same engine type for
which approval is requested and shows
that the change is compatible with the
other configurations.
[Amdt. 21–40, 39 FR 35459, Oct. 1, 1974, as
amended by Amdt. 21–92, 74 FR 53387, Oct. 16,
2009; Amdt. 21–96, 77 FR 71695, Dec. 4, 2012]
§ 21.99
Required design changes.
(a) When an Airworthiness Directive
is issued under Part 39 the holder of
the type certificate for the product
concerned must—
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