title-14-part-27-sec27-1043

540

14 CFR Ch. I (1–1–24 Edition)

§ 27.1027

(b) Have manual or automatic means

for positive locking in the closed posi-
tion.

[Amdt. 27–20, 49 FR 6849, Feb. 23, 1984]

§ 27.1027

Transmissions and gear-

boxes: General.

(a) The lubrication system for com-

ponents of the rotor drive system that
require continuous lubrication must be
sufficiently independent of the lubrica-
tion systems of the engine(s) to ensure
lubrication during autorotation.

(b) Pressure lubrication systems for

transmissions and gearboxes must
comply with the engine oil system re-
quirements of §§ 27.1013 (except para-
graph (c)), 27.1015, 27.1017, 27.1021, and
27.1337(d).

must have an oil strainer or filter
through which all of the lubricant
flows and must—

(1) Be designed to remove from the

lubricant any contaminant which may
damage transmission and drive system
components or impede the flow of lu-
bricant to a hazardous degree;

(2) Be equipped with a means to indi-

cate collection of contaminants on the
filter or strainer at or before opening
of the bypass required by paragraph
(c)(3) of this section; and

(3) Be equipped with a bypass con-

structed and installed so that—

(i) The lubricant will flow at the nor-

mal rate through the rest of the sys-
tem with the strainer or filter com-
pletely blocked; and

(ii) The release of collected contami-

nants is minimized by appropriate lo-
cation of the bypass to ensure that col-
lected contaminants are not in the by-
pass flowpath.

(d) For each lubricant tank or sump

outlet supplying lubrication to rotor
drive systems and rotor drive system
components, a screen must be provided
to prevent entrance into the lubrica-
tion system of any object that might
obstruct the flow of lubricant from the
outlet to the filter required by para-
graph (c) of this section. The require-
ments of paragraph (c) do not apply to
screens installed at lubricant tank or
sump outlets.

(e) Splash-type lubrication systems

for rotor drive system gearboxes must
comply with §§ 27.1021 and 27.1337(d).

[Amdt. 27–23, 53 FR 34213, Sept. 2, 1988, as
amended by Amdt. 27–37, 64 FR 45095, Aug. 18,
1999]

OOLING

§ 27.1041

General.

(a) Each powerplant cooling system

must be able to maintain the tempera-
tures of powerplant components within
the limits established for these compo-
nents under critical surface (ground or
water) and flight operating conditions
for which certification is required and
after normal shutdown. Powerplant
components to be considered include
but may not be limited to engines,
rotor drive system components, auxil-
iary power units, and the cooling or lu-
bricating fluids used with these compo-
nents.

(b) Compliance with paragraph (a) of

this section must be shown in tests
conducted under the conditions pre-
scribed in that paragraph.

[Doc. No. 5074, 29 FR 15695, Nov. 24, 1964, as
amended by Amdt. 27–23, 53 FR 34213, Sept. 2,
1988]

§ 27.1043

Cooling tests.

(a)

General. For the tests prescribed

in § 27.1041(b), the following apply:

(1) If the tests are conducted under

conditions deviating from the max-
imum ambient atmospheric tempera-
ture specified in paragraph (b) of this
section, the recorded powerplant tem-
peratures must be corrected under
paragraphs (c) and (d) of this section
unless a more rational correction
method is applicable.

(2) No corrected temperature deter-

mined under paragraph (a)(1) of this
section may exceed established limits.

(3) For reciprocating engines, the fuel

used during the cooling tests must be
of the minimum grade approved for the
engines, and the mixture settings must
be those normally used in the flight
stages for which the cooling tests are
conducted.

(4) The test procedures must be as

prescribed in § 27.1045.

(b)

Maximum ambient atmospheric tem-

perature. A maximum ambient atmos-
pheric temperature corresponding to

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§ 27.1091

sea level conditions of at least 100 de-
grees F. must be established. The as-
sumed temperature lapse rate is 3.6 de-
grees F. per thousand feet of altitude
above sea level until a temperature of

69.7 degrees F. is reached, above

which altitude the temperature is con-
sidered constant at

69.7 degrees F.

However, for winterization installa-
tions, the applicant may select a max-
imum ambient atmospheric tempera-
ture corresponding to sea level condi-
tions of less than 100 degrees F.

(c)

Correction factor (except cylinder

barrels). Unless a more rational correc-
tion applies, temperatures of engine
fluids and power-plant components (ex-
cept cylinder barrels) for which tem-
perature limits are established, must
be corrected by adding to them the dif-
ference between the maximum ambient
atmospheric temperature and the tem-
perature of the ambient air at the time
of the first occurrence of the maximum
component or fluid temperature re-
corded during the cooling test.

(d)

Correction factor for cylinder barrel

temperatures. Cylinder barrel tempera-
tures must be corrected by adding to
them 0.7 times the difference between
the maximum ambient atmospheric
temperature and the temperature of
the ambient air at the time of the first
occurrence of the maximum cylinder
barrel temperature recorded during the
cooling test.

(Secs. 313(a), 601, 603, 604, and 605 of the Fed-
eral Aviation Act of 1958 (49 U.S.C. 1354(a),
1421, 1423, 1424, and 1425); and sec. 6(c) of the
Dept. of Transportation Act (49 U.S.C.
1655(c)))

[Doc. No. 5074, 29 FR 15695, Nov. 24, 1964, as
amended by Amdt. 27–11, 41 FR 55470, Dec. 20,
1976; Amdt. 27–14, 43 FR 2325, Jan. 16, 1978]

§ 27.1045

Cooling test procedures.

(a)

General. For each stage of flight,

the cooling tests must be conducted
with the rotorcraft—

(1) In the configuration most critical

for cooling; and

(2) Under the conditions most critical

for cooling.

(b)

Temperature stabilization. For the

purpose of the cooling tests, a tempera-
ture is ‘‘stabilized’’ when its rate of
change is less than two degrees F. per
minute. The following component and

engine fluid temperature stabilization
rules apply:

(1) For each rotorcraft, and for each

stage of flight—

(i) The temperatures must be sta-

bilized under the conditions from
which entry is made into the stage of
flight being investigated; or

(ii) If the entry condition normally

does not allow temperatures to sta-
bilize, operation through the full entry
condition must be conducted before
entry into the stage of flight being in-
vestigated in order to allow the tem-
peratures to attain their natural levels
at the time of entry.

(2) For each helicopter during the

takeoff stage of flight, the climb at
takeoff power must be preceded by a
period of hover during which the tem-
peratures are stabilized.

(c)

Duration of test. For each stage of

flight the tests must be continued
until—

(1) The temperatures stabilize or 5

minutes after the occurrence of the
highest temperature recorded, as ap-
propriate to the test condition;

(2) That stage of flight is completed;

(3) An operating limitation is

reached.

[Doc. No. 5074, 29 FR 15695, Nov. 24, 1964, as
amended by Amdt. 27–23, 53 FR 34214, Sept. 2,
1988]

NDUCTION

YSTEM

§ 27.1091

Air induction.

(a) The air induction system for each

engine must supply the air required by
that engine under the operating condi-
tions and maneuvers for which certifi-
cation is requested.

(b) Each cold air induction system

opening must be outside the cowling if
backfire flames can emerge.

induction system, that system must
have drains that discharge fuel—

(1) Clear of the rotorcraft; and
(2) Out of the path of exhaust flames.
(d) For turbine engine powered rotor-

craft—

(1) There must be means to prevent

hazardous quantities of fuel leakage or
overflow from drains, vents, or other
components of flammable fluid systems