(a) General. For the tests prescribed in §29.1041(c), the
following apply:
(1) If the tests are conducted under conditions deviating from the
maximum ambient atmospheric temperature specified in paragraph (b) of this
section, the recorded powerplant temperatures must be corrected under
paragraphs (c) and (d) of this section, unless a more rational correction
method is applicable.
(2) No corrected temperature determined under paragraph (a)(1) of this
section may exceed established limits.
(3) The fuel used during the cooling tests must be of the minimum grade
approved for the engines, and the mixture settings must be those used in
normal operation.
(4) The test procedures must be as prescribed in §§29.1045 through
29.1049.
(5) For the purposes of the cooling tests, a temperature is
"stabilized" when its rate of change is less than 2 °F per minute.
(b) Maximum ambient atmospheric temperature. A maximum ambient
atmospheric temperature corresponding to sea level conditions of at least
100 degrees F. must be established. The assumed temperature lapse rate is
3.6 degrees 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 considered constant at −69.7 degrees F. However, for
winterization installations, the applicant may select a maximum ambient
atmospheric temperature corresponding to sea level conditions of less than
100 degrees F.
(c) Correction factor (except cylinder barrels). Unless a more
rational correction applies, temperatures of engine fluids and powerplant
components (except cylinder barrels) for which temperature limits are
established, must be corrected by adding to them 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 component
or fluid temperature recorded during the cooling test.
(d) Correction factor for cylinder barrel temperatures. Cylinder
barrel temperatures 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 Federal 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)))