Pt.33, App. D

14 CFR Ch. I (1-1-19 Edition)

Within the envelope, total water content
(TWC) in g/m3 has been determined based
upon the adiabatic lapse defined by the convective rise of 90% relative humidity air
from sea level to higher altitudes and scaled
by a factor of 0.65 to a standard cloud length

of 17.4 nautical miles. Figure D2 of this Appendix displays TWC for this distance over a
range of ambient temperature within the
boundaries of the ice crystal envelope specified in Figure D1 of this Appendix.

Ice crystal size median mass dimension
(MMD) range is 50-200 microns (equivalent
spherical size) based upon measurements
near convective storm cores.
The TWC can be treated as completely glaciated (ice crystal) except as noted in the
Table 1 of this Appendix.

TABLE 1 - SUPERCOOLED LIQUID PORTION OF
TWC - Continued

Temperature range - 
deg C

Horizontal cloud
length - nautical miles

0 to Section20 ......................

-50 ..............................

LWC - 
g/m3
-1.0

Horizontal cloud
length - nautical miles

0 to Section20 ......................
< Section20 ..........................

Indefinite ......................
......................................

LWC - 
g/m3
-0.5
0

The TWC levels displayed in Figure D2 of
this Appendix represent TWC values for a
standard exposure distance (horizontal cloud
length) of 17.4 nautical miles that must be
adjusted with length of icing exposure.

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TABLE 1 - SUPERCOOLED LIQUID PORTION OF
TWC

Temperature range - 
deg C