IRFP-01
Metro Review
b. Rime ice
(1) Found predominantly in stratus cloud formations
(2) Most common between -10 degrees C and -20 degrees C
(3) Results from instantaneous freezing of water droplets
(4) Opaque and rough appearance
(5) Continuous icing in these conditions
(6) Tends to erode or blow off quicker than clear ice in non-
icing environment
(7) Dangerous—alters shape of wing surfaces, decreasing lift
and increasing drag
c.
Mixed Icing
(1) Forms in mixed atmospheric conditions that contain both
clear and rime ice
(2) Forms from water droplets of different sizes or when
droplets intermingle with snow or ice particles
(3) Occurs at high altitudes within thunderstorms
(4) Conglomerate appearance, with adverse qualities of both
rime and clear ice
d. Frost
(1) Forms on aircraft at night when temperature and dew point
are within a few degrees of each other and temperature
falls below freezing
(2) Can form during a rapid descent from subfreezing
temperatures
(3) Rough texture greatly inhibits smooth airflow over wing
surface, especially when present on leading edge of wing
(4) Any disruptions of laminar airflow over wing surface create
the effect of a completely new airfoil
(5) Reduces lifting surface of the wing and adds drag
3. Hazards
a. Increases drag and weight
(8-97) Original
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