JPATS Weather - NETC
JPATS Weather - NETC
JPATS Weather - NETC
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<strong>JPATS</strong> AVIATION WEATHER BOOKLET<br />
Icing Intensities and PIREPs<br />
<strong>Weather</strong> personnel cannot generally observe icing; they must rely on PIREPs. When flying<br />
during icing conditions, pilots should report these conditions as indicated in Table 4-3. However,<br />
forecasters attempt to forecast the maximum intensity of icing that may be encountered during a<br />
flight, not necessarily the intensity of icing that will be encountered by a particular aircraft. It<br />
becomes the pilot’s responsibility to make certain that a complete weather briefing is obtained, to<br />
include the information for safe completion of the flight.<br />
Intensity Airframe Ice Accumulation Pilot Report<br />
Trace<br />
Light<br />
Moderate<br />
Severe<br />
Ice becomes perceptible. Rate of accumulation<br />
slightly greater than rate of sublimation. It is<br />
not hazardous even though deicing/anti-icing<br />
equipment is not used, unless encountered for<br />
an extended period of time--over one hour.<br />
The rate of accumulation may create a problem<br />
if flight is prolonged in this environment (over<br />
one hour). Occasional use of deicing/anti-icing<br />
equipment removes/prevents accumulation. It<br />
does not present a problem if the deicing/antiicing<br />
equipment is used.<br />
The rate of accumulation is such that even short<br />
encounters become potentially hazardous and<br />
use of deicing/anti-icing equipment or<br />
diversion is necessary.<br />
The rate of accumulation is such that<br />
deicing/anti-icing equipment fails to reduce or<br />
control the hazard. Immediate diversion is<br />
necessary.<br />
Aircraft identification,<br />
location, time (GMT),<br />
altitude (MSL), type<br />
aircraft, sky cover,<br />
visibility & weather,<br />
temperature, wind,<br />
turbulence, icing, remarks.<br />
Example of PIREP<br />
transmission:<br />
“Pensacola METRO,<br />
Rocket 501, holding 20<br />
miles south of Navy<br />
Pensacola, at 2100Z and<br />
one-six thousand feet,<br />
single T-39 Sabreliner,<br />
we’re IFR in stratus<br />
clouds, temperature –15°<br />
C, winds 330 at 25, no<br />
turbulence, Light Rime<br />
Icing, flying 200 knots<br />
indicated.<br />
Icing may be rime, clear, or mixed:<br />
Rime ice – Rough milky opaque ice formed by the instantaneous freezing of small<br />
super-cooled water droplets.<br />
Clear ice – A glossy, clear or translucent ice formed by the relatively slow freezing of<br />
large super-cooled water droplets.<br />
Mixed ice – A combination of rime and clear ice.<br />
Table 4-3 — Icing Reporting Criteria<br />
4-16 Version 3.2/Dec 08
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