Under current FAA/NTSB rules, nothing, the forecast stands
until officially amended.

The old joke, summer time forecast...
Chance of severe thunderstorms and tornadoes along and 1,000
miles either side of a line from 150 miles south of
Washington, DC to 300 miles north of San Francisco, CA. Tops
to FL600.

Winter forecast, same line from an unknown location to an
unknown location, with this...
Blizzard and whiteout conditions over the continent and
coastal waters, chance of moderate to severe icing from the
surface to FL240.

The forecast calls "wolf" so many times that pilots and
ground pounders became complacent. At least here in Kansas,
the new standard for issuing a "severe thunderstorm warning"
was changed for the 2005 season. They increased the size of
the hailstones and the winds that trigger a warning so there
would be fewer warnings.

Since Kansas can have steady winds of 25 to 40 knots and
higher gusts, without being associated with any storm, the
severe T storm warning of gusts to 60 mph didn't really
alert most locals.


--
James H. Macklin
ATP,CFI,A&P

"pgbnh" wrote in message
. ..
| What if anything happens to the whole "known versus
forecast" issue if there
| is a pirep for "negative icing in clouds".
| "Matt Whiting" wrote in message
| ...
| John Doe wrote:
| Ok, I know this is one of those "it depends" answers,
but I'm curious as
| to what folks are willing to do in the winter time.
|
| Assumptions:
|
| Single engine piston aircraft with NO de-icing
equipment.
|
| Situation:
|
| It's wintertime. You want to fly XC and there are
midlevel clouds in the
| forecast with the potential for icing to occur.
|
| It looks like the band is thin enough to climb through
and cruise in the
| clear above the weather.
|
| SO:
|
| 1) If the cloud layer is forecast to potentially have
icing, can you
| legally and would you climb through the layer to get up
high for your
| trip? how thick a layer, type of forecast, time spent
in the layer, etc.
| What would you be willing to risk transition through
possible icing?
|
| I believe the recent interpretations is that this would
be illegal as the
| cloud layer at below freezing temps would constitute an
area of "known"
| icing and thus penetrating it would not be legal. As to
what I would do
| personally ... well, I won't answer that here! :-)
|
|
| 2) Would that change any if those same conditions were
now reported icing
| from a recent PIREP?
|
| It would change my personal view of the situation, but I
don't think it
| changes the legality.
|
|
| 3) If it's reported, can you transit the cloud layer
legally?
|
| I don't believe you can do so legally.
|
|
| 4) Let's say yoru trip starts off VFR but by the time
you get to your
| destination, a cloud layer has formed that has reported
icing in it. Can
| or or would you be willing to transit this layer to
land at this
| destionation or would you turn around or divert to land
someplace to stay
| out of the clouds?
|
| Again it depends, but if I had sufficient fuel, I'd
probably divert. If I
| was low on fuel, I'd descend through the layer.
|
| Matt
|
|