Ice... Not Our Idea Of A Good Time
For those of us who have "hit the boots" (or the equivalent
system on your favorite bird) a few times in the last few days due
to the ever-present seasonal 'charms' of in-flight icing, we
thought a series of short tips from Cirrus Design's Scott Winter
(yes, that IS his real name) might help us all to consider some of
the realities of this time of year. So... here is the last of seven
tips for dealing with icing. Y'all be careful out there!
Icing Aero-Tip 7: Braking Action Reports
When snow and ice cover a runway, braking action
will likely be reduced. To inform pilots as to the current
conditions of the runways, braking action reports will likely be
made available. Braking action reports are reported as good, fair,
poor or nil. Good means that there is no degradation of braking
action. Fair means that there may be some degradation to braking
action.
Poor means braking action is very degraded, and nil
means there is no braking action. If a braking action report is
between two conditions, i.e., fair to poor, pilots are encouraged
to assume the worse of the two conditions or poor. Aside from
verbal reports, airports may use MU (pronounced mew) values to
determine braking effectiveness. At larger airports, a truck may
drive on the runway with a device that measures surface friction to
obtain MU values.
Anytime MU values are being reported, it is likely
that there is some degradation to braking. MU values greater than
40 are considered "good," 40-30 are considered "fair," 30-20 are
considered "poor," and values less than 20 are considered "nil." MU
values are normally reported at three locations on a runway:
touchdown, midfield, and rollout. Aside from MU values, inquire
about runway conditions such as standing snow, melting ice,
etc.
About Scott Winter
At the time that this series was authored, Scott was a member of
the Flight Standards Department at Cirrus Design Corporation in
Duluth, MN (one of those places that see more than its fair share
of icing encounters). Born and raised in Milwaukee, WI, he
discovered his passion for aviation at an early age. After
obtaining his Private Pilot Certificate prior to his senior year in
high school, he attended Minnesota State University, Mankato (MSU)
and graduated with a Bachelor's degree majoring in Professional
Flight. In December 2006, he completed his Master's of Science
degree from MSU spending time focusing on aviation weather,
scenario-based training, and visualization techniques to enhance
the methods used to educate aviators.
Note: ANN thanks Cirrus Pilot William Dobson
and other members of the Cirrus community, for the use of the
excellent SR20 icing pix...
NTSB Final Report: Douglas A-4K
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