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Where runway friction is low or nil, aerodynamic braking becomes much more
important. Use aerodynamic drag to your advantage on landing-especially when the
runway is wet or icy. Simpty hold the nosewheel off until it settles on its own.

But braking isn't the only problem.

Skidding is another real hazard on a wet or icy runway.
Improper braking is the villain because locked brakes stop the wheels from rolling, and
braking effectiveness (not to mention steering effectiveness) drops to nothing.

Skidding sideways is a fast ticket to blown tires or collapsed landing gear.

If you have to confront icy or wet conditions, have as many factors going for you as
possible.
Pick a nice, long runway oriented into the wind. If unavailable, consider diverting
elsewhere.

Taxiing on ice is its own headache. If you must taxi, taxi very slowly.

In a twin, use differential power. Also, use reversible props, if so equipped.
Another point: a clean, plowed runway with snow banks alongside at the beginning of a
sunny day may become a sheet of ice when the melting snow freezes at the end of the
day. This is something you might not expect in such pleasant, bright weather.


Snow presents other hazards, too.
It is difficult, if not impossible, to judge snow depth on final. Accident reports bear
this out in spades. Snow of any depth obscures runway markings.

Continued plowing raises snow banks on either side of the runway - a definite hazard. The
more plowing, the closer they get.

Blowing snow can cause depth perception problems. Sometimes, a "white out" results,
like landing inside a light bulb. You can miss the runway entirely.
Landing on an icy or snow-covered runway requires advance planning. Check destination
runway conditions, such as field condition reports, NOTAMS, and/or call to check with
local observers. Never expect conditions to remain constant; they do change rapidly
in winter. Get updated weather en route and always have an alternate ready. Finally,
check UNICOM for an update before landing.
A word of caution, however, on pilot braking reports: use discretion in interpreting reports
of "good" or "poor" braking. These subjective classifications depend on
aircraft type and pilot experience, as well as wind and weather conditions at the time of
the report. In some instances, pilots or FBOs are unwilling to give runway braking reports.
Again, when flying in winter, caution is the watchword. Always leave yourself an out,
and be sure to carry adequate fuel reserves.
Water on the Runway and Dynamic Hydroplaning
Spring, summer, winter or fall - anytime is the time for water on the runway.
When the runway is wet, you may be confronted with dynamic hydroplaning. Dynamic
hydroplaning is a condition in which the airplane rides on a sheet of water rather than on
the runway's surface. Because hydroplaning wheels are not touching the runway, braking
and directional control are almost nil.

You are literally "surfing."

Three Types of Hydroplaning
There are actually three types of hydroplaning:
- Dynamic - where the airplane rides on
standing water;
- Viscous - where a film of moisture covers the painted or
rubber-coated portion of the runway; and,
- Reverted, or melted rubber - where locked tires on
a wet
runway can cause heat so intense that the aircraft is actually riding on a mixture of
steam and melted rubber.
For now, we'll concentrate only on dynamic hydroplaning.
To help minimize dynamic hydoplaning, some runways are grooved to help drain off
water. However, most runways are not.
Tire pressure is a factor in dynamic hydroplaning. By this simple formula you can
calculate the minimum speed, in knots, at which hydroplaning will begin.
In plain language, the minimum hydroplaning speed is determined by multiplying the square
root of the main gear tire pressure, in PSI, by nine.

For example, if your main gear tire pressure is at 36 pounds per square inch, you would
begin hydroplaning at 54 knots.

Landing at higher than recommended touchdown speeds will expose you to a greater
potential for hydroplaning. And once hydroplaning starts, it can continue well below the
minimum, initial hydroplaning speed.
When the runuray is wet, be prepared for hydroplaning and opt for a suitable runway
most aligned with the wind. Landing into the wind gives you the best chance for
directional control, but don't count on it. If you hydroplane, make no abrupt control
movements. Your brakes will be completely useless, so don't use them. Use aerodynamic
braking to your fullest advantage.
In summary, think about runway braking problems well before you land.
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