Flight Training - August 2019 - 37

TECHNIQUE

The first thing to remember is that you will stop faster
on grass and it will take longer distances to take off. Second, you want to keep any pressure off the nosewheel in
tricycle-gear aircraft. From there, it becomes a matter of
paying attention to any manufacturer recommendations
and performance calculations for a soft-field takeoff
procedure. With that in mind, each grass runway and
condition will offer different performance experiences.
Not all aircraft have published soft-field operations
guidelines. In fact, some aircraft aren't suited to the
activity at all. But many are just fine. If you are flying
a Cessna 172, Piper Warrior, or many other common
general aviation aircraft-even a Cirrus SR22-you may
well find that proper technique will enable you to fly to
airports you didn't know you could visit.
Every summer many pilots work to rebuild proficiency for their grassy runway operations after long
winter gaps where they were stuck to just the plowed,
pavement runways. This is a good way to refresh those
skills, and if you aren't comfortable doing it on your
own, don't be afraid to take someone with you who is.
Hiring an instructor familiar with grass runways or
dragging along another pilot can help you develop or
brush up your soft-field operations skill set.
LOCAL KNOWLEDGE

I can't stress this enough: Take advantage of local
knowledge.
Grassy runways come in a wide variety. Some are
little more than rolled fields; some cross paved
runways; some have known wet spots; some
have industrious gophers that leave holes
periodically. Some are well kept by the
local airport management or airport
tenants, while others go months
between grass cuttings. A few are
not even published on charts, and
can be great options for days when there
are strong crosswinds on the primary runway-
but these runways are only of assistance if you know
about them before arrival.
If you are thinking about using a grass runway,
especially one with which you are not familiar, get more
information. Notices to airmen (notams) are a good
starting point, if there are any. Frequently there won't
be any notams specifically relating to the grass runways
you want to use. When this is the case, make a call.
Calling a local FBO or airport manager can ferret
out good information about the current condition of
sod runways. Someone who is familiar with the area
can share valuable knowledge that you would otherwise have not been able to ascertain.
CONDITIONS

Even if it hasn't been raining at your home airport, that
doesn't mean the grass runway where you plan to land 100
miles away will be dry and firm. And the fact that it hasn't
rained in the last day doesn't mean it will be dry, either.

JARGON

Ground effect

Ground effect is the boost in performance you
get when an airplane is low to the ground: The
surface interferes with the airflow around the wing,
reducing induced drag from wingtip vortices and
creating what feels like a cushion of air under the
aircraft. This aerodynamic phenomenon can punish
bad piloting technique by leading to excessive
floating on landing or letting an airplane lift off at
a slow airspeed but not climb at the same attitude.
But soft-field technique puts it to use for good.
On takeoff, pilots can lift off quickly from a draggy
surface and accelerate in ground effect before
climbing. On landing, staying in ground effect as
long as possible enables touchdown at the
minimum speed.

Some grass runways drain less efficiently than others
and may take weeks to fully firm up. This can be especially problematic in the spring, when rain in some areas
leaves grass runways looking great from the air-but mud
may bog down a landing aircraft or foil a takeoff effort.
Check if it's rained in the area and if there are wet
spots on the runway you intend to use. I use a few runways that are good on one end but not the other for much
of the year. That may be fine if you have a 5,000-foot grass
runway and only need 2,000 feet of it-if you know where
the wet spots are-but could be disastrous if you choose
the wrong end and don't know what to avoid.
In addition to wet or muddy runways, you also
should avoid runways that have big holes (think
gophers), and runways with long grass. All of these conditions will significantly reduce takeoff performance,
can allow gear to sink in, or may cause a rather abrupt
stop on a landing.
WHEN IN DOUBT

If you can't get reliable conditions reports, check it
out yourself. Landing on another, potentially paved,
runway at the airport and checking the grass by
walking it can be a good option to get a better feel for
the conditions. You could also drive it, with permission from or coordination with the airport operator.
Driving a runway in a motor vehicle may help you
find potholes or let you know if the weight of a car
will leave tracks. If a car, truck, or SUV can travel
the runway smoothly without any wet spots or holes,
most light GA aircraft will be able to do the same.
If you don't have the opportunity to check it out
from the ground or are considering landing on a grass
runway you didn't get information about ahead of
time, at least fly over it and give it a good look. Once,
AOPA.ORG/FT 37

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Flight Training - August 2019

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