By Steve Krog, EAA 173799
This story ran in the November 2019 issue of EAA
Sport Aviation.
I’ve previously written
about crosswind operations, but I feel it necessary to expand on these
maneuvers.
Our airport, HXF,
underwent major changes this past summer. Gone is the old 3,000-foot, hard-surface
Runway 11/29, and in its place is the 3,400-foot, hard-surface Runway 09/27.
The new runway required our turf runway, 18/36, to be closed, regraded, and
reseeded.
Consequently, we’ve been
limited to the new hard-surface runway since the airport reopened. Mother
Nature hasn’t cooperated since the opening, and we’ve experienced near direct
90-degree crosswinds in many of the following days. Nearly every training
flight has resulted in both a crosswind takeoff and landing.
The result is that many
of our flight students have become quite proficient in handling crosswind
operations. But crosswinds continue to cause a bit of indigestion among many
pleasure-flying pilots. Consequently, they are not often practiced because of
trepidation. Certainly, these operations do require a bit more pilot skill but
shouldn’t be a deterrent to flying on an otherwise beautiful, sunny day.
To help overcome the
apprehension about crosswind operations, let’s discuss some of the factors that
have an influence either positively or negatively.
Demonstrated Crosswind
Component
How familiar are you with
your aircraft? Do you know the demonstrated crosswind component for the
aircraft that you most often fly? Can you legally fly your aircraft in winds
exceeding the crosswind component?
The demonstrated
crosswind component is just that, demonstrated. It is the highest velocity of
the crosswind encountered for which adequate control of the airplane during
takeoff and landing was demonstrated during certification tests. This number
does not reflect the actual crosswind velocity the aircraft can handle, but
only the greatest velocity experienced during certification testing. The value
published, usually in the pilot’s operating handbook, is not considered to be
limiting.
Yes, you can legally fly
your aircraft in winds exceeding the published crosswind component, but this is
dependent on your capabilities as a pilot. For example, the demonstrated
crosswind component for the Piper J-3 Cub is about 12 knots at 90 degrees.
However, I, as well as many others, have performed takeoffs and landings in
much greater wind velocities.
Several years ago, I was
working with a 500-plus-hour pilot toward getting a tailwheel endorsement. He
was only able to fly one weekend due to his schedule and then was acquiring a
J-3 Cub. Insurance required that he obtain 10 hours of dual instruction.
Saturday was quite breezy but a little more than five hours of instruction were
completed. We were back at it early Sunday morning, but the breeze was
beginning to increase. We began the flight on Runway 18, a turf runway of 2,000
feet. The wind was from 100 degrees at approximately 22 knots with gusts to 28
knots. We focused only on crosswind wheel landings due to the gusty strong
wind.
Progress was being made.
After nearly two hours, we took a short break. While on the ground, we checked
the updated weather and wind conditions only to learn that the wind was
increasing. During the next two hours, we continued our crosswind work until
the peak gust exceeded 30 knots. Anything beyond 30 knots proved to be more
than the Cub could handle using full aileron deflection and full opposite
rudder. Under this wind condition, we could not hold the aircraft straight
after the right main touched down and right brake was applied.
The pilot handled these
conditions quite well and proved to me he was safe to handle stiff crosswinds.
The last hour was used to try different situations pilots might find themselves
in when experiencing crosswinds well beyond their comfort level. In our
situation, we practiced extreme short-field landings, landing across our
200-foot wide turf runway. Done properly, we would easily touch down and roll
to a stop well before using the full width. I’m not advocating that pilots
should go out and do this, but in an emergency situation, pilots need to study
the situation, look at and evaluate all possibilities, and then execute the
best option as calmly as possible if flying to another airport is not an
option.
Determining the
Crosswind Component
Before you sit down to
calculate the crosswind value for your flight today, remember these rules:
- If the
crosswind is obtained by ATC, ATIS, or looking at the windsock, the direction
is magnetic. - If the
crosswind is obtained by looking at a METAR or a TAF, the direction is given
based on true north and will need to be converted to magnetic. - When
calculating the crosswind, always use the full gust component. If ATIS is
telling you the surface winds are 270 degrees at 18 knots, gusting to 25 knots,
use the gust value of 25 knots for your calculation.
You can determine the
crosswind component you’re facing several ways, but there are two methods that
I find easy to understand and use. The first method is using a crosswind chart.
Plot the number of degrees of crosswind off the runway you intend to use. If
you plan to take off on Runway 27 and the wind is reported at 280 degrees and
20 knots, the degree of crosswind is 10 degrees. Next, plot the wind velocity
on the chart. Where the two lines meet is the crosswind value of the wind. In
this example, the crosswind value would be 16 knots.
The second method I find
easy to use and teach is the sixths
rules of thumb. It’s quite simple:
- If angle
= 10 degrees, then crosswind component = 1/6 wind strength - If angle
= 20 degrees, then crosswind component = 2/6 (1/3) wind strength - If angle
= 30 degrees, then crosswind component = 3/6 (1/2) wind strength - If angle
= 40 degrees, then crosswind component = 4/6 (2/3) wind strength - If angle
= 50 degrees, then crosswind component = 5/6 wind strength - If angle
= 60+ degrees, then crosswind component = wind strength
If the crosswind you’re
dealing with is 20 degrees off the runway and the wind is 15 knots, the
crosswind component is 5 knots, or well within most all demonstrated crosswind
component parameters for the types of aircraft we generally fly for pleasure.
Crosswind Control
Dynamics
We’ve all been taught the
proper positioning of the ailerons and elevator when taxiing in wind of any
substance. The longtime rule of thumb is “climb into the wind and dive away
from the wind.”
When ready for takeoff,
the upwind wing aileron is fully deflected upward, causing a downward force on
the wing. This counteracts the lifting force of the crosswind and prevents the
wing from flying or lifting well before the aircraft is ready to fly. For a
tailwheel aircraft, the control stick or yoke should be all the way back, fully
deflecting the elevator upward.
As power is applied and
speed increases, the controls become more effective. Less windward aileron is
needed to prevent the wing from lifting while the downwind aileron is slightly
down creating more lift. Slight but near-constant rudder input is needed for a
smooth, straight takeoff. When dealing with a gusty crosswind, raise the tail
as soon as the elevator becomes effective, positioning the aircraft in a
near-neutral angle of attack. When adequate airspeed is achieved, apply slight
stick back-pressure to create a positive angle of attack. If the wind is quite
gusty, hold the aircraft in the neutral angle of attack attitude until
achieving a speed 5-10 mph above normal liftoff. Just as the aircraft lifts off
the runway, position the aileron and rudder in neutral, allowing the aircraft
to weathervane or establish its own crab angle. Once stabilized, slight but
constant right rudder is applied, which prevents the airplane from drifting off
the centerline as well as offsetting torque and P-factor during the climb-out.
Common Crosswind
Takeoff Mistakes
- Forgetting
to begin the takeoff roll without full aileron deflection, causing the windward
wing to lift well before the aircraft is ready to fly. - Attempting
to force the aircraft into the air before obtaining proper airspeed, causing
the aircraft to side-skid. - Forgetting
to lessen aileron inputs as they become more responsive with increasing speed,
causing the airplane to sharply dip in the direction of the windward wing. - Not
allowing the aircraft to establish a crab angle after lifting off, causing the
aircraft to drift away from the runway and perhaps near other aircraft on the
ground.
Crosswinds are not
inherently dangerous. All pilots should challenge themselves and practice them
from time to time. Practice creates proficiency and proficiency creates both
confidence and safety. Let’s all do a little practice and become better pilots.
Steve Krog, EAA
173799, has been flying for more than four decades and giving tailwheel
instruction for nearly as long. In 2006 he launched Cub Air Flight, a flight training
school using tailwheel aircraft for all primary training. For more from Steve,
read his column, The Classic Instructor, each month in EAA Sport Aviation.