AOPA Turbine Pilot Magazine - September 2024 - 20

PROFICIENT PILOT
Rudder shy?
It's OK to use your feet
BY BARRY SCHIFF / AOPA Foundation Legacy Society chairman
IT HAS BE EN said that rudders would be little more than
useless appendages if ailerons were perfectly designed. This
is an obvious overstatement. Even if adverse yaw effect were
eliminated, a rudder would still be needed for slipping, stall/spin
recovery, crosswind landings, and climbing.
Designers have been effective, however, in eliminating so
much adverse yaw effect from modern lightplanes that the need
for a rudder during normal maneuvering is minimal. Pilots can
roll into and out of turns with their feet flat on the floor and barely
notice the consequences. As a result, many pilots have become
rudder shy. This is especially true of military pilots who learn to
fly in jets and never learned to cope with the idiosyncrasies of
flying airplanes with propellers attached. The flight controls of
jet aircraft are so exquisitely designed that rudder is not needed
during turning normal flight. This helps to explain why so many
pilots tend to counter rolling and yawing moments during stall
recovery using only ailerons, which can lead to loss of control.
A hefty foot and the willingness to use it are especially important
when an engine fails on a conventional multiengine airplane.
On June 28, 1998, however, 307 passengers and crew almost paid
the ultimate price because rudder was not applied as needed.
United Airlines Flight 863, a heavily loaded Boeing 747-400,
departed San Francisco's Runway 28R for Sydney, Australia.
Shortly after the Boeing lifted off and entered a low overcast, the
right inboard engine failed. This was the result of such a severe
compressor stall that the resultant airframe shaking made it
difficult for the pilots to read their instruments. In the meantime,
fog-shrouded San Bruno Mountain, which rises to 1,576 feet msl,
loomed only a few miles ahead. Even when loaded with 200 tons
of fuel, the 747 had enough muscle to climb over that obstacle
using only three engines, but only if properly flown.
The mammoth jetliner yawed right in response to the engine
failure, but instead of applying left rudder to counter that insistent
yaw, the first officer, who was flying the airplane, incorrectly
applied only left aileron. Banking was insufficient to arrest the
yaw, and the Boeing jetliner entered a skidding right turn that led
the airplane directly toward the mountain.
A skidding turn erodes climb performance. In addition,
the deflected ailerons and raised spoilers on the left wing
added substantial drag. (Spoilers deploy automatically on the
20
AOPA PILOT / September 2024
left wing of the 747 when the control wheel is turned left; this
reduces wing lift to help lower the wing and adds drag to counter
adverse yaw effect.)
The rest was predictable. The control wheels began to shake in
response to a computer sensing that the aircraft was approaching
a stall. The proper response to this would be to lower the nose and
reduce angle of attack. But then the ground-proximity warning
system began its loud admonishment: " Terrain! Terrain! Pull Up! "
In response to the urging of other pilots in the cockpit, the first
officer pulled up the nose to convert what little excess airspeed
remained into altitude, which turned out to have been the right
thing to do. The 747 barely cleared the mountain but was so low
that it disappeared from ATC radar, igniting controller fears that
the aircraft had crashed.
For whatever reason, this pilot was reluctant to use rudder
to the extent dictated by the circumstances. Some believe that
this typifies a general decline in basic stick-and-rudder skills.
A commonly observed symptom of this is when a pilot lowers
the right wing-instead of applying right rudder-during climb to
compensate for a single-engine airplane's left-turning tendency.
It seems that those who receive their aerial baptism in tubeand-fabric
taildraggers are typically more skillful at using their
feet. Such aircraft demand an almost incessant use of rudder.
Adverse yaw effect is so relatively strong in these aircraft that one
can almost turn right by moving the stick left.
One cure for being rudder shy is to take instruction in one of
these challenging little taildraggers. Perhaps the same could be
accomplished by learning to fly a glider, which has more adverse
yaw effect than any other genre of fixed-wing aircraft. This is
because the wings are so long, and the ailerons are so far from the
fuselage centerline.
Rudder usage also can be misunderstood. Consider this
definition of crabbing as published in an otherwise respected
aviation dictionary: " Heading the nose of the airplane into a
crosswind by use of rudder to prevent the wind from drifting the
airplane off its course. " And there
are some pilots who actually slip
their airplanes to prevent en
route drifting. I kid you not.
www.BarrySchiff.com
BARRY SCHIFF has flown
363 different types of
aircraft during his 28,000
hours of logged flight time.
http://www.BarrySchiff.com
AOPA Turbine Pilot Magazine - September 2024

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