Always remain in a position where you can turn
toward lowering terrain.
Never fly beyond the point of no return.
the point of no return
The "point of no return" is defined
as the point on the ground of rising terrain where the terrain out
climbs the aircraft. The turn-around point is determined as the
position where, if the throttle is reduced to idle, the aircraft can
be turned around during a glide without impacting the
terrain.
(It is not proper technique to reduce
the throttle for the turnaround. This merely denotes the point where
the turnaround must be initiated.)
turn around point
More important than the "point of no
return" is the "turn around point." What or where exactly is
this position where, if the throttle is reduced to idle, the aircraft can
be turned around during a glide without impacting the terrain?
The reason it is an elusive value is because
of the variables that may be encountered. If the airplane is flying
upslope terrain at a high speed, the turn around point will be further up
the upslope than it would be if the airplane is flying at minimum
airspeed.
Usually, if a pilot gets into trouble while
flying upslope terrain, he has experienced a phenomena known as "short
arm" effect. The self-preservation instinct causes a pilot to
unconsciously pull back on the control wheel to avoid the rising terrain.
The airplane slows down and this reduction in airspeed is usually
imperceptible to the pilot, who is probably directing his attention
outside the airplane.
As the pilot, flying at or near the minimum
controllable airspeed, realizes he needs to turn around, the density
altitude may preclude a level flight turn around. It becomes necessary to
trade altitude for airspeed during the turn. This is the main reason for
the definition of the "turn around point."
One of the manoeuvres that should be
demonstrated by a good mountain flight school is the "turn around point."
demonstration - turn
around point
NOTE: This demonstration is not required
to safely fly in the mountains. Search pilots operate close to the
terrain (500 feet vertically and 500 feet laterally) on a continuous
basis. It is felt this demonstration, with the required steep
nose-down attitude, will help prevent complacency and cause the search
pilot to continually be aware of his position and
altitude.
While flying upslope terrain in a canyon, the
"student" (actually, the participants are all experienced pilots) is asked
to determine the turn around point. The Cessna 182 or T-41 is used for the
backcountry flying in this course.
The instructor must monitor the position
diligently in order not to fly beyond the turn-around point. This is
definitely a place where complacency will "get you."
|
|
This picture shows flying up
a canyon after
completing the last pass of a contour search |
The contour search
began at the top of the
ridge and moved back and forth with
step-downs in 500-foot intervals |
Most students find this demonstration quite
exuberating ... and most of the time the instructor does too. This
demonstration is made with the power at idle. If the student misjudges the
turn-around point, power is used to get out of the situation, so it is not
as dangerous as it may appear.
Required Altitude
What altitude is required for the Cessna 182
to complete the 80-KIAS turn around? It's going to be about 400-500 feet
above ground level, probably closer to 500 feet.