Chapter 9 — Ground Reference Maneuvers
Rectangular Course
Normally, the rectangular course is the first ground
reference maneuver the pilot is introduced to. [Figure 9-4]
The rectangular course is a training maneuver in
which the ground track of the powered parachute is
equidistant from all sides of a selected rectangular
area on the ground. The maneuver simulates the conditions
encountered in an airport traffic pattern. While
performing the maneuver, the altitude should be held
constant.
The maneuver assists the student pilot in perfecting:
• Practical application of the turn.
• The division of attention between the flightpath,
ground objects, and the handling of the powered
parachute.
• The timing of the start of a turn so that the turn
will be fully established at a definite point over
the ground.
• The timing of the recovery from a turn so that a
definite ground track will be maintained.
• The establishing of a ground track and the
determination of the appropriate “crab” angle.
Like those of other ground track maneuvers, one of
the objectives is to develop division of attention between
the flightpath and ground references, while
controlling the powered parachute and watching for
other aircraft in the vicinity. Another objective is to
develop recognition of drift toward or away from a
line parallel to the intended ground track. This will be
helpful in recognizing drift toward or from an airport
runway (landing area) during the various legs of the
airport traffic pattern.
For this maneuver, a square or rectangular field, or an
area bounded on four sides by section lines or roads,
should be selected well away from other air traffic.
The powered parachute should be flown parallel to
and at a uniform distance from the field boundaries,
not necessarily directly above the boundaries. For best
results, the flightpath should be positioned outside the
field boundaries just far enough that they may be easily
observed from either pilot seat by looking out the
side of the powered parachute. If an attempt is made
to fly directly above the edges of the field, the pilot
will have no usable reference points to start and complete
the turns. The closer the track of the powered
parachute is to the field boundaries, the steeper the bank necessary at the turning points. Also, the pilot
should be able to see the edges of the selected field
while seated in a normal position and looking out the
side of the powered parachute during either a lefthand
or right-hand course. The distance of the ground
track from the edges of the field should be the same
regardless of whether the course is flown to the left or
right. All turns should be started when the powered
parachute is abeam the corner of the field boundaries
headed downwind where ground reference maneuvers
are typically started. These should be the determining
factors in establishing the distance from the boundaries
for performing the maneuver.
Although the rectangular course may be entered from
any direction, this discussion assumes entry on a
downwind.
On the downwind leg, the wind is a tailwind and results
in an increased groundspeed. Consequently, the
turn onto the next leg is entered with a fairly fast rate
of turn and a higher (medium) bank. As the turn progresses, the bank angle is reduced gradually because
the tailwind component is diminishing, resulting in
a decreasing groundspeed. During and after the turn
onto this leg (the equivalent of the base leg in a traffic
pattern), the wind will tend to drift the powered parachute
away from the field boundary. To compensate
for the drift, the amount of turn will be more than
90°.
The rollout from this turn must be such that as the
wing becomes level, the powered parachute is turned
slightly toward the field and into the wind to correct
for drift. The powered parachute should again be
the same distance from the field boundary and at the
same altitude, as on other legs. The base leg should be
continued until the upwind leg boundary is being approached.
Once more the pilot should anticipate drift
and turning radius. Since drift correction was held on
the base leg, it is necessary to turn less than 90° to
align the powered parachute parallel to the upwind leg
boundary. This turn should be started with a medium
bank angle with a gradual reduction to a shallow bank as the turn progresses. The rollout should be timed
to assure paralleling the boundary of the field as the
canopy becomes level.
While the powered parachute is on the upwind leg, the
next field boundary should be observed as it is being
approached, to plan the turn onto the crosswind leg.
Since the wind is a headwind on this leg, it is reducing
the powered parachute’s groundspeed and during the
turn onto the crosswind leg will try to drift the powered
parachute toward the field. For this reason, the
roll-in to the turn must be slow and the bank relatively
shallow to counteract this effect. As the turn progresses,
the headwind component decreases, allowing
the groundspeed to increase. Consequently, the bank
angle and rate of turn are increased gradually to assure
that upon completion of the turn the crosswind
ground track will continue the same distance from the
edge of the field. Completion of the turn with the wing
level should be accomplished at a point aligned with
the upwind corner of the field.
Simultaneously, as the wing is rolled level, the proper
drift correction is established with the powered parachute
turned into the wind. This requires that the turn
be less than a 90° change in heading. If the turn has
been made properly, the powered parachute should
be the same distance from the field boundary and
at the same altitude, as on other legs. While on the
crosswind leg, the wind correction angle should be
adjusted as necessary to maintain a uniform distance
from the field boundary.
As the next field boundary is being approached, the
pilot should plan the turn onto the downwind leg.
Since a wind correction angle is being held into the
wind and away from the field while on the crosswind
leg, this next turn will require a turn of more than 90°.
Since the crosswind will become a tailwind, causing
the groundspeed to increase during this turn, the
bank initially should be medium and progressively
increased as the turn proceeds. To complete the turn,
the rollout must be timed so that the wing becomes
level at a point aligned with the crosswind corner of
the field just as the longitudinal axis of the powered
parachute again becomes parallel to the field boundary.
The distance from the field boundary should be
the same as from the other sides of the field.
Usually, drift should not be encountered on the upwind
or the downwind leg, but it may be difficult to
find a situation where the wind is blowing exactly
parallel to the field boundaries. This would make it
necessary to use a slight wind correction angle on all
the legs. It is important to anticipate the turns to correct for groundspeed, drift, and turning radius. When
the wind is behind the powered parachute, the turn
must be faster and steeper; when it is ahead of the
powered parachute, the turn must be slower and shallower.
These same techniques apply while flying in
airport traffic patterns.
Common errors in the performance of rectangular
courses are:
• Failure to adequately clear the area.
• Failure to establish proper altitude prior to
entry. (Typically, entering the maneuver while
descending.)
• Failure to establish appropriate wind correction
angle resulting in drift.
• Gaining or losing altitude.
• Abrupt control usage.
• Inability to adequately divide attention between
powered parachute control, maintaining ground
track, and maintaining altitude.
• Improper timing in beginning and recovering
from turns.
• Inadequate visual lookout for other aircraft.
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