blades or turbine intakes, causing serious damage.
means that the distance a landing point is located from
Shallow water, less than 18 inches deep and with a
a tree is ten times the height of the tree.
firm bottom, can be used as a landing site.
Example: A helicopter landing or taking off near
a 30-foot tree needs at least 300 feet of horizontal
Winds
clearance (fig. 3-2).
When the wind at ground level exceeds 10 knots,
the helicopter must land into the wind.
Ground Obstacles
Obstacles on the ground, such as stumps or rocks,
LANDING SITE DIMENSIONS
should not exceed 1 foot in height on level ground and
Landing site dimensions vary, depending on the
should be less on sloping ground.
number of landing points required. For each landing
point, a fuselage safe circle is cleared of all obstacles,
Gradient (Slopes)
such as stumps, rocks, or bushes. Clear a rotor safe
Ground slope has a considerable effect on
circle of all obstacles that could obstruct the rotor
selecting a landing site or landing point within the LZ.
blades (fig. 3-3).
A helicopter cannot land safely in locations where the
When there is to be more than one landing point
ground slopes more than 14 degrees. When pilots land
within the landing site, separate the landing points so
on a slope, they prefer to land uphill because of the
the helicopters can simultaneously land safely in the
tail down attitude of the helicopter.
landing site. Use figure 3-4 as a guide in selecting the
Surface Conditions
appropriate size landing zone.
Mud, excessive dust, and loose debris are
MARKING THE LANDING ZONE
considered undesirable surface conditions for
helicopters. Mud causes a helicopter to become
Once you have established the LZ, the landing
sites, and the landing points, you need to direct the
bogged down. Excessive dust reduces visibility and
helicopter to the location of the LZ. The proper
compromises the location of the site. Loose debris is
marking of the LZ will aid the pilot in locating it.
dangerous because they are sucked up into the rotor
Figure 3-2.--Horizontal clearance.
Figure 3-3.--Landing point dimensions.
