|
| |
Terrain Flight
|
|
Dennis Dura, Chief Pilot, Ohio Department of Transportation |
| Terrain flying involves flight close to the surface of the
earth. The US Army breaks up terrain flight into nap of the earth (NOE),
contour, and low level. NOE is flying as close to the earth’s surface as
vegetation or obstacles will permit. Airspeed and altitude are varied in
accordance with weather conditions and ambient light. Contour flight is
characterized by varying altitude, adhering to the contours of the earth,
and a constant airspeed. Low level flight is performed at a constant
airspeed and altitude. When performing a reconnaissance, a pilot may go
from one technique to another while maneuvering over a route. Even though
the US Army tailors its training toward helicopters, there is no reason
that an airplane cannot execute terrain flight. As Natural Resource
Pilots, it is not a bad idea to evaluate what mode of flight you are going
to use after a thorough map reconnaissance. This will allow you time to
review what flight techniques may be necessary to safely accomplish the
mission. Because of man made or natural obstacles along a proposed route,
an airplane may select low level flight, whereas a helicopter may choose
contour flight. Weather, rate of closure to obstacles based on airspeed,
flight characteristics and maneuvering space all play a part in the
differences between an airplane flying contour compared to a helicopter.
Since terrain flight requires more attention to detail
and the fatigue factor is high, you must consider human factors such as
physical conditioning, creature comfort in the cockpit, physical well
being, and attitude. Not everyone has the skill level or inclination to
perform terrain flight. A pilot needs to plan in detail and be proficient
in maneuvering close to the ground. For example, a pilot relies heavily on
his peripheral vision to ensure terrain and obstacle clearance. This
requires the pilot to be aware of any blind spots peculiar to the aircraft
being flown because of hazards such as wires. Anytime you find yourself
near roads, man made structures, or below natural terrain features,
suspect wires.
While studying the map, high light all potential
hazards and during the flight be ready for surprises. Detection of
wildlife and vegetation of interest depends upon altitude, airspeed and
weather conditions.
Terrain flight also increases the probability of bird
strikes. A single bird will avoid an aircraft, however the aircraft may
need to be maneuvered to avoid a flock. Distraction and fixation can cause
a pilot to exceed his or the aircraft’s capabilities when trying to
avoid the ground or obstacles. Terrain flight demands a fast cross check
in and out of the cockpit as well as diversification of attention. Some
additional suggestions are avoid flying into the sun, and if visibility is
reduced by the weather, reduce airspeed and/or increase altitude.
Anticipate loss of altitude in turbulence and vertical thermal air
currents. Stay ahead of the aircraft and aviate. Terrain flight can be one
more tool you can use to accomplish your missions as Natural Resource
Pilots.
|
LOW LEVEL
Constant Airspeed
Constant Altitude
CONTOUR
Constant Airspeed
Variable Altitude
NOE
Variable Altitude
Variable Airspeed |
 |
-Dennis Dura, D.P.E. |
|
