http://www.saflyermag.comthe wires crossing a river or mountain
pass. Once aware of such support towers,
pilots can then search for the wires before
descending to an altitude where the wires
hanging between the towers could pose a
threat.
But, unknown power lines are not
always the threat. Although pilots routinely
fly near power lines and telephone cables
of which they are aware, the problem
can be remembering the wires while
manoeuvring. Wind, turbulence, blinding
sunlight, fatigue, loss of power and
operating on the edge of the aircraft’s
limitations have all contributed to accidents
where pilots have flown into wires that they
knew were there. For pilots who may have
to make a last minute decision to fly over or
under a set of wires, one misjudgement can
result in a potentially fatal wire strike.
The same is true of flying around
towers. Like power lines, towers pose
a potential threat to low flying aircraft.
Considering a tower’s support wires and
the danger zone around a tower extends
both vertically and horizontally around
the tower. The secret is to locate charted
towers while flight planning and planning
how to safely circumnavigates them or over
fly them.
What can we learn from all of this?
Firstly, all pilots should operate high
enough to comply with the Aviation
Regulation's minimum altitude
requirements. Then all pilots should keep
a watchful eye out for towers, power lines
and other such obstacles and remember
where they are for the future, whether
charted, not charted, or not required to
be charted. Pilots should also report new
tower constructions to their local air traffic
facility or flying club and colleagues.
Although our SACAA doesn’t have any
authority over the construction of towers,
in the ideal world they could formally
object to both local and other government
organisations that do have authority over
such construction and local zoning.
Secondly, before flying at a low
altitude, all pilots should carefully review
their appropriate sectional charts for
potential threats along their projected
flight route. This review needs to include
the published chart changes listed in
the Aeronautical Chart Bulletin in the
appropriate Airport/Facility Directory that
have not been added to the published
chart. Pilots should also check for any
NOTAM that might list a new obstacle.
The NOTAM check should also include
any airport, navigational, or operational
changes for the route and airports along
the route at which the pilot may land. The
Airport/Facility Directory also contains
information about hazards around listed
airports.
Finally, a procedure that helicopter
pilots seem to forget from training is the
routine to fly at a safe altitude over the
intended point of landing and once you have
determined that no unknown risks await
you, descend to the respective operating/
landing altitude. Helicopter pilots call this
making a high reconnaissance.
Minimum safe altitudes generally
outline the minimum altitudes that apply
to all aircraft except when necessary for
take-off or landing. The rule states, “Except
when necessary for take-off or landing, no
person may operate an aircraft below the
following altitudes:
(a) Anywhere. An altitude allowing, if
a power unit fails, an emergency
landing without undue hazard to
persons or property on the surface.
(b) Over congested areas. Over any
congested area of a city, town, or
settlement, or over any open air
assembly of persons, an altitude
of 1,000 feet above the highest
obstacle within a horizontal radius of2,000 feet of the aircraft.
(c) Over other than congested areas.
An altitude of 500 feet above the surface,
except over open water or sparsely
populated areas. In those cases, the aircraft
may not be operated closer than 500 feet to
any person, vessel, vehicle, or structure.
(d) Helicopters may be operated at
less than the minimums prescribed in
paragraph (b) or (c) of this section if the
operation is conducted without hazard
to persons or property on the surface. In
addition, each person operating a helicopter
shall comply with any routes or altitudes
specifically prescribed for helicopters by the
Administrator.”
The key to another safe season of flying
is to remember to fly high. There is safety
in altitude. But when you have to operate
low, first fly high while checking for low
altitude dangers, and once you are satisfied
that it is safe to descend, go down to the
appropriate altitude while remembering the
minimum operating rules. Don’t let a power
line or tall tower ruin your day.jLow level flying in river
valleys must be done with
extreme care since this is a
hostile environment where
cables often lurk.