Power Lines..

[Dan[_1_]]

I've seen power lines marked on sectionals. How high are the highest
major power transmission lines? They look quite high from the ground,
but there's not much to give perspective.

--Dan

[Grumman-581[_1_]]

On 20 Aug 2006 22:18:35 -0700, "Dan" > wrote:
> I've seen power lines marked on sectionals. How high are the highest
> major power transmission lines? They look quite high from the ground,
> but there's not much to give perspective.

They vary depending upon a lot of factors from what I understand...
The highest one is over in Europe and is 227 meters tall...

http://en.wikipedia.org/wiki/Elbe_crossing_2

Most of the ones that I see locally are probably only 200-300 ft tall
at most...

[Ron Natalie]

Dan wrote:
> I've seen power lines marked on sectionals. How high are the highest
> major power transmission lines? They look quite high from the ground,
> but there's not much to give perspective.
>
> --Dan
>
Power lines are marked for use as visual landmarks, NOT as obstructions.

[Dave S]

Ron Natalie wrote:
> Dan wrote:
>
>> I've seen power lines marked on sectionals. How high are the highest
>> major power transmission lines? They look quite high from the ground,
>> but there's not much to give perspective.
>>
>> --Dan
>>
> Power lines are marked for use as visual landmarks, NOT as obstructions.

Agreed.. the right of ways are very distinctive when they head off
through forestland..

I live on the gulf coast, and pretty much the vast majority are 200 feet
or less. Crossing a major ship channel, or the mississippi, you may find
them up to 500 feet agl though, to allow ships to pass under.

Dave

[john smith]

In article >,
Ron Natalie > wrote:

> Power lines are marked for use as visual landmarks, NOT as obstructions.

Unless it is a catanary spanning a valley.

[Doug[_1_]]

There are some awesome powerlines spanning valleys in Idaho near the
Snake River and let me tell you they are a loong way up from the bottom
of the valley, easily 500', probably 1000' or more.... Some of the
lines are on the sectional. I've never seen a power line on a sectonal
marked with obstruction footage, but they might exist.

john smith wrote:
> In article >,
> Ron Natalie > wrote:
>
> > Power lines are marked for use as visual landmarks, NOT as obstructions.
>
> Unless it is a catanary spanning a valley.

[Ron Natalie]

Doug wrote:
> There are some awesome powerlines spanning valleys in Idaho near the
> Snake River and let me tell you they are a loong way up from the bottom
> of the valley, easily 500', probably 1000' or more.... Some of the
> lines are on the sectional. I've never seen a power line on a sectonal
> marked with obstruction footage, but they might exist.
>
> john smith wrote:
>> In article >,
>> Ron Natalie > wrote:
>>
>>> Power lines are marked for use as visual landmarks, NOT as obstructions.
>> Unless it is a catanary spanning a valley.
>

I was assuming we were talking the normal chart power line symbol
(these look like little power line towers with lines connecting
them). Where the towers themselves are obstructions one of the
obstruction symbols (inverted V with a . in it) will be shown.
An example around here is on the Potomac river just north
of Quantico, VA (more apparent on the Washington/Baltimore
TAC chart than the Washington Sectional).

[john smith]

In article . com>,
"Doug" > wrote:

> I've never seen a power line on a sectonal
> marked with obstruction footage, but they might exist.

Several years ago, the FAA added the symbol for a catenary by
highlighting/darkening/thickening the line where it is strung across a
valley.

[Grumman-581[_1_]]

On Mon, 21 Aug 2006 15:39:14 GMT, Dave S >
wrote:
> I live on the gulf coast, and pretty much the vast majority are 200 feet
> or less. Crossing a major ship channel, or the mississippi, you may find
> them up to 500 feet agl though, to allow ships to pass under.

They don't need 500 ft to allow the ships to pass underneath, but
since the lines dip in the center between the towers and this is a
function of the distance between the towers, crossing a major waterway
would require the towers to be higher since the distance between
towers is greater... I'm not sure what the tallest ship might happen
to be... Probably 300 ft at the most... According to the following
link, there was a sail powered ship that had a 295 ft carbon fiber
mast... That sounds impressive...

http://www.guinnessworldrecords.com/content_pages/record.asp?recordid=43706

An aircraft carrier requires about 215 ft above the waterline for
clearance of bridges and such... For power lines, you would probably
want to add another 100 or 200 ft for safety...

[Dan[_1_]]

How high must they be to fall into the FAA's definition of
obstructions?

--Dan


Ron Natalie wrote:
> Doug wrote:
> > There are some awesome powerlines spanning valleys in Idaho near the
> > Snake River and let me tell you they are a loong way up from the bottom
> > of the valley, easily 500', probably 1000' or more.... Some of the
> > lines are on the sectional. I've never seen a power line on a sectonal
> > marked with obstruction footage, but they might exist.
> >
> > john smith wrote:
> >> In article >,
> >> Ron Natalie > wrote:
> >>
> >>> Power lines are marked for use as visual landmarks, NOT as obstructions.
> >> Unless it is a catanary spanning a valley.
> >
>
> I was assuming we were talking the normal chart power line symbol
> (these look like little power line towers with lines connecting
> them). Where the towers themselves are obstructions one of the
> obstruction symbols (inverted V with a . in it) will be shown.
> An example around here is on the Potomac river just north
> of Quantico, VA (more apparent on the Washington/Baltimore
> TAC chart than the Washington Sectional).

[Emily[_1_]]

Ron Natalie wrote:
> Dan wrote:
>> I've seen power lines marked on sectionals. How high are the highest
>> major power transmission lines? They look quite high from the ground,
>> but there's not much to give perspective.
>>
>> --Dan
>>
> Power lines are marked for use as visual landmarks, NOT as obstructions.

No kidding. You shouldn't even be worried about power lines, unless
you're spraying or doing some strange kind of helicopter work.

[Capt. Geoffrey Thorpe]

"Dave S" > wrote in message
nk.net...
>...> I live on the gulf coast, and pretty much the vast majority are 200
>feet or less. Crossing a major ship channel, or the mississippi, you may
>find them up to 500 feet agl though, to allow ships to pass under.
>
> Dave

Clearances above water:
Golden Gate Bridge, 220 feet

Brooklyn Bridge 135 feet at mid-span

George Washington Bridge 64.62 meters (212 ft) at mid-span

San Francisco-Oakland Bay Bridge 220 feet (67 m) (west span) 191 feet (58 m)
(east span)

Mackinac Bridge 155 ft (47 m)

What later became known as the Crescent City Connection was the second
bridge to span the Mississippi south of Baton Rouge after the Huey P. Long
Bridge a few miles up river from the city, and the first bridge across the
river in New Orleans itself. 51.8 meters (170 feet)

Ambassador Bridge and Blue Water Bridge (both run between Michigan and
Ontario over the Detroit and St. Claire Rivers respectively) are both 152
feet above the water.

source: en.wikipedia.org

--
Geoff
The Sea Hawk at Wow Way d0t Com
remove spaces and make the obvious substitutions to reply by mail
When immigration is outlawed, only outlaws will immigrate.

[Dave S]

Capt. Geoffrey Thorpe wrote:

>
> Clearances above water:
> Golden Gate Bridge, 220 feet
>
> Brooklyn Bridge 135 feet at mid-span
>
> George Washington Bridge 64.62 meters (212 ft) at mid-span
>
> San Francisco-Oakland Bay Bridge 220 feet (67 m) (west span) 191 feet (58 m)
> (east span)
>
> Mackinac Bridge 155 ft (47 m)
>

Fred Hartmann bridge in Baytown (Houston) over the ship channel 178 feet
with 440 ft suspension towers. Tall power lines nearby that cross the
channel.

Cooper River Bridge in Charleston, SC (near a former naval base) 200 ft
clearance with over 575 ft suspension towers.

[Stefan]

Emily schrieb:

> No kidding. You shouldn't even be worried about power lines, unless
> you're spraying or doing some strange kind of helicopter work.

Or unless you're flying in the mountains, where they become too often
deadly traps to flatlanders who don't even worry about them.

Stefan

[Jim Macklin]

Or where powerlines cross a river valley, airplanes
following the valley can often be well clear of the river
and still be caught by the powerlines strung from towers on
the ridges on each side.



"Stefan" > wrote in message
. ..
| Emily schrieb:
|
| > No kidding. You shouldn't even be worried about power
lines, unless
| > you're spraying or doing some strange kind of helicopter
work.
|
| Or unless you're flying in the mountains, where they
become too often
| deadly traps to flatlanders who don't even worry about
them.
|
| Stefan

[Gene Seibel]

Ocassionally I see one with obstruction lighting. I'm guessing those
are over 200 feet and the rest under 200.
--
Gene Seibel
Gene & Sue's Aeroplanes - http://pad39a.com/gene/planes.html
Because we fly, we envy no one.


Dan wrote:
> I've seen power lines marked on sectionals. How high are the highest
> major power transmission lines? They look quite high from the ground,
> but there's not much to give perspective.
>
> --Dan

[Leonard Milcin Jr.]

Jim Macklin wrote:
> Or where powerlines cross a river valley, airplanes
> following the valley can often be well clear of the river
> and still be caught by the powerlines strung from towers on
> the ridges on each side.

Or even worse, kill other people.

http://en.wikipedia.org/wiki/Cavalese_cable-car_disaster

"The restrictions in effect at the time required a minimum flying height
of 2000 feet (600 m); the pilot said he thought they were 1000 feet (300
m). The cable was cut at a height of 360 feet (110 m)."



Leonard