Typical Guy Wires

Let'sgoflying!

Let'sgoflying!

Touchdown! Greaser!
Joined
Feb 23, 2005
Messages
20,769
Location
west Texas
Display Name
Display name:
Dave Taylor
500’ tower

How far from the base would one expect guy wire anchors, at the greatest?

How far laterally from the tower would guy wires be found, on a 500’ tower, at 100’agl?
(If one were flying at 100’agl, how close could you get?)
 
You're probably looking at the width being somewhere around 60% (minimum, more rare) to 100% (more typical) of the tower's total height. So a 500 ft tower might have guy wires from 300 ft to 500 ft out from the base. There are different variables that play into this, from the tower design to the local geography, so it'll vary a bit.
 
Let'sgoflying! said:
(If one were flying at 100’agl, how close could you get?)
Click to expand...
Half a mile. I have no wish to get any closer to any tower.

I think guys are typically run between 45 and 60 degrees, but I’d suspect it can vary a lot based on tower type, site constraints, etc.
 
Are you putting up a tower for your ham radio antenna? This is a good question in THAT venue.

I wouldn’t even CONSIDER some sort of altitude dependent calculation as anywhere near a good way to approach this sort of thing for flying (or planning) purposes.

Something like 1000’ tower stay 2000’ feet away at ANY altitude up to no less than twice it’s heigh MIGHT be near ok, the aforementioned 1/2 mile is even better.

And I wouldn’t consider see and avoid (a guy wire) as safe or reliable either. Looking for the tower and avoiding with a CLEAR margin in 3 dimensions is ok.
 
Flying at 100' AGL AND flying close to a 500' tower? Yikes - Nothing good can come from that combination. The first time you'd see the wire would be when it tore your wing off.

I don't think even professional crop dusters would fly anywhere near a tower.
 
Last edited:
Assuming a 45 degree angle (base of cable = tower height away from tower), 500 foot tower, at 100 AGL it would be (500-100) = 400 feet.
 
I would stay laterally at least 1 to 2 times the height of the tower just to be safe.
 
I considered pipeline and power line patrol after I retired. I had talked to two very successful contractors, one in each specialty. Both had experiences with towers that were not seen the previous month. Who notices a property owner who has augured three holes in his field, and filled them with concrete? Both enjoyed the work, and planned to continue for several more years, then go corporate, maybe. The schedule freedom attracted both of them.

Establish a scan that has an out the windscreen, focused look, EVERY 2 minutes. This is minimal.

Locating all the towers on the aviation charts is not a guarantee that you will not meet uncharted towers, just that they will be relatively small, and harder to see.

Hills and ridges are most likely to have uncharted towers

The slimmer the tower, the further out the guy wires.

The softer the ground, the further out the guy wires.

Captain Thorpes adjustment in for a cruise altitude of 100 feet is to dependent on accurate estimate's, to be safe. The height of the tower, visualized horizontal, is the minimum.

My first training flight included a simulated forced landing, location chosen with malice aforethought. The obvious choice was a large, nearly level field. It had a slim radio tower. The instructor asked what those chunks of concrete were doing out in the middle of where I was planning to land. The guy wires were invisible until we passed at a couple of hundred feet, and then only because I was looking for them.

Fly by the taller towers higher than the top, and tell the customer to use a magnifying glass.

Are they requiring you to fly a GPS based grid? Deviate up.

Heading based? Deviate around.

Do not let them dictated too much that impinges safety. Repeat this last line several times
 
Last edited:
geezer said:
I considered pipeline and power line patrol after I retired
Click to expand...

Awesome, Geezer!
The things you mention are part of my training. Except for brief glimpses at laser altimeter & course line, I am looking OUT.
 
Here is what I’m asking about. (500’ tower; bottom)
(Sorry for the redactions, it’s only right for the customer.)

The vertical course lines in white & red are the routes flown.
The goal is 100’agl, honoring limits within the waiver, and safety issues.

This is the most demanding flying I’ve ever done.
Also note the high line in the bottom right (which I was hopping up and over all day today).




IMG_3644.jpeg
 
WDD said:
Flying at 100' AGL AND flying close to a 500' tower? Yikes - Nothing good can come from that combination. The first time you'd see the wire would be when it tore your wing off.

I don't think even professional crop dusters would fly anywhere near a tower.
Click to expand...
Depends on the pilot and the tower.

There are strategies for avoiding wires when required to work close to towers.
 
Well you're in an airplane. You can just fly over the tower and look down and SEE exactly where the anchors are. Seems a lot simpler than trying to fly an airplane and do trigonometry at the same time.
 
Basically figure on 45 degrees wires. So a 500 foot tower has the anchors 500 feet away. At 100 feet, I would stay a minimum of the tower height away laterally to avoid the wires, remembering your wing stick out a ways, and a gust could be ugly.
 
Pinecone said:
Basically figure on 45 degrees wires. So a 500 foot tower has the anchors 500 feet away. At 100 feet, I would stay a minimum of the tower height away laterally to avoid the wires, remembering your wing stick out a ways, and a gust could be ugly.
Click to expand...

Easy way to make a clipped-wing Cessna.
 
What might we ask are you doing ?
 
A friendly reminder to any of you visiting Fullerton. This abomination, on the left base leg to Runway 6 and the crosswind leg for right (normal) pattern for 24, still exists, after getting hit TWICE. I witnessed the second hit, a 182 hitting a guy wire.

kfi.JPG
 

Attachments

  • kfi.jpg
    kfi.jpg
    131.3 KB · Views: 1
Let'sgoflying! said:
Here is what I’m asking about. (500’ tower; bottom)
(Sorry for the redactions, it’s only right for the customer.)

The vertical course lines in white & red are the routes flown.
The goal is 100’agl, honoring limits within the waiver, and safety issues.

This is the most demanding flying I’ve ever done.
Also note the high line in the bottom right (which I was hopping up and over all day today).




View attachment 117828
Click to expand...
Could the grid not be offset to the west just enough to center the tower between two of them?
 
DaleB said:
Could the grid not be offset to the west just enough to center the tower between two of them?
Click to expand...

I like the idea, but the practicality of it…. today I passed by a dozen towers, (only 3 were even marked on the sectional) it would not be possible to move the tracks - it’s simpler & makes more sense to follow the instructions “don’t hit em’”

-if you move the tracks to avoid one, you’d put others right on next track.
-the tracks have been there decades and it would interfere with the project to move them
-etc
 
Silvaire said:
Well you're in an airplane. You can just fly over the tower and look down and SEE exactly where the anchors are. Seems a lot simpler than trying to fly an airplane and do trigonometry at the same time.
Click to expand...

a) no we don’t have time to pre-fly over every tower, not practical.
b) no pythagorus in the cockpit; consider it due diligence to ask about this before commencing flight; ie pre-flighting.
 
So if you’ve got a 500’ tower, and let’s say assuming 500’ horizontal clearance is enough… how accurately can you estimate 500’ lateral distance? That would be my worry. One of them.
 
Let'sgoflying! said:
a) no we don’t have time to pre-fly over every tower, not practical.
b) no pythagorus in the cockpit; consider it due diligence to ask about this before commencing flight; ie pre-flighting.
Click to expand...
You are smart, and I'm sure you've thought about this, but I'll mention it anyhow. Vision is more important in this type of flying than it has ever mattered before. The typical two year cycle of updating prescription/glasses is not enough. A slight degradation in vision that hasn't been corrected will not be noticeable to you in day to day life but could easily kill you when you're flying that low over that much ground.

While instructing, I have been known to check folks (and my) vision by having them call out towers they see & comparing that against what I can see. A little bit of vision degradation results in a tower a good eye might detect many minutes before impact not being noticed until a few seconds before impact. On more than one occasion this resulted in someone updating their vision prescription.

In instrument flying, we test our instruments as much as we can. In this work, the same thing needs to be done with the Mark 1 Eyeball.

One final tip, while flying low it can be tempting to focus your vision close to you (as you are close to hitting things). This is a dangerous trap. If your eyes are only focusing on what will happen in the next few seconds, you will only have a few seconds to react to such obstacles. Make sure your vision is focused as far ahead as you want time to react.
 
Last edited:
Jeff Oslick said:
A friendly reminder to any of you visiting Fullerton. This abomination, on the left base leg to Runway 6 and the crosswind leg for right (normal) pattern for 24, still exists, after getting hit TWICE. I witnessed the second hit, a 182 hitting a guy wire.
Click to expand...

I learned to fly at Fullerton in the mid 1960s, when the top of the original KFI tower was 823' MSL, and the traffic pattern was just 73 feet higher. Imagine all the patterns flown for runway 24 on hot, smoggy afternoons in clapped-out, overloaded Cessna 150s, making their climbing turns from crosswind to downwind in the haze somewhere out there near the tower. In those days there were no strobe lights on the tower, just dim, flashing red incandescent lights.

Screen Shot 2023-06-07 at 8.59.25 PM.jpg

I grew up in La Mirada, just a mile north of the KFI tower. The station was a 50,000-watt, clear-channel blowtorch that, unless your transistor radio had excellent selectivity, overpowered eveything in the lower half of the AM band. With an ADF you could navigate home from Mars. Pick up the telephone receiver at home and you could plainly hear KFI's programming over the dial tone. My mother claimed she could hear it in the fillings of her teeth.
 
Pinecone said:
You think staying at least 1x the height of the tower away will have you hit the wires?
Click to expand...
Pinecone said:
Basically figure on 45 degrees wires. So a 500 foot tower has the anchors 500 feet away. At 100 feet, I would stay a minimum of the tower height away laterally to avoid the wires, remembering your wing stick out a ways, and a gust could be ugly.
Click to expand...
SoonerAviator said:
Easy way to make a clipped-wing Cessna.
Click to expand...
I think you're forgetting about the 45 degree angle part. The wires are anchored at ground level and you will be above if you overfly the anchor point at 100 ft AGL.

Cessna wing span is like 36 ft. If you were dead centered over the guy wire ground anchor point, with the tower on your left, you would have 18 ft of wing exposed towards the "rising guy". If you were at 100 ft AGL, your left wing tip would clear the rising guy by 82 ft.

A380 wing span is 262 ft. Dead centered, 131 ft of wing exposed. At 100 ft AGL, the guy wire would eat the wing 31 ft inboard from the tip. Don't do Dave's job in an A380.
 
Last edited:
Let'sgoflying! said:
...no we don’t have time to pre-fly over every tower, not practical...
Click to expand...

Okay but personally I don't fly below the elevation of ground based obstacles without a reconnoiter, that's just the way I was taught. "Didn't have time to check it out" ain't a very good excuse if you hit something.
 
Let'sgoflying! said:
a) no we don’t have time to pre-fly over every tower, not practical.
Click to expand...

it’s not possible to pause and restart your mission in flight?

I have spent many thousands of hours operating at altitudes below obstacles. You always have time to survey an obstacle before operating low and tight. Always.

Based off your posts I’m not sure just how close your are flying to stuff. Just be careful. There is always time to be safe. Don’t let an urgency of time drive your decisions.
 
Last edited:
SoonerAviator said:
Easy way to make a clipped-wing Cessna.
Click to expand...
jesse said:
I think you're forgetting about the 45 degree angle part. The wires are anchored at ground level and you will be above if you overfly the anchor point at 100 ft AGL.

Cessna wing span is like 36 ft. If you were dead centered over the guy wire ground anchor point, with the tower on your left, you would have 18 ft of wing exposed towards the "rising guy". If you were at 100 ft AGL, your left wing tip would clear the rising guy by 82 ft.

A380 wing span is 262 ft. Dead centered, 131 ft of wing exposed. At 100 ft AGL, the guy wire would eat the wing 31 ft inboard from the tip. Don't do Dave's job in an A380.
Click to expand...

I was referring to the "gust" part of his comment. 82ft of clearance from a Cessna wingtip disappears quickly with a gust/crosswind. My comment was also tongue-in-cheek, so there's that.
 
SoonerAviator said:
I was referring to the "gust" part of his comment. 82ft of clearance from a Cessna wingtip disappears quickly with a gust/crosswind. My comment was also tongue-in-cheek, so there's that.
Click to expand...
The real problem with wires is a lack of depth perception. Have to use the attachment points to establish good perception of distance. The poles in the case of power lines and the tower/ground blocks for towers.

if you try looking at the wires you’ll eventually find them with the aircraft.
 
I did 1600nm in the last 4 days, all at 100'agl.
It was totally off the beaten (aviation) path for me; never have I experienced anything like it.
All my flying (since 1978) has been avoiding the ground and all that it entails, not hugging it, lol!
So I had to fight decades of 'this isn't right' 'No, no, no!'.

The experience reminded me that there are many, many types of aviating that I have never been part of (such as what aerial applicators do on a daily basis for example).
It was great to broaden my aviation experience this way.

To describe it: I was asked to fly a precise lateral path (all by hand) following parallel lines a half mile apart, depicted on a 396, and maintaining 100' agl (the goal is +/-20') - in rolling terrain. The leg lengths ranged maybe from 10-30mi long. At the end of each leg, enrichen/power/bank and try to enter the new path at the correct altitude, heading and groundspeed (forgot to mention the speed also must be 85kts throughout)
Then power setting, lean again, follow the track (looking down at the gps and across at the laser altimeter was done maybe every 5 seconds the entire time - as the only way to provide a quality result)
Managing the engine, fulfilling sudden requests to go back and look at something (low level canyon turns), negotiating unmarked obstacles plus the forests of windmills and towers added to the fun. I had no idea how many rural homes have 80' antennae on their property! I flew around a bunch of very tall drilling rigs. I flew one plot that involved passing up and over the same 150'? high tension line...maybe 30x. I think on the first pass I was at 300' before descending beyond! I tried to guard against complacency (one gets really bored and there is an insidious deterioration in alertness after a few hours of the same thing) but soon those deadly wires were passing only 30' below the wheels and it was not alarming anymore.

After-flight maintenance/servicing duties were minimal....but took some time.
Maybe it's my age, but learning this new task, getting up before 5:00am, for 6-7 hour, very demanding days has Wore Me Out!

Thanks for information/tips/cautions given previously.
 
Oh my gawd…. Are you really considering a job that you need to fly below towers and worry about guy wires???

Oh my….
 
No. Thank. You.
 
Wrong question to ask. The answer is you should have at least 1/2 mile clearance from the tower.
 
You must log in or register to reply here.
Back
Top