If you are going to have a wire strike

[Guest deanfi]

The old cub must of been pretty slow when it hit the wires.

 

Story

 

 https://www.mprnews.org/story/2019/11/24/crews-rescue-pilot-from-plane-caught-in-power-lines-southwest-of-twin-cities?fbclid=IwAR1IFYzdVvD9a9XtsYWi8zxQfm2bGpkQqOMuc0-_Mk7j4EfvAmIh0QgnYOo

 

[johnm]

low more than slow !

 

be good to hear some data on wire strike - the span, weight and strength of power cables are more than a match for most aircraft 

 

 

[Guest deanfi]

low more than slow !

 

be good to hear some data on wire strike - the span, weight and strength of power cables are more than a match for most aircraft 

 

The slow for lack of damage , no wings ripped off , imagine hanging there  waiting to get down , wouldn't  be nice at all

 

 

[KRviator]

low more than slow !

 

be good to hear some data on wire strike - the span, weight and strength of power cables are more than a match for most aircraft 

 

A (very) quick look through Ausgrid's network standards shows the average LV residential cable is 95mm2, so a diameter of around 11mm. The breaking strain for 11mm wire rope is in the vicinity of 16,000lbs, or around 7.2 tonnes. Snagging one isn't going to worry the cable much at all, maybe dislodge it from an insulator or two, but that's it.

 

 

[red750]

Sometimes you just have to sit it out.

 

 

 

[farri]

Like this??? Ron hung like that for over an hour before he could be taken down... Coincidently, he and I were talking about it a couple of days ago! he was frightened the AC might catch fire as there was petrol leaking onto him! once he got his legs out of the pod, he couldn`t take his seat belt off...Never stopped him flying...90 years of age coming up. 

 

So how did he manage to hit the power line? He was going in to land on someone`s private property (not mine) knew the power line was there but simply forgot about it.

 

Franco,

 

 

[Yenn]

I doubt that an 11mm cable with a breaking strain of7.2 tonnes would hold the dead weight, let alone the impact forces of most light lanes.

 

The load in the cable is Length of span multiplied by load, divided by the sag multiplied by 4.

 

 

[Guest deanfi]

few more wire hangars

 

 

[johnm]

I doubt that an 11mm cable with a breaking strain of7.2 tonnes would hold the dead weight, let alone the impact forces of most light lanes.

 

The load in the cable is Length of span multiplied by load, divided by the sag multiplied by 4.

 

 

 

tell us more Yenn - or someone

 

can you do a ruff calculation for us ?

 

 

[cooperplace]

The jab I fly was flown by another pilot into a SWER line. Luckily it missed the prop and snagged the undercarriage. The jab came to a sudden stop on the ground, with not too much damage. One pole was bent, on the other it ripped an insulator off. So I'm told. Still flies fine.

 

 

[poteroo]

There are powerlines, and there are BIG powerlines. It's the spur lines which seem to be most dangerous as they are often hidden behind headlands of bush and trees. A loaded AT-802 with 1350 P&W up front, and doing 110-120 KIAS is going to pull wires off several poles before arriving for the unplanned landing - often safely. But its' built for this. A lightweight aircraft, throttled back for landing, and making 45-50KIAS does not have a lot of energy to dissipate and comes to a rapid halt, often 'hung up'.  The light aircraft doing an illegal beatup is faster, has less time to spot wires, and the impact is harder - more often fatal.

 

I've found that making a 360 over the intended landing area, at 300 ft and configured for flap and with low-medium power, is always a good way to spot wires which may only be 'visible' for about 60* of the orbit due to sunlight/shadow. This before any descending to make the 'strip inspection'.  Most pilots that I review tend to 'inspect' far too low, and far too fast, to actually observe important features and measure the distance.

 

Flying the inspection at 30 ft more often than not requires 101% of the concentration of a non trained low level pilot: you will observe more, and more safely, at above tree top height - perhaps 150 ft agl.  Without fail, the pilot under review never adjusts power to maintain both height agl, and IAS, because they level off for the inspection run by adjusting attitude.  This results in a steady decrease in IAS as they try to maintain the ridiculously low height of fly thru.  Then, at completion of this 'inspection' they require bags of power to recover IAS + climb to a safe circuit height agl.  What you can't determine from 150+ ft agl isn't worth seeing!

 

I'm seriously concerned about where training is heading. We have to improve our pilots handling skills so they don't lose control close to the ground. (RLOC).  We have to impart some basic flying skills which make them safer at lower levels. I also can't see why we are not exposing all RAAus pilots to a couple hours of instrument flight - full or limited panel according to their aircraft.

 

And that's my vent for the week!   Happy days.

 

 

[johnm]

is it the difference of the experienced and non-experienced - that we speak of ................... those pilots that collect wires

 

the non experienced might be at shorter odds to collect a wire, but I think its because of the complacency of a pilot - irrespective of experience

 

from the wire strikes I have read ............. wire strike pilots never even thought of 'wire' till it happened 

 

wonder what the human factor's scenario / question that covers this ?  (no thought - to a danger that is camouflaged - disregarding any issue about flying below 500 ft .............. or between towers / ridge lines etc)

 

 

[facthunter]

 It's often the last flight of the day when the obstacle you knew about all day catches the pilot out. He could have 10,000 hours.

 

  I'd give pilots Unusual attitude recovery, spins and spiral recovery and a good basic low flying run through. You can't plan on a lifetime of flying and NOT find yourself flying low usually without warning at some stage. Some will do it whether they are trained or not. You don't know what you don't know till you are found wanting and that might be too late for you and your Pax.  The dumbing down started in the early 60's  when we didn't have suitable planes to do the training in, so simple ... We just stopped doing it. 

 

     IF Training?  Done in the "unusual attitude" recovery, when you are most likely to need it .Well I did it, like all the others did and it must have saved my life 3 times at least  in the early days so why just for me and my ilk? Nev

 

 

[dsam]

I’ve never forgotten my student pilot days observing a glider (that I was meant to fly in next) try to stretch a final approach above a wire.  Stall and cartwheel was the sad result.  Luckily they survived, but I never forgot the lessons:

1) If you see a wire at the last moment, go under it.

 

2) Under 200 ft AGL on approaches, always expect a (previously unseen) wire.

 

3) Set up your final leg a bit high, and sideslip to steepen the glide angle when near the threshold - especially at unfamiliar fields (or do a precautionary flyover above 200 ft.).

 

 

[Yenn]

I have always found the best way to spot a wire is by looking for what supports it. The shadows cast by poles stand out as straight lines where you would not expect to see them. large spans usually run from hilltop to hilltop, or between two ridges.

 

If you are flying down a valley and below the high ground beside you, then you are really playing with fire.

 

If you have to be below where you could expect to find wires, it would be best to keep low, so that you will see them against the sky.

 

Most of the big wires are shown on the charts and will be obviously between town or cities and power stations. Otherwise you need to keep away from roads and buildings at some distance from roads, that is where the wires will be.

 

Don't forget there is a bureaucrat sitting in an office in Canberra with a map and pondering where he can put a line  in.