Powerline maintenance helicopters
 

Non pilot here.
Yesterday Discovery Channel (as best I recall) showed a program about powerline maintenance in the USA. This program included hair raising material showing the use of helicopters to convey maintenance technicians into place - actually working off the skids on lines at 500Kvolts. At some points the tail rotor appeared to be about a foot from the lines. The whole rig is attached to the live line by a cable during the maintenance after initial connection via a wildly arcing wand...

During the course of the program the crew being filmed were actually called to a site where a previous 2-man crew (pilot & technician) had just been killed in the course of the same work.

Next to bomb disposal, this takes my prize for br@55 b@ll5. Anyone here actually done it? And wouldn't it be better to use a helicopter with a shielded/enclosed tail rotor?

Phew, rispeck!

The Hughes 500 is just the best machine for the job despite the tail rotor being on the line side. If done correctly, the tail rotor should not get closer than about 5 feet from the line at any time. A fenestron would be nice but the EC120 is underpowered for this job and everything else is just too expensive. Bell 206 series helicopters do work well and the tail rotor is farther away from the line but then you have longer and higher main rotor blades when working between the earth / shield wire and the conductors so less clearance, the 500 is better.

The crash they went to was of a helicopter involved in powerline patrol that flew into wires, not the same company or same work and just coincidence that it happened at that time, sad though it was.

Overall, the work is challenging, rewarding and some of the best flying I have ever done.

Do not do live line repair--but have many hours patrolling for WAPA:

http://i76.photobucket.com/albums/j3...at/Layla/2.jpg

I just watched the documentary on Discovery this afternoon. I think they're all certifiable - bad enough sitting on the heli skids while working on live 500,000 volt powerlines but water washing the live insulators from the helicopter is :eek:

Absolute nutters, no risk assessment I've ever seen would let them do what they were doing.

There is a risk assessment, it is a job, and the risk is mitigated for that particular job. I have not done live drops of people, but do sling them tools after they have climbed up, and have also set poles... There is always a tail gate brief and all aspects of the job are discussed. This is all in a days work for some, and I guess it comes down to what you feel comfortable with.

Does anyone in the UK powerwash live 500,000 volt insulators using a helicopter?

Paxman

Nope because: -
1/ our maximum transmission voltage is 400,000 volts

But more seriously

2/ the only live line operations approved, by any means, in the UK are at up to 11,000 volts from insulated "cherry pickers"

Helicopters are used for line patrol and load lifting in dead line situations

Ppruner AirWon does this for a living and was one of the pilots in the programme.

So let me get this right, water and electricity don't play well together? I knew that tingly feeling wasn't just me arthritis playing up again.....

Hats off to Airwon, there's something in my brains logic that says you just shouldn't mix water and electricity.

From the programme it was clear that Air2 take the safety of their ops very seriously but it's interesting that the UK and US seem to have different interpretations of what's allowed on live o/h lines.

I wonder if in the UK they're allowed to powerwash live 11kv insulators from the cherry pickers? I'd be surprised.

Well the company I work for is also the water utility & we get on alright!

I do recall that insulator pressure washing has been done in the UK at ground level, if the conditions are controlled (especially the water quality) it is not difficult.
From a helicopter as there is no connection or contact to earth the risks (electrically) are far lower, any electrical charge picked up by the machine is not a problem as the whole machine would be live at the same voltage.

(just as birds sat on powerlines don't get fried - same principle)

There are two previous threads on this, complete with videos, worth looking at:

I don't give 2 hoots and a holler about flying inside a helicopter

Danger Men: UK TV Channel 5

:ok:

The water used for insulator washing is demineralized. Demin water prevents conductivity so does the wash boom. At no time does the aircraft become energised when washing insulators.
Live line platform work and insulator washing is very safe as long as you follow the procedures that are in place for such operations.

Pure water does not conduct electricity.I beleive Faraday used demin water as a dielectric in some of the capacitors he made.Could be wrong though (about Faraday) but thats what we were taught in physics 45 years ago.

The water used for insulator washing doesn't have to be demineralized, the conductivity just has to be below a certain level. Tap water is often suitable. There is a risk of the current passing through the helicopter (and occupants) if the gap between the conductor (wire), the aircraft and the ground (or tree), or between the aircraft and 2 conductors isn't sufficient. The spark will jump the gap, pass through the helicopter and jump to the earth or other wire. An Aussie machine got zapped a couple of years ago. Linesman knocked unconscious, pilot injured and aircraft damaged. A linesman in Australia was killed a few months ago doing live line work when the aircraft M/R clipped a wire.

Can anything replace the 500 for line maintenance?
 

Just a couple of questions in relation to the use of the MD500 in line maintenance work.

1. Is there any other type that can replace the MD500 in the line maintenance role, particularly in the use of the mainteance platform for the line-man?

2. Will Haverfield/Agrotors simply replace their older 500Ds with new-build 500Es?

3. The dominant version of the 500 used in line-maintenance work seems to be the D model , with a handful of E models thrown into the mix. Is there an reason why the MD530FF is not being used for this type of work?

4. If the 500D was still in production, would it sell better than the 500E to operators like Haverfield and Agrotors for such specialised work?

Thanks.

500 Fan.

Line work 500d/d/e/f
 

The 500 series is a great machine due to it small MR disc dimension, excellent visibility for pilot and sensitive (but not over sensitive) control. It also has a relatively short tailboom and thus not as prone to momentary weathercocking with wind gusts.
This makes it a very stable platform for this type of work, as for using a E model or indeed an F model there is no benefit, with the kind of payload used in this role neither a more powerful engine or indeed as in the f model a beefed up main transmission is of any use.
For line work the D model is fine and it's lower fuel consumption gives a much better loiter time and lower running costs.

How appropriate it must be then that you are not associated with that operation!

MD's vs the rest...
 

Skywork in New Zealand use B3's. Would be interesting to hear how this machine compares to the MD's? Simplex in the US have also been trialling a wash-rig on a Bell407...so the MD's aren't the only viable options.

KS

Horses for courses
 

Spray washing, -
probably easier in a AS350 - higher load capaicity,bigger tank, longer loiter.

Line man work -
H500 for reasons below.