Wire strike protection?
Thread Starter
Joined: Mar 2011
Posts: 18
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From: Japan
How effective is a wire strike protection installation when a helicopter flies into a power line or telephone line at speed?
What are the general limitations of such systems eg, max wire thickness?
Does anyone perhaps have photos of a helicopter that survived such an incident?
Im actually looking for photos of helicopters that have had WSPS installed, and then had an incident where the system worked as intended.
The pix on those two links and most of the ones I can find appears to relate to accidents without WSPS.
Thanks for any help!
What are the general limitations of such systems eg, max wire thickness?
Does anyone perhaps have photos of a helicopter that survived such an incident?
Im actually looking for photos of helicopters that have had WSPS installed, and then had an incident where the system worked as intended.
The pix on those two links and most of the ones I can find appears to relate to accidents without WSPS.
Thanks for any help!
Joined: Jul 2004
Posts: 816
Likes: 5
From: Home
It's called HELLAS. German border police has it.
Apparently 50 units in operation world wide.
Go to 34:00 in this report. Seems to be working nicely.
Die fliegenden Hightech-Cops - Die Reportage XXL - N24.de
Apparently 50 units in operation world wide.
Go to 34:00 in this report. Seems to be working nicely.
Die fliegenden Hightech-Cops - Die Reportage XXL - N24.de
Joined: Sep 2003
Posts: 2,081
Likes: 189
From: Redding CA, or on a fire somewhere
Joined: Jul 2010
Posts: 76
Likes: 0
From: No longer in the sand box
Try this link.
I have seen firsthand how well the system works. Up to 3 wires the size of your thumb is the reported ability.
Cheers
I have seen firsthand how well the system works. Up to 3 wires the size of your thumb is the reported ability.
Cheers
Joined: Jul 2005
Posts: 273
Likes: 0
From: Spain
...
It's a good question but complicated answer,
Mostly additional weight and expense if you question honest management. (if you can find any)
They are a good proposition in certain applications, for an example where you have pilots flying somewhat standard tasks such as charter in flatlands, corporate/VIP where you're not landing anywhere very challenging but might land in a yard where someone just installed a SWER since last time you were there, and forgot to mention it etc
But: Many transmission conductors are too large to cut (18-29mm) steel reinforced (most small gage are aluminum) and we don't have the mass or speed for the cutter to work correctly.
Landing in moraines or toe-ins to steep terrain etc, the bottom cutter can be a real danger. (I swapped ships one time back in the early 90's and forgot it had the cutters installed and nearly flipped the 212 over when it caught on a rock sticking out of moraine debris). We then removed the bottom cutter blade, but our PMI (principle maintenance inspector) said the STC was all or nothing, so we pulled the system out...
Personally I don't like them for utility ops, where logic would suggest they're most needed. But I can see the merits for other types of work...
Naturally, if I'd survived a wire strike because of a WSPS I might feel differently...
170
Mostly additional weight and expense if you question honest management. (if you can find any)
They are a good proposition in certain applications, for an example where you have pilots flying somewhat standard tasks such as charter in flatlands, corporate/VIP where you're not landing anywhere very challenging but might land in a yard where someone just installed a SWER since last time you were there, and forgot to mention it etc
But: Many transmission conductors are too large to cut (18-29mm) steel reinforced (most small gage are aluminum) and we don't have the mass or speed for the cutter to work correctly.
Landing in moraines or toe-ins to steep terrain etc, the bottom cutter can be a real danger. (I swapped ships one time back in the early 90's and forgot it had the cutters installed and nearly flipped the 212 over when it caught on a rock sticking out of moraine debris). We then removed the bottom cutter blade, but our PMI (principle maintenance inspector) said the STC was all or nothing, so we pulled the system out...
Personally I don't like them for utility ops, where logic would suggest they're most needed. But I can see the merits for other types of work...
Naturally, if I'd survived a wire strike because of a WSPS I might feel differently...
170
Purveyor of Egg Liqueur to Lucifer
Joined: Nov 2002
Aviation Qualifications: ATPL
Posts: 4,752
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From: Alles über die platz
So tell me why wire strike protection isn't on all helos?
Safety Study of Wire Strike Devices Installed on Civil and Military Helicopters
http://www.tc.faa.gov/its/worldpac/techrpt/ar0825.pdf
Summary of the findings of the wire strike warning and protection systems:
•The WSPS is most effective when the helicopter impacts the wires nearly perpendicular to the wires in a level attitude and at flight speeds of more than 30 knots.
•The WSPS is available for about 25% of the helicopters.
•The WSPS is most effective when the helicopter impacts the wires nearly perpendicular to the wires in a level attitude and at flight speeds of more than 30 knots.
•The WSPS is available for about 25% of the helicopters.
Page 25, Table 8. Helicopters Involved in Wire Strikes
Thus, nearly 74% of the helicopters involved in the wire strikes could not have been fitted with wire cutters.
Joined: Aug 2006
Posts: 505
Likes: 1
From: Wiltshire, UK
The bottom one can get in the way of nose mounted cameras
I can think of quite a few nose mounts that avoid the lower cutter, but maybe you brief your pilots to fly under the wires so the top cutter can get them.
Joined: Nov 2003
Posts: 1,937
Likes: 28
From: UK/OZ
I can think of quite a few nose mounts that avoid the lower cutter
Incorporating a cutter into nose mount hard point (the so called sharks fin on AS 350 single pole mounts) would be a help, because the area between camera pole and nose of the chopper is a natural trap for wires that slide down the windscreen.
Any stats on the number of occurrences, without wire strike kit of where the wire bites, is it mast or skids/crosstubes?
Mickjoebill
Last edited by mickjoebill; 20th February 2012 at 23:28.