Chinook Power Line Strike Wales

[NutLoose]

Yes that awakens a sleeping brain cell and sounds like it.

[msbbarratt]

Originally Posted by bspatz

From the eye witness account it seems that the chinook was already making an emergency landing before hitting the wires so it is seems to me understandable that such an unplanned event would increase the likelihood of hitting wires.

Pulling off an emergency landing which also involves a brush with wires? Sounds like a "well done" + a big scotch for the jangled nerves is in order.

[NutLoose]

Originally Posted by pba_target

Absolutely, and detecting unpowered wires is definitely where it's at for a variety of reasons. However, even that link only describes spotting domestics 1000' away. Better than nothing for sure, certainly at slow speed on the approach or nap of earth, but if you're at 50'/120kts it's not going to save you from a set that are strung. 1000' equates to 330m approx - that's about 5s out from the wires if I've got my maths right?

There's a lot of room for technology in all of this, but two things are key - how do you present it to the crew and how do you prevent it from going off continuously with false alarms or otherwise.

Both of those are turbo challenging and I'd be the last to say I know what the answer is. Active detection has advantages over database systems for sure, especially in operational flying, but false alarm rate will get you killed through alert fatigue just as well as not having the system. I do know that we've been preaching "look out the window, clear your flight path and fly defensively" since Pontius was a pilot, and people still clatter into wires though!

The advantage of LIDAR is it also cuts through vegetation and shows the terrain as it is.
Many of the archeological programmes on the TV these days use it to physically map terrain through trees etc so they can see disturbances in the ground layer. You would think someone would have exploited it now sufficiently to make it a viable asset.

[Misformonkey]

Eye witness accounts tend to be a little off the mark as the Clutha accounts would suggest.

[Thud_and_Blunder]

dogsridewith: the answer appears to be yes; the company which owns the powerline had one of its helicopter crews re-stringing the span the following day, as can be seen in the Forces TV video.

[OvertHawk]

Originally Posted by Thud_and_Blunder

dogsridewith: the answer appears to be yes; the company which owns the powerline had one of its helicopter crews re-stringing the span the following day, as can be seen in the Forces TV video.

Even if the wires had not been broken they would still have been replaced after an event like this.

[[email protected]]

Interesting rumour that the crew were stunting and bunting over Chivenor earlier in the day.................

[ShyTorque]

Originally Posted by charliegolf

Shy, was that the little circular display by the pilot's right knee, with green lights indicating the quadrant the wires were in? Seem to recall that being trialled, and it not being very trust-inspiring at all.

CG

I don’t recall green lights, only the daisy petal display.....but it’s over 40 years ago.

[Tankertrashnav]

I remember a while back we had a thread about anxiety dreams among aircrew. Many contributors to the thread were surprised that they weren't the only ones who had a recurring dream about flying very low, often along a street, and always under wires. Its certainly a dream I had many times when I was flying.

I forecast a lot of disturbed nights among those have been following this thread. My only comment about this accident is that I am amazed how tough those windscreens are, and how bloody lucky the guys were.

[Vendee]

I guess the damage to this Chinook will be repaired fairly easily but this isn't always the case for wirestrikes. A few years ago, Apache ZJ202 out of Wattisham hit a HT cable in the local area. The physical damage wasn't too bad because of the Apache's wirecutter system. A spokesman for 16 Air Assault Brigade said: “The Apache has sustained minor internal damage and will be moved to Wattisham, by road.

But the HT voltage from the cable fried the aircraft's electrical system and welded the main undercarriage cross tube to the airframe. ZJ202 never flew again.

[500 Fan]

Originally Posted by Distant Voice

A 2013 paper covering the MoD Helicopter Safety Enhancement Programme stated,

There is currently no wire cutter kit developed for the Chinook and there are no known plans to develop one. The cost and timescale associated with introducing this capability suggest that an alternative means of protecting the aircraft against wire strike may be a better option. Assessment of a tablet based moving map capability is underway, which would have details of known wires and obstacles overlaid. The key to this type of system is considered to be an effective means of alerting the aircrew to the presence of wires without them having to spend prolonged periods “eyes-in”.

I hope the ODH found suitable mitigation to cover the wire strike risk when he signed off on the ALARP safety statement.

DV

There was a wire-strike kit proposed as part of the equipment fit for the HH-47 proposal for the USAF's CSAR-X competition. Forward of each landing gear leg was situated a wire-cutter. It looks like another wire-cutter was situated under the nose. The CH-46 also had a wire-strike kit fitted during its later years in service but as mentioned above, blades fitted over the windscreen might not have been possible. It is odd that no kit was ever put into use on the Chinook.

500 Fan.

[Tashengurt]

I'm amazed that something so apparently simple as a wirecutter can be less desirable than a software system that seems to be less than proven.
I would have thought both would be the ideal with the cutters as a minimum and a fail safe for those pesky undetected wires.
Obviously I'm missing something, why isn't it as simple as just bolting cutters on?

[dead_pan]

Originally Posted by Tankertrashnav

My only comment about this accident is that I am amazed how tough those windscreens are, and how bloody lucky the guys were.

I understand the 11kV cables aren't actually that strong and can be severed relatively easily e.g. if a tree fell on them. The lads who moved a set of these cables running near our property used a simple set of ratchet wire cutters (they're only c.0.5" in dia).

[Green Flash]

Originally Posted by Tashengurt

I'm amazed that something so apparently simple as a wirecutter can be less desirable than a software system that seems to be less than proven.
I would have thought both would be the ideal with the cutters as a minimum and a fail safe for those pesky undetected wires.
Obviously I'm missing something, why isn't it as simple as just bolting cutters on?

I used to live next door to an engineer whose job was to work out the placing of wire cutters on the Merlin. One of the biggest probs was working out the stress paths through the airframe depending on where the cutter blades were mounted. I recollect his team spent a year crunching numbers. I dont think its one of those parts of an aircraft you can test for real (unless the test pilot is willing!)

[Mogwi]

Originally Posted by Tankertrashnav

I remember a while back we had a thread about anxiety dreams among aircrew. Many contributors to the thread were surprised that they weren't the only ones who had a recurring dream about flying very low, often along a street, and always under wires. Its certainly a dream I had many times when I was flying.

And there was me thinking that I was the only one to have that dream!

mog

[Herod]

Nope, not the only one, although mine started when I left flying, following a nervous breakdown. Strange thing, the brain.

[HarryTBasher]

Originally Posted by [email protected]

Interesting rumour that the crew were stunting and bunting over Chivenor earlier in the day.................

Rumours are almost always wrong, and with your experience you should know the damage you can do by posting completely unsubstantiated cr@p like this on a thread like this.

[high spirits]

Originally Posted by [email protected]

Interesting rumour that the crew were stunting and bunting over Chivenor earlier in the day.................

I happen to know that they weren’t. So don’t be a massive bellend all of your life and stop making stuff up.......

[[email protected]]

A colleague has a house that overlooks Chivenor and his son is an aviation spotter - he told his dad what the Chinook was doing.

You can start with name calling if it makes you feel clever but the Catterick crash started with 'high spirits' and 'interesting flying manoeuvres' and ended in tragedy. If the lessons still haven't been learned and the wire strike was the same flight as the one my mate's lad saw then getting it out there is the best thing to do to prevent another poorly disciplined crew taking other people with them.

It may not have been connected with the wire-strike flight at all and everything may well have been squeaky clean and above board - perhaps the SI will answer those questions.

[meleagertoo]

Well I went through a single 11KvA line in a 1500lb Enstrom at 30Kts and the line just snapped with no damage whatsoever to the airframe. Stopped us dead though. Thank goodness Enstroms are so tough...
The damage to that c. 40,000lb wokka looks like much, much heavier cable so likely a triple 33KvA line plus at that angle of bank on a normal 11KvA pole line would make a catastrophic ground- tip strike almost inevitable. OK'it might have been spanning a valley - who knows, but the sawing effect of the cable suggests it was a pretty substantial one and rather higher than a normal 11KvA line.
Additionally a wirestrike that had that effect on the cockpit at that aob must have got involved with the rotorblades too so expect substantial blade damage. Is some of that visible top right in the first photo of this thread?

Either way for a wokka to get that close and personal to electrical grid pole lines (I have several hundred hours inspecting these) something wasn't going according to brief, that's for sure.

Lucky blighters!
Tough machine.