Man killed at four-wheel-drive park

**p38arover** · 7th April 2008, 12:59 PM

Originally Posted by JDNSW

Like every accident, there was a chain (no pun intended) of events, and breaking the chain anywhere would have prevented the death.

There is a description for this. The James Reason Model - sometimes called the Swiss Cheese Model. See Colorado Firecamp - HFACS, the "Swiss cheese" model, Introduction

The concept is that

In the Swiss Cheese model, an organization's defences against failure are modelled as a series of barriers, represented as slices of Swiss cheese. The holes in the cheese slices represent individual weaknesses in individual parts of the system, and are continually varying in size and position in all slices. The system as a whole produces failures when all of the holes in each of the slices momentarily align, permitting (in Reason's words) "a trajectory of accident opportunity", so that a hazard passes through all of the holes in all of the defenses, leading to a failure

If any single item changes, the incident is prevented. We use it at work, and I believe the aviation industry also uses it. It is an excellent concept.

**JDNSW** · 7th April 2008, 01:08 PM

Originally Posted by p38arover

There is a description for this. The James Reason Model - sometimes called the Swiss Cheese Model.

Yes, I am familiar with this from aviation. It is even better than analysing accidents as a chain of circumstances because it can consider equally a wide range of factors that may not appear to relate to the investigation until you look at what could have happened if other holes had lined up. It makes complete nonsense of the idea that accidents (or indeed any other event) have a single cause. Thanks for the contribution - being limited to dial-up I did not even think of trying to explain this model without pictures!

John

**p38arover** · 7th April 2008, 09:40 PM

Originally Posted by Dave_S

The news report says the vehicle was on an "extreme" track. That word has become so over used in advertising and lifestyle descriptions that these days you can get just about any product you can think of with "extreme" written on it.

One has to take media reports with a grain of salt.

This report about the death of my son had a number of inaccuracies. The journos just don't have all the facts when they write the stories:

Motorcyclist dies near Tumba - Local - General - The Daily Advertiser

**29dinosaur** · 8th April 2008, 07:26 AM

Originally Posted by p38arover

One has to take media reports with a grain of salt.

So true - 2 separate local accidents this week witnessed by friends .... Local paper (and Sydney TV news channel) had both accidents totally distorted. The local paper was unintelligible as to what was written and what actually took place. Makes one rather sceptical about any news report about any subject... but there must be - must there not, some which are true to what took place, or am I only dreaming??

**Dave_S** · 8th April 2008, 07:50 AM

I totally agree with your comments on the media. I'm always astonished at the ability of so called journalists to report anything but the truth. They do work to very tight deadlines, but generally they behave like pigs at the trough of sensationalism. They have to write stories which sell advertising (or some other agenda) and the facts are usually not enough.

**Diego Luego** · 8th April 2008, 10:08 AM

Any 4WD novices should read and heed the advice given in this thread. Recovery and winching can be the most dangerous thing you will ever do.

Chain can snap without warning, and wire can literally cut you in half. Keep onlookers out of the way. One time I used my winch a stupid photographer wanted to video us standing between the vehicles, and was annoyed that I wouldn't continue until he was more than a wire length away.

**CraigE** · 8th April 2008, 02:24 PM

We have been using the swiss cheese model in the mining industry for some time as well. Not always foolproof.

Originally Posted by p38arover

There is a description for this. The James Reason Model - sometimes called the Swiss Cheese Model. See Colorado Firecamp - HFACS, the "Swiss cheese" model, Introduction

The concept is that

If any single item changes, the incident is prevented. We use it at work, and I believe the aviation industry also uses it. It is an excellent concept.

**CraigE** · 8th April 2008, 02:29 PM

Originally Posted by JDNSW

Like every accident, there was a chain (no pun intended) of events, and breaking the chain anywhere would have prevented the death. Just to note a few links in this chain:-

1. Putting the wheel over the edge in the first place.
2. Use of chain in an unsuitable application.
3. Failure to use a safety line in case of the chain breaking
4. Failure to use a seat belt.
5. Perhaps use of unrated chain or fittings or use of unsafe towing points (if these rather than the chain gave way)

And so on. My point is that you cannot say, with this, as with any accidental death, that there was a single "cause" and concentrate on it to the exclusion of the other links in the chain - in the next case, that particular link may not be present, but the one(s) ignored in the present investigation may have been just as important (although in this case, from the quoted reports, the use of chain and failure to wear a seat belt would seem to be the most important factors).

Chain actually has the advantage over other materials that it does not have much give, so that injury or damage from released strain (on breakage) is unlikely, as well as being very difficult to cut against rocks etc. But as pointed out, for vehicle recovery where shock loads may occur, and the possibility of the vehicle or anything else falling, it is not a good choice, although it may be good, for example, with a vehicle bogged on flat ground, and is definitely the choice for e.g. snigging strainer posts.

John

John,
spot on. Appropriate use and shock loading of chains or for that matter wire cable is not ideal. I have seen some pretty ordinary chains and dedicated lifting chain at that elongated, worn or even break and cables do the same.
This is not even considering if it was just harware store chain which is scary. You would have hoped one of them would have had some knowledge or a strap.

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