Coroner criticises CASA over light plane crash deaths
 

Source: ABC News.

Coroner criticises CASA over light plane crash deaths
The Civil Aviation Safety Authority (CASA) has been criticised at a coronial inquiry into the deaths of two men killed when a light plane crashed in Perth 2003.

Western Australian coroner Alastair Hope has found the deaths of Harry Protoolis and Steven Warriner were preventable.

The two men died after the twin engine Cessna they were in crashed into scrub and burst into flames.

Delivering his findings today, Mr Hope told the court the wrong metal had been used in a replacement part in one of the engines, causing it to fail.

He said it was alarming that CASA had not grounded the aircraft and it was fortunate the problem had not caused other crashes.

He recommended CASA conduct more regular audits of the knowledge of its engineers.

Just saw a news report on Ten about it.

The coroner said CASA needs to concentrate on GA more. He referred to light aircraft as being equal to motorcycles in that they are the most unsafe forms of transport around.

:ugh:

Coronors V Aviation
 

With all due respect, what does a coroner know about safety in GA???

Yes it is true the fatal accidents seem to have been more excessive of late (DS has made that point well known) however I would rather fly in a 35 year old C172 than ride a motorbike accross the country.

Between drugged up truckies (not all of 'em) and people who could not drive out of sight on a dark night, the skies are safer with a PPL'er and a old Warrior, than the highway.

The most dangerous part about flying is driving to the airport!!

Oh hang on this was reported by the media, so maybe that was not what he said or meant.

J:(

Anybody have a link to an actual transcript so we can read what was actually said in court rather than the usual media mutilation?

westaussie...

Distorted accident figures came from ATSB some time ago, and I believe that's where the "motorbike" comparison came from.
In the days when we used to get proper figures, the accident rate of the "private and business" sector was consistently the same as the agricultural sector. In other words the private or business pilots had virtually the same accident rate as the "cropdusters"
Charter flying was considerably safer .

But ATSB saw fit to lump the two groups together and produce a misleading figure, along with the "motorbike anomoly. WHY?

Perhaps what he was trying to say is that this accident, like over 70% of motorcycle crashes, was caused by somebody else.:mad:

Everyone quiet, I think Dick is on the blower to the ATSB and the coroner. It also had something to do with the airspace and they are covering something up. Bloody media and coroner how dare they compare a professional industry with radicals on R1's tearing up the highway.

P.S No hurt meant Dick, all in good fun.:D

I'm not convinced you should discount the findings or a coroner so easily.

If I remember correctly (The ATSB website is broken) the incident was caused by the wrong grade of bronze in a bushing in a fuel pump, which failed as a result.

I wonder what action CASA has taken to find out exactly how this occurred?

There are zillions of types of Bronze and its easy to "turn up" a little bushing. Trouble is, the loadings on aircraft parts are considerably higher than automotive use and the consequences of failure somewhat greater.

I'll except that the consequences of a failure are far greater, but the loads expected on an aircraft fuelpump vs a light truck, car, motor bike, fourby are ecactly the same. what a silly uninformed statement. this is the sort of rubbish that the media latch onto and publish as fact. :hmm:

I know of a few inquests where the coroner's findings bore no resemblance to what someone with a passing interest in Aviation would have come up with - and no, the findings weren't against me.

hehe..

The coroner today also said that powerlines should be better marked around airports, or buried. ABC discussed the option of "sinking" the high voltage line from <bugger, was it Bibra lake to somewhere?!" - the ones that go right past Jandakot> .

P-A-F

PAF, I think they were talking about the high-tension lines from Bibra Lake to South Street, just sinking that section as to sink it all is too much $$$ (as usual)... though I had wondered why there aren't those orange balls on there already like I've seen elsewhere...

Interesting to see they had Chuck from Air Aus on telly, talking about when he put that Robin down at the start of the year (or whenever it was...)

Coroners Report
 

Wait, for the full report.

The Coroner (who, for the record, is a friend) has not been fully quoted.

In the West Australian, his criticism of CASA was about the inability of CASA to provide certification of the LAME or any audit of his reference material and work.

While the Coroner has little aviation experience unlike a Judge of the Court he is able to subpoena experts when he needs advise and this Coronor does, he is not a shoot from the hip type guy.

I would also like a full transcript before questionig his findings.

"what a silly uninformed statement"
Actually its you who are silly and uninformed Wiz.

Unless the original designer of the particular component was a cretin, the bush concerned would have been designed to operate at the maximum allowable pressure velocity (PV) allowable for leaded bronze bearings.

Why? Because the designer needed to save weight. Why do you think the shaft was scored in the first place? An automotive designer would have simply increased shaft diameter and lowered the PV, then you wouldn't care if it was aluminium bronze or leaded bronze since Aluminium bronze actualy has a higher PV than Leaded, but it doesn't do as well dealing with embedded particles as the ATSB report appendix and every machine design manual will tell you.

http://www.bearings.machinedesign.co...mages/fig1.jpg

You must obviously also subscribe to the theory that aircraft parts are way overpriced because they look exactly like their automotive counterparts don't they?

Try telling that to the families of those killed in Helicopter crashes where substitute parts have been used.

I mean a "washer" is just a "washer" isn't it? A "nut" is just a "nut" right? You can replace a wheel bearing with one bought for a few bucks from Repco can you? Try substituting a repco fuel pump for an aviation one and see how long it lasts.

Aircraft are light because the components that make them up are light. As a result loads are higher. To provide the requisite safety factors, the materials, manufacturing processes and quality control is much stricter.

The differences are often very subtle, and in the case of this particular bearing, they were tragic.

Am I missing something here? It was a twin engine cessna wasn't it and one engine caused the crash?. Strewth, that means an aircraft with 2 engines is twice as likely to crash as one with one. Did the coroner request CASA ban all multi engine types?.

Sleeve bearing, Mr Sunfish, sleeve bearing!

What a silly misinformed statement.:*

well, just for you info sunfish, I am in the trade that deals with these matters and I strongly disagree with you. the loads are exactly the same on the parts. they do the same work and move the same distance under the same same pressures and loadings. and yes I do winge at the price of some (not all) parts that are way over priced because they are aviation related.
there are actually BETTER parts available for less money sometimes, because the automotive industry has continued with research and development, unlike the aviation industry. I have seen automotive part numbers that are exactly the same as aviation parts numbers and they are the same parts except the four hundred percent price differance. you would be suprised how many automotive companies supply parts to aircraft manufacturers. next time your pottering about the circuit in your little 172, think chrysler, bosch, Lucas. but thats a whole other story. basically, your statement says that the parts designed for aircraft are of lesser quality due weight saving messures, not that the work required from the part will be any more than normal.

OK, its a sleeve bearing, don't be too picky.

Now Wiz, what I am trying to explain is that automotive designers add extra metal to increase the factor of safety. Wider tolerances and certain types of manufacturing defects are allowed and this then saves money because tight tolerances cost money.

In the aviation design equation, the $ per pound number is higher. this means that the designer will design a part that is close to the theoretical stress limit for the conditions encountered and then use tight tolerances, materials control and so on to ensure that there are no defects.

To put it another way, suppose I have a pin joint that is designed to take an alternating shock load of whatever - say 1000 kg in shear.

The theoretical design size in an alloy steel pin might be say 5mm in diameter with a factor of safety of 4 (ie. ultimate breaking strain 4000kg).

As an automotive designer, my main driver is going to be cost. The conditions under which the pin works are going to include road salt, ice and general crap and the part is buried deep in the suspension so you want it to last the life of the car without inspection.

As a result, I might specify it as nominal 8mm diameter. Since its going to be mass produced by cold forging I'll spec it 8mm -0.00, +0.05 so that the dies can wear to blazes before they need replacing and you can use any old machine to make it. We'll simply cadmium plate it for corrosion resistance and thats the end of it. The surface finish can be as rough as bags because there is now no way the stress is high enough to cause a fatigue crack in your wildest dreams

Now look at the same problem from an aviation perspective. I need a five mm diameter to take the loads with the same factor of safety. The environment conditions lets say are the same.

I can't increase the diameter of the pin because of the weight penalty. That means that any corrosion or manufacturing defects are going to reduce the strength below the factor of 4 that I have calculated is required.

I might therefore choose a high alloy steel and hot forge it. I might then specify an ultrasonic or someother inspection process. I might heat treat it as well.

My dimensions are going to be 5mm - 0.000 + 0.005, therefore I need better quality dies and a relatively new machine to hold the tolerances. My surface finish has to be really good so as not to create stress concentrations that could start a fatigue crack.

If I cadmium plate it then I'm also going to have to add an extra step of baking the finished parts to enure there is no chance of hydrogen embrittlement.

Furthermore, just to be on the safe side you might be required to inspect the pin every 1000 hrs.

Thats where all the extra costs go.

To put it another way, a 5mm pin for aviation use may well have a load rating four or more times a 5 mm automotive pin would have - and you can't tell just by looking at them. You have to know the material, heat treatment, surface finish, tolerances - the lot.

CASA makes this point in relation to wheel bearings - automotive ones sometimes even have the same part numbers, but there are a stack of ABEC bearing grades and Aviation uses the Lower 9high quality) ones.

Same with gears - aviation requires AGMA Class One Gears. You will need a million dollar Zeiss CMM plus some very sophisticated software from Gleason to even tell the difference between class one and two.

Having said all that, I still feel for the poor bastard who specified the wrong material. It would be an easy mistake to make.

I do take your point about modern automotive quality being excellent and producing better than aviation quality. It's true in a lot of cases, for example automotive sheet metal componentry is much more accurately made than aircraft sheet metal, although the industry is catching up.

Now I'm waiting for someone to get picky about something.

Yep....OK.....Uh huh..???:confused: :confused: :confused: