...and this is why we all love aviation in Australia. You need to be a talented linguist and a sharp lawyer to even agree that you are allowed to commit aviation.

I wonder if on the Professional Lawyers Rumour Network they have an aviation section?

A new piece of paperwork out of CASA that has the potential to cause some headaches: AWB 51-008.

(Extracts)

Effectivity
All aircraft that utilise tubular steel structure that is or forms part of the primary (or secondary) structure of the aircraft

Aircraft operators should ensure that the maintenance program for an aircraft constructed from welded tubular steel structure includes a requirement to periodically inspect all external and internal surfaces of the tubular structure. Any approved maintenance program which does not include a periodic inspection that will detect corrosion in the structure may be considered inadequate

(Emphasis mine)

If an appropriate inspection technique or NDT procedure is not available in the existing approved data for the applicable aircraft, such data may need to be developed by an NDT specialist in conjunction with a CASR 21M Delegate.

I wonder whether an engine mount is a primary or secondary structure? I would have thought so. Do aircraft have inspection techniques or NDT procedures in existing approved data that will detect corrosion on the internal surfaces of the engine mount?

Not to mention the effect on the presumably intended targets, where the fuselage etc. is welded steel tube.

How much weight does a "recommendation" in a AWB carry?

A story behind the AWB

Yes I understand the problem.

However I wonder whether it was necessary to declare potentially most/all current approved maintenance programs inadequate, and whether NDT procedures really need to be developed for each aircraft by a NDT specialist and CASR 21M Delegate.

Interesting... the one I was referring to is Issue 2. Issue 1 seems more reasonable.

Issue 1:

CASA recommends that if engineers or aircraft owners are concerned about
and / or suspect possible internal corrosion on tubular structures to consult with a specialised NDT person

Issue 2:

Aircraft operators should ensure that the maintenance program for an
aircraft constructed from welded tubular steel structure includes a
requirement to periodically inspect all external and internal surfaces of the
tubular structure. Any approved maintenance program which does not
include a periodic inspection that will detect corrosion in the structure may
be considered inadequate

"Periodic" is concerning....once every fifty years? Not!

To be sure, I am not familiar with the full suite of CARs for maintenance. There would have to be some sort of trigger to progress to NDT using X Ray examination. The case in question would indicate...corrosive environment, drains blocked or open to atmosphere, integrity of structure indicates weaken of joints..rather than a calendar date in service.

This will morph into X-ray inspection of engine mounts every Two years.

Just like the first blowie reminding us that summer is on the way, an AWB is a signal of an impending AD.

The dead giveaway is the buzzing in the background getting louder: you noted the difference in language between Issue 1 and Issue 2.

This is what happened with stainless steel terminated cables. The AWB morphed into an AD. Having demonstrated how well industry has learned to be helpless - the cable AD was met with little more than a shrug of resignation from the industry - CASA is moving on to primary and secondary tubular steel structures.

The way I read it, if there is not something already in the approved data for the particular aircraft, the operator is expected to pay a NDT specialist and CASR 21M Delegate to develop a program of periodic inspections.

Presumably they would set the intervals for inspection.

My gut feeling is CASA bit off more than they intended here. I doubt it was intended to include all aircraft, but I can't really see that you could claim the engine mount was a less important structure than e.g. the tail spring mount.

My response would be to buy a new engine mount

That doesn't solve the problem of an "inadequate" maintenance program.

CASA is incapable of building an "adequate" maintenance program. Comprehensive? Expensive? Both yes. "Adequate"? No.

For me, an internal wash with epoxy primer is adequate, coupled with a design that is fail safe or now " damage tolerant" so that blind Freddy can see he has a problem before bits fall off.

To put that another way; remind me how many corrosion related catastrophic failures of welded tubular structures have we had compared with all the other sources of accidents?

Sunny, all those tubular structures were clearly inadequate …..in 100% of fatal accidents the tubular segments all failed. They must be dangerous!!! :}

Jaba,
Careful, you might give some of the militants in CASA ideas.

Seriously, in this day and age, there are better things than linseed oil to fill tubes after welding. Having had some experience in such things, I would not go for a hard coating, but any one of a number of the coatings that are both a mechanical barrier to moisture, and have anti-corrosion properties.

Tootle pip!!

. Having had some experience in such things, I would not go for a hard coating, but any one of a number of the coatings that are both a mechanical barrier to moisture, and have anti-corrosion properties.

Omg. You are God. Knowledge of all. Master of all you must be god.

This is something I know a lot about. Even had this point in Court brought up.

How funny. Is there anything you don't know leadie.


Tootle pip!![/QUOTE]

yr write;


Are you stalking LeadSled?

nope not at all. He is very entertaining don't you think. I think he should head Casa be the PM and how about state prem as well. Head Easa may be FAA and maybe NZ Caa as well. Head the the law department and may be write the exams for aircraft maintenance. He could run a course on LOP and how to fill out a M/R as well.

But no I'm not.

Yr' wrong,
Why don't you tell us all what is, engineering wise, incorrect in my last post.
Fact is, you think you know about my background and experience, but by your posts, continually illustrate you have no idea.
Tootle pip!!

PS: As it happens, been there, done that.

Quite frankly your arse is jealous of what comes out of your mouth.

Your statement on linseed oil for a start. Do you know why that is used. So how many m/r have you issued oh that's right zero nil nada but your an expert on that. And btw I know lots about yourself. People only to happy to talk about your self. Blah blah.

So please tell us how you cam manufacture a window and install it. Still not done that.

yr' wrong,
Go back to the ATSB report on a previous post on this thread.
I stand by my statement that, in this day and age, corrosion prevention in tube frames has come a long way since linseed oil.
Tootle pip!!

PS: Has it ever occurred to your tiny mind that 4130 tube frames are not limited to aircraft, I built my first one before I was old enough to vote.