O-ring / seals replacement
I get paid the same whether I cut corners or stick by the book.
And that ladies and gentlemen is where this thread should end.
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Thanks Turin. I was nearly killed by a poorly maintained component long ago.Was not an O ring but something equally innocuous. Only the skills of an outstanding pilot saved my life.
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Follow the fricking book an do what it says!
Here is an example of why you should do things by the book...
A platoon of US soldiers were taught to remove bayonets from their M1 rifles by holding the rifle stock and assembly between their legs and using their hands to pull the bayonet off the bayonet stud. They all thought it was stupid doing it this way...why not just hold the barrel with their left hand and pull the bayonet off with their right hand?
So, the platoon went out in the field, fixed bayonets, and charged a nazi held farmhouse in the west of France. Shooting, throwing grenades, and stabbing the odd Nazi with their bayonets...they did well and captured the farmhouse with minimum loses.
Their sargent , who had trained them well, yelled: REMOVE BAYONETS. The men who thought they knew better than the Sargent, all grabbed their rifle barrel with their LEFT hand and pulled the bayonet off the rifle with their right hand.
And all of them reported to sick call with a BURNED LEFT HAND. Why? The barrels were very hot from shooting bullets through them.
The young kids thought they knew better than both the army manual and their sargent.
And you MISTER MECHANIC...if you had known you were going to be fooling around with the filter twice, might have organized the schedule better to save one o ring...but since you didn't...YOU BETTER FOLLOW THE BOOK>
I remember ALASKA AIRLINES thinking they knew better than Douglas how to lube the stab trim jack screw!!! BAMMMMMMM
A platoon of US soldiers were taught to remove bayonets from their M1 rifles by holding the rifle stock and assembly between their legs and using their hands to pull the bayonet off the bayonet stud. They all thought it was stupid doing it this way...why not just hold the barrel with their left hand and pull the bayonet off with their right hand?
So, the platoon went out in the field, fixed bayonets, and charged a nazi held farmhouse in the west of France. Shooting, throwing grenades, and stabbing the odd Nazi with their bayonets...they did well and captured the farmhouse with minimum loses.
Their sargent , who had trained them well, yelled: REMOVE BAYONETS. The men who thought they knew better than the Sargent, all grabbed their rifle barrel with their LEFT hand and pulled the bayonet off the rifle with their right hand.
And all of them reported to sick call with a BURNED LEFT HAND. Why? The barrels were very hot from shooting bullets through them.
The young kids thought they knew better than both the army manual and their sargent.
And you MISTER MECHANIC...if you had known you were going to be fooling around with the filter twice, might have organized the schedule better to save one o ring...but since you didn't...YOU BETTER FOLLOW THE BOOK>
I remember ALASKA AIRLINES thinking they knew better than Douglas how to lube the stab trim jack screw!!! BAMMMMMMM
Last edited by sevenstrokeroll; 6th Jul 2012 at 23:43.
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Their sargent , who had trained them well, yelled: REMOVE BAYONETS. The men who thought they knew better than the Sargent, all grabbed their rifle barrel with their LEFT hand and pulled the bayonet off the rifle with their right hand.
(you've only to read about the sacrificial slaughter....sorry, "diversionary landings" on D -Day to realise that)
Had he trained the men under his command PROPERLY, they'd either
do as they were told or
He would have explained WHY a seemingly stupid and irrational action was mandated.
See any parallel with this thread?
Of course you would comply with replacement of components which were mandated, assuming availability. As stated by many here, there are cases when blind obedience has to be subjugated to experience and skill.
How many perfect seals have been wasted in the pursuit of compliance and at what totally disproportionate cost?
The blanket, ass-covering dogma takes no account of the recency of replacement or the availability of a spare.....caution and prudence have their rightful place , but if blind compliance is the order of the day, watch out, you risk being replaced by less-skilled labour who just do exactly as told.....so why pay out for expensive engineers?
Yes, it's been very interesting to observe the answers and rationale behind this simple job-query.
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but if blind compliance is the order of the day, watch out, you risk being replaced by less-skilled labour who just do exactly as told.....so why pay out for expensive engineers?
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oh please.
if you know that tomorrow you will remove the same piece that you are removing and replacing today, then you can use your imagination and do it all tomorrow.
but if you have removed it and replaced it and removed it again, well you better replace the o ring.
yes, THINK, but think ahead, not behind.
if you know that tomorrow you will remove the same piece that you are removing and replacing today, then you can use your imagination and do it all tomorrow.
but if you have removed it and replaced it and removed it again, well you better replace the o ring.
yes, THINK, but think ahead, not behind.
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Burned hand? Fort Rucker Alabama 1980, Training item Check the pitot heat on an OH 58-
Bat -on
Pitot heat -ON
Amp meter draw. OK
Done
One guy grabbed the little bugger = Hand print & sick call-Some guys just can't learn the easy way.
Bat -on
Pitot heat -ON
Amp meter draw. OK
Done
One guy grabbed the little bugger = Hand print & sick call-Some guys just can't learn the easy way.
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Perrin
I have read this until I finally have to write and agree with cockney steve that the skill that we had (I am another old LAE) is being lost. You are signing for it and
its your choice after taking all the facts on board. I have been in places where they didn't even have oil for the systems so you had to rob peter to pay paul from another system! I know the CAA think we old guys thought we were fireproof but we cared very very much about what we did and I for one always made the right choice, some I got home some stayed a few days but It was up the the LAE to make that call.
Keep them up boys
Peter
its your choice after taking all the facts on board. I have been in places where they didn't even have oil for the systems so you had to rob peter to pay paul from another system! I know the CAA think we old guys thought we were fireproof but we cared very very much about what we did and I for one always made the right choice, some I got home some stayed a few days but It was up the the LAE to make that call.
Keep them up boys
Peter
Last edited by Perrin; 11th Jul 2012 at 16:32.
I know the CAA think we old guys thought we were fireproof but we cared very very much about what we did and I for one always made the right choice,
The LAE is not allowed to make a judgement any more. Those days have gone. Hence the insistance that when certifying any task it has to be stated that it has been carried out using approved data and a reference to the data must be recorded within the text of any log book write up.
Just writing IAW AMM/SRM etc is not enough. Chapter and verse are required or a design deviation with a suitable authority.
We may not like it and it can frustrating as all hell to be sat around with plane full of fidgeting passengers and the crew going out of hours, while you wait for a fax from whereever but that is the modern world.
As has been said you do not get paid any more for cutting corners.
Last edited by HOVIS; 11th Jul 2012 at 09:25.
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OK can anyone explain why 'O' rings have a shelf life (assuming they're kept in the right environment) but once fitted they can go on indefinitely if not removed! Same applies to other rubbery type things.
Last edited by jxk; 11th Jul 2012 at 19:01.
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jxk, not all O-rings have a shelf life. In fact, most of the O-rings we currently use haven't got any limitations.
In my environment, I will definitely stick to approved data and specifications. Why? Because I usually have got an ample supply of compatible and serviceable components. In another environment, it is only fair to deviate from such procedures using both experience and common sense. It is needless to say that any deviation should be documented and corrected as soon as possible.
What does actually frighten me a lot more is the worrying state of some O-rings I have removed. Let's say you remove some accessory and find at least one of the O-rings badly cut and towelled, wouldn't you wonder if this had already happened during assembly?
In my environment, I will definitely stick to approved data and specifications. Why? Because I usually have got an ample supply of compatible and serviceable components. In another environment, it is only fair to deviate from such procedures using both experience and common sense. It is needless to say that any deviation should be documented and corrected as soon as possible.
What does actually frighten me a lot more is the worrying state of some O-rings I have removed. Let's say you remove some accessory and find at least one of the O-rings badly cut and towelled, wouldn't you wonder if this had already happened during assembly?
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re-shelf life. Most rubber compounds react with oxygen from the atmosphere and lose their elasticity or structural integrity (they go brittle/crumbly)
There are, commonly available, many standard -size O-rings, made of different compounds for different applications. but you all know that!
An O-ring in an airtight , evacuated package, will keep indefinitely and should give a normal service-life.
No doubt there are special manufacture ones for aircraft use, specially compounded for contact with the fluids used in aviation. an honest manufacturer of integrity would make it clear that this was a "special" whereas one driven by greedy bean counters would insist that only"genuine" parts are used. (even though many components would be standard stock items.)
not so! At a molecular level, the O-ring can bond to the surface it's in contact with...disturbing the assembly tears the surface and destroys the seal. also degradation , as explained above, can occur.
Most mechanical assemblies need dismantling long before their seals and gaskets reach the end of their service-life. so you see very few perished seals.
There are, commonly available, many standard -size O-rings, made of different compounds for different applications. but you all know that!
An O-ring in an airtight , evacuated package, will keep indefinitely and should give a normal service-life.
No doubt there are special manufacture ones for aircraft use, specially compounded for contact with the fluids used in aviation. an honest manufacturer of integrity would make it clear that this was a "special" whereas one driven by greedy bean counters would insist that only"genuine" parts are used. (even though many components would be standard stock items.)
but once fitted they can go on indefinitely if not removed!
Most mechanical assemblies need dismantling long before their seals and gaskets reach the end of their service-life. so you see very few perished seals.
