Quiz - What's wrong with this Gascolator installation?

[jfogarty]

Good point Scott, I knew I installed the gascolator for some reason. Thanks.

Jim Fogarty
RV-9A Flying

[jetjok]

Originally Posted by jrs14855

Copper tubing was used extensively by light aircraft manufacturers well into the 50's maybe later. Perhaps most commonly found on Pipers. Nearly all the Piper hoses, lines fittings etc in the 40's and 50's was non aircraft.

True dat! With respect to the fuel line plumbing on my 1950 PA-20, the local auto parts store has become my best resource! I have always wondered if someday I should change it over to AN fittings? But, then again it has been working for 65 years!
All the primer lines are indeed copper, and I have only had one broken line in the 12 years that I have owned the plane. This is likely due to the fact that all the lines are very well secured to prevent vibration.

[rmartingt]

Originally Posted by Danny King

There is a lot of grandfather worship in what some builders do.

That's not exclusive to homebuilts--give the systems parts of the certification standards a good read sometime.

I think what happens is that someone comes up with a good/simple/effective way of doing something on an airplane, that's better than other ways that are feasible within the limitations and assumptions valid at that time.

Over time, especially if the pertinent technology is relatively stagnant, that way of doing things becomes the de facto industry standard, maybe even becoming part of the certification standards. If the underlying assumptions don't change for a while, people and industry gradually forget the reasons why it became the standard in the first place--"this is the best way to do it right now" becomes "this is the best way to do it", which in turn becomes "this is how it will always be done".

That's all well and good so long as the assumptions and conditions continue to hold true. But when something comes along that changes or invalidates those underlying assumptions--whether it's new knowledge/understanding, or a new/better technology, or something else--you have a problem. Sometimes it's a regulatory issue--a really simple example is 23.1557, which requires all "reciprocating engine-powered airplanes" to have their fuel filler openings marked with the word "Avgas" and minimum grade, which was great when all piston airplanes burned avgas exclusively. But these days, not all piston-engine airplanes do--if my airplane has a diesel engine and therefore runs on diesel/Jet-A, I've got a problem, albeit one that is relatively easy to get around.*

Now that's a simple example, but when you start looking at more complex things related to avionics, or to engine control, the waters quickly get muddier and hotter. In the interest of civility I'm not going to get into specifics, but I'm sure all of us here can think of cases where an older, established practice has been put up against a newer one. I'm not saying that the new practice/method/technology must necessarily be better--I just ask that, before immediately falling back to the older "proven" practice by default, take a moment to ask yourself a couple of questions: Why did this method become the standard? What made it better than the other ways? What things were taken for granted or assumed then that aren't now? What has changed between then and now? and If I didn't know about this older way, and was trying to start from scratch today, how would I do it? Do some research if you have to. If you really sit and think about it, and answer yourself honestly, you might change your mind. Or, maybe you won't. Either way, you've learned something And now, you're making an informed choice rather than blindly adhering to the past or slavishly following the latest trend.




* I bring this example up because it's one of the many things we've run into in the ASTM groups looking at the new Part 23 standards. It was relatively easy to fix, but we've run into a whole bunch of situations where the question to the FAA participants of "well, why is that the rule? It doesn't make sense/is outdated/is based on assumptions that aren't valid any more" is met with answers like "well, when we wrote the rule 40 years ago nobody imagined there would be another way to do it" or "well, we don't really know why it's the rule, but we're sticking to it". Nobody has been able to explain to any degree at all why position light lenses need to be "flameproof" but landing lights need only "not present a fire hazard", but they won't consider changing it, either.

[Pat Stewart]

Multiple issues that have all been identified above but I would add the fact that it has one at all.

Oops, I just noticed Danny had already made this point.

[Walt]

I think the main point I'd like to see folks take away from this is that every time you do an inspection, especially if you're looking at your own aircraft, is that you really need to take a step back and try to look at things with a "fresh set of eyeballs".

This aircraft was built in 1992 and I have no idea when this part was actually installed, but I can assure you it wasn't recently so it has been overlooked for quite some time.

This is an excellent example of how having someone else do your condition inspections every now and then can be a good thing, owners/inspectors will get complacent if they see the same aircraft every year, it's just human nature, they stop looking like it was a first time inspection which always has a higher level of scrutiny than a repeat aircraft. Builders are especially vulnerable to this type finding, they "know" they built it correctly so why would they need to scrutinize it?

Your life and those of your passengers depends on sound maintenance practices, make sure you give it the time and attention it deserves!

[Mel]

Good post Walt. I couldn't agree more!

[rvbuilder2002]

And I emphatically agree with Mel's agreement.

[mannanj]

Originally Posted by Walt

I think the main point I'd like to see folks take away from this is that every time you do an inspection, especially if you're looking at your own aircraft, is that you really need to take a step back and try to look at things with a "fresh set of eyeballs".

This aircraft was built in 1992 and I have no idea when this part was actually installed, but I can assure you it wasn't recently so it has been overlooked for quite some time.

This is an excellent example of how having someone else do your condition inspections every now and then can be a good thing, owners/inspectors will get complacent if they see the same aircraft every year, it's just human nature, they stop looking like it was a first time inspection which always has a higher level of scrutiny than a repeat aircraft. Builders are especially vulnerable to this type finding, they "know" they built it correctly so why would they need to scrutinize it?

Your life and those of your passengers depends on sound maintenance practices, make sure you give it the time and attention it deserves!

I wholeheartedly agree! Every other cond. insp. at least, I would have my good friend, (who holds an A&P with Inspection Authorization) follow up my Cond. Inspection. Sometimes he would find something that I had missed! Another set of eyeballs with no "no skin in the game" can save your bacon!

[jfogarty]

Just a few more observations. Walt you are holding the gascolator in question. What was used to plug the aft port? I can't understand why a builder would do the install this way, however, it has worked for a number of years. I would think the two outlets on the gascolator are to serve two engines and/or one could serve as a primer feed. Do most primer installations come off the top of the gascolator? I have the same gascolator without a primer.

Jim Fogarty
RV-9A Flying

[Walt]

Originally Posted by jfogarty

Just a few more observations. Walt you are holding the gascolator in question. What was used to plug the aft port? I can't understand why a builder would do the install this way, however, it has worked for a number of years. I would think the two outlets on the gascolator are to serve two engines and/or one could serve as a primer feed. Do most primer installations come off the top of the gascolator? I have the same gascolator without a primer.

Jim Fogarty
RV-9A Flying

The outlet ports, including the primer port, are both ported out from above the filter screen, the aft inlet ports fuel into the bowl and then fuel flows up thru the screen to the outlet ports. The way is was installed bypassed the screen totally, debris would just pass right through like a piece of tubing. That's why I found debris in the "last chance" carb inlet screen which is what tipped me off to the incorrectly installed gascolator (it was clean).

A hex pipe plug was stuffed in the inlet port and then ground smooth so it would fit flush on the firewall.

The dual outlets I suspect are there so the unit can be mounted on the left or right side of the firewall.