Find us on Google+ Inventor Tales

Friday, January 22, 2016

5 Lessons Aircraft Maintenance Class Taught Me About Life

Last week, I finished up yet another class in aircraft maintenance at Mount San Antonio College.  This course was "Materials and Science", and involved learning all manner of aircraft hardware, as well as material properties, and non destructive testing.

A photo posted by Jonathan Landeros (@jlanderos1973) on


Between my time of learning to identify different types of corrosion, tapping threads, and test material hardness, I had a chance to observe my fellow students, as well as reflect on how I approached and learned.  I also came to realize that my learning went beyond the syllabus of the class.

So here, in 5 bullet points, are what Aircraft Maintenance Taught Me About Life

1) Don't Forget the Details!

One of my lab exercises was making a semi rigid tube.  That meant sizing, bending, flaring, and assembling the fittings together.  The instructor made a point to say that the tubes are critical for the flares to ensuring a pressure tight seal.


I followed each of the steps carefully.  My flares were the right size, the bends were spot on.  I was feeling confident!  So with my chest puffed out in pride, I plugged it into the test rig and waited for the instructor to be impressed and proclaim me a prodigy.

The instructor pressurized it to 1000 psi, our test pressure.  He sprayed a soapy water solution to look for the dreaded bubbles that indicated a leak....  And.... bubbles....

Not a lot, but a slow and steady stream was parading out of the fitting.

The instructor pulled my tubing out of the test rig and looked into the flares.  "You need to clean those up.  I can see tool marks."  He instructed.  His experienced eye saw where the flaring tool had marked the inside of the flare.  Barely noticeable, they were causing the minor, but unacceptable leaks in my line.

So I sat the tool bench with fine grit sandpaper for 20 minutes.  I sanded until my fingers were sore, and the tips of my fingers numb.  With much less bravado, I approached the instructor and tested the tube again.

This time it passed, successfully holding 1000 psi with out a single leak!

Lesson?  Pay attention to the small, sometimes unseen details.  They can save the day when the pressure is on.

2) Don't Confuse Speed with Purpose.

There were definitely two camps in class.  There were the "fast movers", and the "slow movers".  The fast movers jumped into the projects, got their hands dirty, and got to work.

The slow movers, were a bit more cautions.  They read manuals, had discussions among themselves, and then picked up their tools.

Naturally, the "fast movers" had their projects submitted first.  But then, something interesting happened.

The "fast movers" ran into issues.  Hose fittings were over-torqued, dimensions were out of tolerance. Their progress was halted by the snapping sound of a tap breaking.

The fast movers began the process of reworking.

The "slow movers" on the other hand, while not perfect, ran into fewer mistakes, and were reworking their projects less.   Eventually, just like in the fable of the tortoise and the hare, the slower group had passed the faster group.  Their diligence meant they made steady, consistent progress.

A photo posted by Jonathan Landeros (@jlanderos1973) on



Lesson?  Don't confuse activity with progress.

3) Good Students Memorize. Great Students Comprehend.

Our written tests were multiple choice, and the questions, which are defined by the FAA, are pretty standardized.  That translated into a lot of going over questions, making sure you knew all the answers.

This was another place that the class divided into two camps.

One camp would drill on the questions, they could ask a question, and another student could answer with "B", and repeat the answer word for word from the test guide.

The other camp, would study at home individually, then just before the test, review the questions, talk about the answer, and then talk about why a given answer was the correct one.

Come test time, the second group consistently scored higher.

Why?

The instructor, knowing the answers are standardized, change the wording of the question.  In turn, that could change the answer.  That drilled in and memorized answer, "B", suddenly became "A".

A photo posted by Jonathan Landeros (@jlanderos1973) on



Many of the students that didn't understand the concepts and memorized the answer missed these questions.

The students who comprehended the concepts, could read the question, understand what was being asked, and could reason the correct answer based on the question that had been asked.

Lesson?  Make sure you understand the fundamental concepts behind what you're doing.

4) Not Only Have a Plan, Have a Flexible Plan.

Our class had access to two mills for machining parts, and three drill presses.  The mills, being more precise, were coveted machines.

Naturally, students who needed them would jump on them right away, stake their claim and work on their projects for as long as they could.

That left other students out in the cold.

Clever students quickly learned that the mills would often open up near the end of class, when "there wasn't any time to complete a project".

But the clever students would start their projects during that time, and use the mill to size their project, or center drill holes that would later be drilled and tapped.

This meant when they walked into class the next day, if the mill wasn't available, they would use the drill presses to complete their work, using the previous nights precision work as guide.

A photo posted by Jonathan Landeros (@jlanderos1973) on



As a result, they were still able to make steady progress through their project, while other students were still waiting impatiently for the mill.

Lesson? Have a plan, but be willing to adjust the plan to keep your goals on track.

5)  Lessons Come from Many Places.

My instructor was fantastic.  He had over twenty years of experience, he could relate his real, practical experiences to our class, making the lessons more meaningful.  But he wasn't the only one who was teaching.

My fellow students came from all walks of life.  I was one of two with engineering degrees.  There were recent high school graduates, a machinist making a career change, and a retiree learning skills to maintain his own plane.

We were wonderfully eclectic!

Those with passion showed through.  We learned from each other.

Students who had previous experience with machining helped those who had never tapped a hole.  I learned how to hand form chromoly steel from a fellow student who'd done it before working on previous projects.

When the instructor wasn't available, the clever students found another way.  Usually by learning from each other.

Lesson?  Great Mentors are all Around You.  Find Them

To end this post, I had a great time in class.  I learned a lot about aircraft grade fasteners, fittings, materials, corrosion, and testing.

But it was also an amazing lesson in life.  Making friends, working with them, and learning them, and having an opportunity to share a few lessons myself.

Most of all, I saw what my fellow students did to be successful, and I was reminded that success is not one great act, but a series of small acts repeated every day.  It's trying, it's failing, and it's dusting yourself off and having the courage to try again.

Now if you excuse me, I have a few lessons to commit to heart, and maybe think of what my next class will be.

A photo posted by Jonathan Landeros (@jlanderos1973) on






Sunday, January 10, 2016

Class Time Again - Materials and Processes. And Lessons for 2016

Here's the first post of 2016, and it's already been a busy year!  

I've started with another class in aircraft maintenance.  This time, materials and processes.  

That means three straight weeks spending evenings learning about aircraft fluid lines, hardware, and heat treating.  

It's a lot of work, but it's also fascinating.  At least for me! 

So my first week there I spent learning about all manner of fluid lines, I learned about semi-flexible lines, flexible lines, as well as the fittings that accompany them.  

The hydraulics in a speed brake in an F-86 Saber
(Taken at Planes of Fame Air Museum)


Just as important, was a lengthy lecture on how to install hoses properly to ensure they're effective and safe use!  

Examples of the right and wrong way to install a hose.
In short, don't twist the hose! (From AC43.13)


Like I said, it's fascinating for me. 

But there are plenty of others out there, who may not give one rip about the differences in flares in an automotive versus an aircraft semi-rigid line.  So what is the broader lesson to consider? 

The tools to design is becoming more pervasive as technology allows design tools to the masses.  Tools like Fusion 360 and Onshape have made 3D CAD available to people who only a few short years ago would have only dreamed of having access to that kind of design capability.

It opens up an entirely new world of potential of how people create things and build. 

But I think that raises a new challenge.  How do we design?  We now have amazing tools for creating and making things.  But that doesn't mean that we have the experience to use them to their full potential.

Those lessons can always be learned, but I don't think they should be learned in a vacuum.  "Someone always knows more than you do."  I'm told.

Mentor's come in many forms.  I encourage you to find yours!
Sure, you can create a 3D model, we can even run an Finite Element Analysis (FEA) simulation and see how the stresses interact on our part. 

But that doesn't help us know how to load a part.  We can't always know that a hose should have 5-8% added to it's length to account for expansion and flex.  Even today, software may not tell us that.  Experience does.

There's no account for experience.  Take this from a guy who has learned volumes from mechanics who have been doing their job for longer than I've been walking this planet.

You just can't beat that real world experience in my mind!

I can (and have) learned many a lesson from mechanics like the
those repairing this F-86 Saber!
So what do I think the challenge as we take our first steps into 2016?   

The "Internet of Things" rides on the backbone of the 'Information Superhighway".  

We're fortunate enough to not only have the tools to design, but access to volumes of information on how to design.  

Just look at resources like GrabCAD, and EngineersEdge.  There are so many out there!  

So as we begin 2016, let's design!  Find a mentor, find a class.  Let's embrace learning, and embrace our passions, whatever they are!

There is so much we can learn! 

Additional Photo Credits

photo credit: FDR 1978 Graphic Arts Shop Class - Mr Gruber - 04 via photopin (license)

Sunday, December 13, 2015

Text Masking - Making Leaders Disappear Since 2000.

This week's post is short and sweet, due to a little craziness during the week, but I still hope you all find it enjoyable and helpful!

The simplest things can drive you crazy,  One I encountered in Autodesk Inventor was a leader that seemed to randomly disappear.  It would just stop in one place, and start in another.

There seemed to be absolutely no good reason for it.

Why is this leader cut off?
It can be really puzzling.  The first time I encountered it, it completely threw me off.  It took a little bit of clicking and dragging before it finally dawned on me.

If you study the image above, you can actually see it, if you know what to look for.

The text box covered up the leader for the balloon.  Because of that, the masking "erases" the leader.  Dragging the leader out of the box, or dragging the box away from the leader, cause the leader to reappear.

And the truth of the fact was I had been a little careless and "whipped" the text box and made it far larger than it needed to be.

Here, I've shrunk the box to give the leader room.

It's so simple, yet at the same time, it can be so frustrating.  But in the end, it's really simple to fix.

So what's my suggestion?

Keep your eyes open, of course!  But also be aware that dragging a huge text box, because "it doesn't make that big a difference" can be asking for trouble.

Why?  It can cause a huge difference!  But just be aware, and know what to look for, and a big frustration can be reduced to just an "oops".

Sunday, December 06, 2015

Why is Inventor Constantly Freezing?!? - Wait, it's not Inventor's Fault!

Earlier, this month, I relived. something many CAD users have experienced.

Frequent freezing and crashing!  The bane of any CAD jockey!

When a CAD system crashes, this is what designing feels like.
Let's paint a picture!

A natural first reaction is to blame the CAD system, then perhaps the hardware.  Next may come the universe and any crimes you may have committed in a past life that have resulted in such Karmic retribution.

But there was one thing that blew everyone of those theories out of the water.  Well, except for the Karmic retribution theory.

Inventor hadn't been having this problems before.  It had been rock solid in the days, even hours.

So I traced back to what I was doing when the freezing and crashing started.  What had I done?

It turned out, I had imported a step file that represented a gearbox. A coworker confirmed that he'd experienced the same thing on his system with that same model.

Smoking gun located!

This was my culprit.  You evil, evil model. 


Confirming the Symptoms

Opening and inspecting the gearbox by itself, There were a few symptoms the model exhibited that indicated it as our sick file.  One of them may not be a problem, but together, things start to click.

1) The size was larger than I expected.  It was about 5MB.
2) The file took forever to perform even simple operations.  Things like placing constraints in an assembly, or creating a sketch in a part took several minutes to calculate.
3) Then aforementioned locking up and crashing.

At this point, I was sure I had found my culprit.

The Solution

I recalled a discussion with a colleague many years ago, I remembered a corrupt step file that had caused crashing in her system.

In that case, there was a weird, intersecting face that crashed the system.  The solution there had been to locate it and cut it away.

I actually tried that, but after about an hour, I hadn't located the problem.  I even tried loading the file into Fusion 360, and still ran into performance issues.

It was time for a different approach, which I should have tried in the first place, in retrospect.

I downloaded a new model!  But instead of a STEP file, I tried an SAT file.

And that worked!  The system was stable again.  It didn't crash again after that.  The file was less than 1.5 MB,

It feels good to be under way again!


The Conclusions

Bad or corrupt neutral files exist.  They're unavoidable.  Like a game of telephone, they can be caused by bad translation, bad imports, or sometimes, just bad luck. I couldn't tell you the cause of this models issue, and ultimately,, my superiors didn't care.

They wanted the project moving, they didn't care about which corner of the model had an issue.

I encourage you to be aware that "bad models exist!"

Some CAD models just fall in with the wrong crowd....


Moreover, when your program of choice begins crashing, remember that crashes aren't always the fault of the program.  Whether your using Inventor, Solidworks, Solidedge, or "My-CAD-Program-is the-best-and-if-you-disagree-your-wrong" CAD (We all know who those guys are!), look at what you did just before the crashing started.

It's always possible that whatever that was, a model, a bad constraint, sketch, whatever, is your "bad seed"

Keep your eyes open!




Photo Credits

photo credit: image29991 via photopin (license)

photo credit: L'hydrofoil via photopin (license)

photo credit: 45/52 Cat Burglar via photopin (license)