Wednesday, August 15, 2012

This is why we can't have nice things...

Perhaps I shouldn't leave Silke topless when I'm working in the hangar; those birds are not very friendly.

This is really more of a composite posting, which means it's comprised of three work sessions but will be written as if it all happened at once. A 'composite' posting would also be known as a "lie" if this blog was an autobiography, but I have it on good authority that I can dodge the accusation of lying simply by calling it a memoir. So there you go.

Nearly done with the TSA phase, all that was left to do was to remove and discard the old center panel. It will no longer be needed because the new avionics suite no longer includes the separate Garmin GPS for which a large hole had been provided in the old panel. The removal of the old panel should have been easy, but naturally it wasn't. It's normally super simple to drill out blind rivets (they never see me coming...) but the little copper colored rivets aren't so easy. The problem is that they don't allow themselves to be drilled out. Rather, they just spin in the hole. I tried grabbing them with a pair of pliers to hold them in place, but that just caused an even bigger mess.

I finally gave up on any kind of subtle approach and went at them with the Dremel.

Finally! Into the scrap box.

I was then instructed to pull the pitot line back out of the avionics bay and all of the bulkhead bushings, all the way back to the fuel pump. Basically, the directive was to remove the pitot line. That didn't seem right to me. After all, while the new computer unit gets installed in the tail, the pitot tube is still up at the front of the plane. A pitot line is still going to be needed to carry data (in the form of pressurized air) back to the computer. Why in the world would I remove a line that's already in place, especially when I know how hard it was to get it in there in the first place??

I looked ahead a couple of pages, and sure enough, there it is: the pitot line is back!

I called Kyle, Aviation Coordinator for The Jackson Two, to find out what was going on. He said that they wanted the pitot line removed to make it easier to pull some new wires through the bulkheads. He also said that Van's has us simply abandon a set of now obsolete wires in place. Kyle suggested that the removal of those wires would provide space for the replacement wires and that it would be perfectly acceptable, and perhaps even desirable, to leave the pitot line in place. As you can see above, I modified the directions accordingly.

That was the end of the TSA phase. It transitioned immediately into the modification phase. The first step was the installation of a row of nutplates. I'm not sure what they will be used for, but I hope it is to provide a rivet-less installation for the new center panel.

The old avionics system (the Dynon D-180) was mostly one big, deep box that mounted in the panel. It had all of the various components, absent the magnetic compass sensor, included in that one box. The Skyview is different. The screen itself is very thin because it is essentially just a display. The "smarts" of the system are now provided in separate boxes. This allows for expandability as new features are added, and it allows for easier maintenance. All of those modular components have to be mounted somewhere, though, so new holes have to be drilled to provide mounting points. Rather than have us try to precisely measure where the holes should go, Van's provides clever little drill templates. Each temple provides the drill locations for multiple components, so a little caution is required to make sure you're drilling the right hole in the right place at the right time. Two holes are provided to cleco the template in place.

One of the more hated features of the D-180 installation was that the connector used to attach the D-180 to a computer in order to upload software updates was located in a somewhat inconvenient location. The location to be used for the Skyview is just under the avionics shelf. Also, rather than the old-style serial connector that required a USB adapter in order to attach to any 21st century computer, the new connector is itself a USB plug. To make the opening for the connector, a series of holes are drilled.

Then side cutters are used to finish the opening.

Another new module to be installed is one designed and built by Van's. Essentially its just a big junction box where all of the various inputs and outputs from the computers and sensors meet and get shuffled off to their destinations. I call it the O'Hare box. Anyone that has done even a small amount of air travel will understand. This box must also have some electronics in it that will be generating heat because new cooling holes need to be drilled for it.

The next few holes get drilled into the firewall. This is always a treat - drilling through stainless steel is nowhere near as easy as drilling though aluminum.

I had to put a block of wood on the other side of the firewall so I would have something to push against.

There were a few more holes to drill, but as I was getting ready to do so I heard the unmistakable sound of maniacal bird laughter out in front of the hangar....

1 comment:

Anonymous said...

You will find this thread useful in the tasks of installing the new adapter harnesses. Save that old center panel, you might want to go ahead and install this modification - it should be no issue at inspection - Bill H.

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