Flying Friday: of shops and annuals

I haven’t been flying much lately, sad to say. This is mostly because of weather, but partly because I have been busy with other things. However, as spring approaches, I’ve been eager to get back in the air. A couple of weeks ago, I went flying with John, my CFII, and shot some practice instrument approaches. While I was a bit rusty, I was still able to fly a good ILS, even in the winds, but I had a little bit of trouble making the KLN94 do what I wanted to get set up for the GPS approach into Huntsville… its time is coming, though, and I hope to finally get the Avidyne IFD540 installed in early summer. That’s still some time away, though. There are two hurdles to cross first: getting our engine monitor installed and getting the plane through its required annual inspection.

First, the engine monitor. Like almost all other airplanes of this vintage, 706 has a battery of analog gauges that report on the engine health. There’s nothing wrong with this, as these instruments tend to be very reliable. The tachometer, manifold pressure gauge, and fuel flow gauge are all very important. However, the standard engine instruments have several shortcomings. First, our plane had a conventional single gauge for reporting exhaust gas temperature (EGT), and the aftermarket cylinder head temperature (CHT) gauge wasn’t working. The problem with single-channel EGT and CHT instruments is that they only tell you what one cylinder is doing, so there’s no way to see what’s going on with the other five cylinders. Second is that the gauges are scattered all around the panel; besides the EGT and CHT indicators, there’s a suction gauge (which tells you whether the engine-driven vacuum pump that drives the gyros is working), the fuel gauges, and so on. Third is that these gauges only show instantaneous data, not trends, and they don’t alert you to unusual conditions.

The solution: get an engine monitor. After much shopping and head-scratching, we settled on the CGR-30P from Electronics International. The video below will give you an idea of what this magic box does:

From my perspective, the CGR-30P does two critical things: it alerts you when an engine parameter goes out of limits (say, if the oil pressure decreases unexpectedly), and it logs data that can be used for later analysis. As a nice side benefit, it monitors CHT and EGT for all six cylinders, which has the dual benefit of giving early indication of potential misbehavior and providing the data we need to operate the engine as efficiently as possible.

(Brief digression: there is a lot of religious argument over the “correct” way to adjust the fuel/air mixture in piston engines. This article by noted mechanic Mike Busch explains the topic, and the debate, very well, along with recommending the approach that I will be using once I have accurate CHT and EGT data).

Getting the CGR-30P installed, though, requires an avionics shop. Derek and I have struggled with finding a good local shop. There’s no avionics shop at our home field, and C-Cubed, which used to be at Huntsville,  closed a few months ago. Their spot was taken over by a company called Advanced Technical Avionics (ATA). After a brief period of confusion occasioned by a management change (translation: someone got fired), we got the plane into the shop on Tuesday to start the installation. With any luck, in a week or so, the plane will be back in the air– which is good, as I have a trip planned to New Orleans next month for the New Orleans Sprint triathlon, my first of the year.

Right after I get back from New Orleans, the plane needs to go in for its annual inspection. Every general aviation aircraft is required to undergo a comprehensive airworthiness inspection each year. There are specific things that the shop will check based on the engine and airframe manufacturer’s recommendations, and there can be other things that need checking or adjustment based on how much the plane has been flown. For example, some components need to be checked every 100 or 500 hours. (This example inspection checklist gives you an idea of some of the things that must be inspected.) Then, because this is a 40-year-old airplane, there will inevitably be some things that need to be repaired or replaced because they’re worn out or broken. For example, our air conditioner doesn’t work any longer, so we’ll have the shop take a look at it as long as they’re crawling around inside the plane.

On the advice of Savvy, our maintenance management company, we’re using a Piper service center for the annual– DLK Aviation in Kennesaw, Georgia. That means that we’ll have to ferry the plane there and back again; I’ll probably rent a plane from Redstone and pick Derek up after he drops the plane off, but driving isn’t out of the question. Once the plane arrives, after one to two weeks (and some unknown amount of money, depending on whether there are any expensive surprises), we’ll have the plane back and be good for another year.

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