Preparations to Leave

So yesterday James (my Aircraft Mechanic friend) and I finished off the Twin Comanche's annual. There were surprisingly few snags, and the one big snag I was expecting turned out to be not so big after all, which is always a pleasant surprise.

The left auxiliary fuel tank was leaking, and I suspected it to be the rubber fuel bladder itself that maybe dried out and cracked, so we started by opening up the top wing panel to inspect the rubber bladder. After inspection however the evidence seemed to point to a leak somewhere from the center of the plane, under the cabin floor, which is where the fuel selectors (to select which fuel tanks to feed from), and the gascolator system is located. A gascolator is a device that extracts water from the fuel system to prevent it from getting into the engine, which could cause an engine failure. It sounds pretty fancy, but in keeping with most aviation technology its actually quite simple. Water is heavier then fuel, so if you mix the two together you'll find the water at the bottom. The gascolator is simply a small bowl at a low point in the fuel system. The fuel line comes in near the top of the bowl, and then leaves near the top. The bowl stays full of fuel, and any water that gets into the system flows through the bowl and then sinks to the bottom, where it can be manually drained.

I didn't fly the Comanche much during the winter, and at some point water accumulated in one of the fuel lines going into the gascolator, and froze, which split it open, and caused the leak. Replacing a fuel line is much easier and cheaper then replacing a rubber fuel bladder, so I was happy.

Another thing was that the landing gear bungies were due to be changed (every 3 yrs or 500 hrs), so we had to change those. These are just bungy cords, about 3/4" in diameter that are rigged to assist the landing gear in coming down and staying down and locked, especially in the event that the pilot has to manually extend the landing gear if he has landing gear problems. Once again a fine example of aviation technology. You can just imagine the engineers discussing that one when designing the airplane:

Lead Engineer: Okay guys, we need to come up with a way to make it easier for the landing gear to come down.

Engineer #2: Rubber bands. Hundreds of them stretched around linkage in the wing to pull the gear down. Simple and effective.

Lead Engineer: Perfect, I'll head down to Business Depot and grab a bag.

So we changed the bungies, completed a bunch of gear swings to make sure it all worked properly, and that was that. Despite all the simple technology in airplanes, it still amazes me how many moving parts, mechanizms, and systems there are in an airplane. While I don't necessarily consider turning wrenches a great way to spend a weekend, its pretty cool to open up and dig into the guts of my airplane every once in a while. Its fascinating to think about how much stuff is going on mechanically when I'm in the cockpit pressing buttons and throwing switches as we're hurtling through the sky. Its really quite impressive how reliable these machines are, taking that into account.

I didn't get a chance to take it on a test flight today since the weather was no good, hopefully tomorrow I can take it for a lap and check everything out ok before I head out over the Ontario wilderness. I finally got the call from my employers, and I'm to head up on Thursday, weather permitting. Stay tuned.

I've also been purchasing some small toys under the guise of "survival gear". I bought a magnesium firestarter, a small handheld compass, a stainless steel waterbottle (for everyday use but the steel also means I can use it to boil water in a survival situation), and this styling mosquito jacket. The jacket is basically a pull over jacket made out of mesh material to prevent insects from getting near my skin and biting. It has a hood/mask that completely encloses my face with a little zipper at the neck to flip it off if I don't want my face enclosed. Its stylin.

So I'm pretty well ready to go, just waiting until the appointed time.