Private Pilot Resources - Aviation Blog

I obtained my private pilot license in 2006. This site is dedicated to capturing little gems of knowlege I collected during training. Periodically I add items I find during research so that others might benefit from them. Please review the disclaimer at the bottom of this page.

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Location: San Jose, CA, United States

In 1999 a friend invited me to go flying and I was hooked. I live in the Bay Area about an hour south of San Francisco and fly out of Reid Hillview (KRHV). Please do get in touch and lets go fly!!

Saturday, January 26, 2008

What does a stall & spin look like

I always wondered what the view out the window would look like in an inadvertent stall spin. After all, enter a stall during uncoordinated flight and you'll soon find out. The weather is crappy today so I'm doing a little armchair flying and ran across some great video clips on YouTube. Somehow it was important for me to actually see how fast the plane appears to point at the ground.

Cessna stall spin
...and another one
........and another one
...and just because it's so much fun

spinning in a Citabria
and spinning in a Decathlon
and in a Vans RV-12 where you can actually see the aileron inputs nicely. This one also has a great demonstration of airflow separation during the stall.

Stall horn testing - Preflight

Ok, so I finally got tired of not testing my stall horn during pre-flight. On tab-actuated stall horns such as the one I encountered when I was flying the Piper Archer it sure was an easy task. Turn on master, lift the tab, and hear the horn. Try being thorough though on a Cessna 172 and it's an entirely different story. Theoretically, you're supposed to suck on the opening of a dirty airplane with the wing a head or two higher than you. Sure, that's going to happen...NOT. So as a result it seems to be an accepted practice to just visually inspect the opening for any obstructions. After all, you're not going to fall out of the sky just because the stall horn doesn't work. Or will you. Last week we went out and practiced slow flight. Sure was easy with the stall horn buzzing. Oooops...what if it hadn't worked. It was at this point that it occurred to me that maybe I ought to find a way to check that stall horn on the next pre-flight. A few months earlier I had seen another pilot on my field pull out a strange little home made device. One of the instructors had created it for some of his students, so I decided to have a go at it. Quick run to the hardware store for some flexible plastic tubing (mine is a little too rigid, so select one that is flexible enough). I also picked up a little piece of thick and compact foam that's flexible enough to mold to a surface. I squeezed the tubing into the foam twisting it and cut out a nice little hole with the tubing. A little super glue to attach the foam to the tubing and about 90 cents later you have the perfect stall horn tester. Press the foam to the aircraft leading edge right over the stall horn opening and suck on the tube. Voila! Sure I could have picked up a little pump that the aviation catalogs are selling, but I'm certain those wear out eventually and I, like most pilots, just like things that can't break. No more excuses for not testing the stall horn.

Sunday, January 20, 2008

Preflighting a Cessna 172 revisited

I must have preflighted the 172 over a hundred times now. Every now and so often I take an hour with a CFI for some recurrent training and I usually ask to be observed as I step through my pre-flight. Over the years I've learned that every CFI contributes yet another piece of wisdom that lets me know and understand that machine, which is about to take me aloft, just a little better. Last year it was a mechanic that lubricated a flap push rod that explained how the left flap is tied to the right via cables. By pushing up on the left flap one can test for excessive play in that connection and at the same time observe whether the rollers are actually moving in the tracks. If they don't it leads to excessive wear. Thanks to that same mechanic I now also check for chafing on the top surface of the flaps.

Today's pre-flight was no exception. Tom pointed out three new items that were either new or just not clear to me before.

1) Ever wondered how many static wicks your airplane can be missing and still be flown safely? The Cessna 172 should have 8 of those wicks, 2 on each wing, 2 on the rudder and 2 on the stabilator. They are there to disperse static charge that builds up all around the aircraft and that could interfere with radios. It is safe to fly with a maximum of 3 missing.

2) Tom asked me to explain what I am looking for on the safety wire and what the safety wire is there for. With safety wires you are looking for broken wire, which would indicate that a stop screw has moved or a connection has come loose. On the tail of a 172 one would check for the safety wire to be intact on both sides of the rudder cable connection (that one I knew). You also check for safety wire to be unbroken for the 2 rudder stop screws and the elevator stop screw. A broken wire indicates that the screws have moved and that would allow the rudder or elevator excessive travel.

3) How would you know that the break hydraulic lines are leaking? My answer, look for break fluid next to the tire, missed the point. I had forgotten to set the plane's parking break. The way to get pressure on the hydraulic line so that fluid would be forced out would be to either apply the breaks or in this case just simply set the parking break and then look for leaking. A plane that has set there without a break applied might not show lots of leakage, especially in a training airplane that was just parked. Apparently the hydraulic lines like to fail in the corners where they are bent or where they are rubbing up against the landing gear. Especially when wheel pants are not attached these lines vibrate in the wind against the gear and start chafing over time.

4) I always visually inspect the openings in the plane's cowling to make sure no birds have started nesting. Especially in the fall when nests can appear from on day to the next. What never occurred to me is that the best place for a nest is in between the cylinders where a visual inspection won't find them. If the engine isn't hot, run your hand through that space to make sure no critter built a home there.

Sometimes it takes another pilot or CFI to ask provocative questions to make you think about what to check during pre-flight. Most importantly, always ask yourself "why am I checking this" and "what would this look like had it failed or become damaged".

Off it was to another fun flight. 7 rounds in the pattern. The ceiling lifted to 4000 feet and we headed South for slow flight and stall practice. In March I'm coming up on my first Bi-Annual Flight Review (BFR). I'll be going the Wings route, so look here soon for the next entry on completing the Basic Wings phase in lieu of a BFR.

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