Error Chain

First flight surprise! Theres a reason you should follow the plans when installing a canopy latch.

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I have flight-tested a few airplanes after annuals and rebuilds, but so far, I have only done two first flights. The first one was our RV-7. Apart from warm CHTs on a brand new motor, everything was as expected, and we easily progressed through the fly-off stage and enjoyment of the new plane.

The second first flight was another story.

Eighteen months ago, I was approached by a guy who was about to buy a new, unflown RV-12. He asked if I could do the initial flight and subsequent flight testing required by the English regulatory system. After establishing who had built the airplane and who had signed it off, I agreed to become involved.

The RV-12 in question had been built to a high standard, with a polished finish and was allegedly ready to go—apart from a couple of minor snags. Time to get curious, I thought. The airplane seemed to have been sold and delivered by road in a bit of a hurry; I think the new owner was naturally keen to get going and agreed with the builder to look at some of the minor jobs after taking delivery. I wanted to go through the airplane with the new owner’s inspector to ensure that these items weren’t an issue and would easily be solved.

As designed, the RV-12 latch handle can only be turned one direction, and will positively latch in the hook. If it is installed in reverse, it will still move correctly, but only the “nub” on the end will engage the latch hook.

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First was a lack of fuel pressure indication, and a similar snag on charging. Neither was a major issue and both were easily solved. But the fuel tank had not been calibrated. The owner said that it could be done later and we could fly it now by just putting in a known amount of fuel. Err, no, I thought—let’s go ahead and calibrate it now.

So, we started through the calibration process and almost immediately, we were awash with fuel. There was no gasket under the sender in the tank.

Oh Boy! Now I was beginning to reconsider my offer of help.

However, we sorted out the problem, and I had a long chat with the inspector, away from the owner. After again going through everything, we finally agreed that it was ready to test. The paperwork was done, the weather was fine, the GoPro attached, we were good to go.

In this view, the asymmetry of the latch is apparent—if installed 180 degrees out, only a small portion of the latch handle will engage the latch hook on the roll bar.

To say that Van’s designs and produces good products is an understatement; the RV-12 flew beautifully—a real sweet little airplane.

After around 15 minutes of gentle expansion of the parameters, I decided to take it up to a medium speed (nowhere near Vne) to check for straightness, vibrations, etc.

At that point, the canopy came open!

It does concentrate the mind as you are short of two hands—one to grab the handle, one to grab the papers, one to hold the stick and the fourth one to control the cursed Rotax sprung throttle.

Anyhow, I ended up with one hand on the canopy handle and one on the stick, with the throttle closed and locked. Hmm…OK, we are safe—however, we are gliding and the canopy does float a long way up. Attempts to get it closed and locked proved futile—time to keep flying the airplane and figure out the problem on the ground. (If you have ever seen the balloon dance with the naked chaps swapping balloons, that is how I was until I could come up with a system of quickly swapping hands to attend to all needs.)

In the author’s RV-7, the latch handle is almost symmetrical on either side of the shaft, so it will latch in either direction (although one direction is more secure). In the RV-7, there are additional latches on the sides if the roll bar latch isn’t closed.

I was soon on final, the landing was fine, the heart rate reduced, and I taxied in.

The big question, of course, was why the canopy popped open, and why it wouldn’t re-latch in flight. On further questioning, the new owner said, “Oh, yes I swapped the handle around because it was stiff.”

Of all the small things that you would have taken for granted, it was one of these that bit my tail: On inspection, the overlap when 180 degrees out was adequate on the ground, but insufficient when flight loads pulled the canopy up. To say he was a little sheepish was an understatement.

Anyhow, the rest of the testing went fine, and he is now happily flying a super nice RV12 around the skies of England.

Sometimes, it is the startlingly unobvious things that can contrive to create a problem. Many an airplane has been lost on a first (or second, or third) flight because the pilot was startled by a minor issue that really didn’t affect the ability to stay aloft. In the end, the old saying, “Fly the plane,” is always the best thing to remember—and always the best policy.

Photos: Marc Cook, Joe Blank and courtesy Van’s Aircraft

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