Bits and Pieces
Upon Further Consideration!
By Ian Brown, Editor – Bits and Pieces, EAA 657159
I promised a bit more on my accident last month. I'd like to focus on two simple ideas: how it happened and how I could have avoided it. Both should present valuable opportunities for learning, especially but not limited to builders of RV-xA series of amateur-built aircraft. But first, I'd like to thank Keith Walker for pointing me toward this interview with John King (yes, of John and Martha fame).
King stresses, "Flying is dangerous, and we do ourselves a disservice by claiming anything else." It's the fact that pilots as a breed are very careful and methodical, and that they take the danger seriously, that makes the accident rates a lot better than they would be.
How my RV-9A flipped over
Since the Stanstead-Weller Airport (CTQ2) grass strip was new to me and the approach was over trees from the south, I didn't actually touch down until halfway down the 2,600-foot runway. One thousand, three hundred feet equals 433 yards - not a lot of runway left! I flipped more than eight seconds after the wheels touched down. I was seeing about 200 yards of runway left, and decided to apply some braking. It was then that the trouble started. The nose wheel started bouncing with the extra pressure. And perhaps I didn't have enough back pressure on the stick, but I don't remember. After about 40 yards of bouncing, the propeller finally made contact with the ground, and the plane quickly flipped tail over nose. For those of you who are unaware of the debate about the Van's tricycle gear series nose wheel design, there are some interesting discussions here and here. If you would like to see an example of how it looks to flip an RV over, you need go no further than YouTube.
You should draw your own conclusions, but when I look at my nose wheel the bearings are certainly quite tight despite my best efforts to tighten them correctly during the annual. So my conclusion is that I should find a better nose wheel bearing. There are at least two optional bearing changes - Matco and AntiSplatAero. Both attempt to fix the tendency for the gear leg to begin to bounce up and down as shown in this video made by an EAA member in Chapter 538, based in Phoenix, Arizona. Download video
There is a bit of confusion around the description of this as a shimmy and the attempt to limit it with the damping nut and compression washers. I think that adjustment does a fine job of limiting sideways movement of the castering nose wheel, but I can see no connection with that adjustment and the likelihood of vertical bouncing or bending.
Avoiding this kind of accident
This might seem too easy to say, but the Word of the Month should give you a clue. You don't have to land most of the time, unless you're flying a glider or if your aircraft has become one. It's a bit more complicated than just never having "been there, done that," though. There are stages to it, and the first one begins with the annual inspection. If I'd been reading more on the bulletin boards about known problems, I might have picked up on the importance of making sure that the nose wheel is very free to rotate with this kind of gear leg. That's difficult to estimate with new grease on the bearings, so my choice would be for a new bearing design like the AntiSplatAero offering, which uses a sealed-for-life truck wheel bearing.
The next item is the whole aspect of doing your homework when landing on a strange field. I'd called the owner, George Weller, and he told me of his preference for landing from the south because it's uphill and avoids a rise right at the approach from the north. The winds were very light when we overflew the airport, which we actually did several times to figure out the circuit. It turns out that the approach from the south is also over trees. And the first section has trees on both sides, so it's a bit intimidating. You can actually learn a lot on the Internet these days by checking out a runway on Google Earth, as well as having read and digested everything there is to say in the CFS.
Having made this approach, we had a window of literally seconds after clearing the trees when I should have decided to overshoot, or as our American friends would say, "go around". That was perhaps my biggest decision-making error. No amount of aircraft redesign could change that, but perhaps the incidence of aircraft flip-overs could be reduced with the various nose gear mods suggested by either AntiSplatAero or Matco. Overall, there are other risks of not having a nose wheel, and without getting into that debate, I believe Van's idea was to produce a "safer cross-country plane" by originally making only the "A" version of the RV-9. Landing on grass may have been one of the reasons to open up to the design to a tailwheel configuration.
Lastly, having failed to decide to overshoot I should have kept full back pressure on the stick until I absolutely had no choice but to apply some brakes. In retrospect, an RV-9A should be able to land and slow to a crawl in 500 feet. As I saw the end of the runway approaching, I may have erred on the side of trying to control the slowdown like a car, rather than allowing the plane to slow down like a boat.
As I write this we have a glorious late-October flying day, and I'm jealous of all of you who have the option of going out and not landing, but overshooting or going around again. After all, not landing means that you can have a little bit more fun flying.
As for my aircraft, the good news is that the rebuilt, tested engine is back in my garage ready for the rest of the rebuild to be complete. I will buy a new engine mount, and completed empennage which I have already sourced, so the focus of the rebuild will be on the damaged areas of the fuselage and canopy.
To summarize, overshoot if you're not absolutely certain that you have a perfect landing, apply lots of stick/yoke back pressure after wheels down, and stay off the brakes until you're at walking speed. Let me know what you think about these ideas. They're just one point of view, and we would like to hear yours.
Upon further consideration, I should have probably just enjoyed the overflying of this airport and then just turned around and gone home. Even on very short grass, an unmodified tricycle RV nose gear will demand a very good pilot to land and keep the nose wheel pant in one piece, not to mention the rest of the aircraft!
As a final note, on behalf of all our readers I would like to welcome our newly elected chairman, Jack Pelton, who is also acting in the role of president while a replacement for Rod Hightower is sought. Canadian members look forward to interesting changes to come.