I?ve been thinking about this particular incident over the last couple of days and thought I?d put out a few ideas for comment. I have had access to two RVs that were damaged in the landing gear area, an RV8 and an RV12. My RV8 hit a car on takeoff and effectively removed the gear legs from the aircraft, a few years back, and I just finished rebuilding an RV12 that was substantially damaged in a hard landing. Both landing gear are very similar, in that they are flat metal legs held to the plane with three bolts and a saddle assembly. My observations are:
-The bolts that attach the gear are very strong and in the case of the RV8, the bolt heads actually broke off rather than bend the bolt or the nuts pulled right off of the threads. There was very little bending involved.
-On the RV12, all bolts and gear legs were intact with no damage. The center section was twisted some in a couple of spots, but that?s all.
-The fuselage skin and ribs on the RV12 seems to be the weakest part of the structure in that area. On the damaged RV12, the center section rotated about 30 degrees and the fuselage structure gave way. There?s no comparison between the thick center section and the surrounding structure behind it.
-The damaged RV12 landing gear was still firmly attached to the center section and I was able to remove the nuts and bolts to separate the center section and gear legs.
So, what could have caused the wrinkle behind the gear and to the brake line? My guess is, since the rear fuselage cone and tail assembly is on a rather long arm behind the gear, it creates a lot of momentum if you are on a steep approach. Abruptly pulling up on the runway and actually touching down likely caused the rear fuselage to deflect downward, causing the wrinkles and contacting the brake line. Adding a lot of braking power just at or after that instant probably added to the overall force on that area where the fuselage joins the center section. (Strictly my opinion.)
At a minimum, I would recommend that the owner remove the center inspection panel in the baggage compartment and inspect the baggage compartment ribs for compression where they attach to the center channel. You may also be able to inspect through the access panels under the plane. In the damaged RV12, all of these ribs were damaged, obviously much worse than this one would be. There could possibly be some wrinkling of the bottom fuselage skins as well. I suppose that the side skins could deflect downward without doing other damage, but I'd check anyway. I would be interested to hear what the final decision is as to what happened and why.
I doubt that the gear legs actually moved aft enough to touch the fuselage skin, even if the bolts were loose. If they did, there would be evidence of it on the channel and the bolts themselves. There would be marks likely on the channel and the bolts would be bent. They would have to have been really loose!
Having flown the RV12 for several hours, I noticed how light the plane really is. There is no comparison to a Cessna 150. The RV12 is not a trainer, it is a sport ELSA. In my opinion, it was not built to be a trainer but was purposefully built to be light, agile, fairly powerful for its size and specifically an LSA for sport type flying. Although it will likely stand up to typical use, I don?t think it will stand up to a lot of rough use without some type of damage, like we are seeing here. Additionally, the change to a different engine, in some cases where they are built as EAB planes, can contribute to this problem since it is probably added weight and power, which puts additional stress on the airframe. (Again, strictly my opinion.)
Personally, I really like the RV12 and I think it is a wonderful flying airplane if flown within the envelope for which it was designed. In fact, I find myself flying it more than my RV8 since it is that much fun, so I hope we can find out what really happened here.
The above are only my personal observations set out for your review and I hope they help.