RFSchaller
Well Known Member
Always thought ?certificated? referred to having a type certificate not airworthiness certificate, so I don?t see how EAB, ELSA or SLSA could be considered ?certificated?.
That would be a neat trick since the FAA would be basically arguing with the FAA.
https://www.faa.gov/aircraft/gen_av/light_sport/media/lsa_cert_8july2013.pdf
Always thought “certificated” referred to having a type certificate not airworthiness certificate, so I don’t see how EAB, ELSA or SLSA could be considered “certificated”.
All aircraft issued an airworthiness certificate are certificated, whether special or standard. ?Certified? is colloquially used to mean standard certification.
All of the people in the FAA, DAR's, etc., that I work with indicate that it is the exact opposite.
It is also maintained to a standard such that 100 hour mandatory inspections are required, instead of only Annual inspections, as required in the Experimental LSA aircraft.
An aircraft with a STANDARD category Certificate of Airworthiness (FAA 8130-7 Form) like the typical Cessna, Piper, etc.
I believe that a "Standard" Airworthiness Certificate is FAA form 8100-2.
I'm told this retrofit is required for my factory built Van's, just wonder if the homebuilt RV 12 owners are also forced to do this or have the option to assume they won't be putting the same stress on the part as a 1700 hour trainer.
if you already have a gear mounted i don't understand why you need the long drills at all. why can't you use the old gear as a mirror image against the new gear and match drill or use the old gear and match drill a template to put against the new gear?
Bob,
After your question on my post I went back and reread a lot of the thread to see if I had missed something. What I?m not clear on is did the failed gear leg failure initiate at the predicted point from the FEA? A slightly different location might mean there was some preexisting flaw.
...which under significantly high (but possible) loads on the leg can cause the material at the point of focused stress concentration to yield.
Greg, sorry to keep this going when you've already given such detailed answers, but knowing that the original gear leg was load tested, how much load or rather overload under impact is needed to cause the initial yielding? Given that there is a long wait now for delivery of upgraded legs, it would be useful to have some idea of what kind of impact is required to trigger the fatigue sequence.
I know the history of my plane and have at least an anecdotal idea of what sort of forces the gear may have been subjected to, but would like to get a better sense of how much risk I may be running by continuing to fly it. I suspect there are others who are probably wondering the same thing.
Scott
Can you please clarify time of compliance?
A RV 12 with 30 hours has his annual inspection due today and he cannot fly until the new landing is available and installed.
A RV 12 with 1400 hours has his annual inspection due January 2021, he can fly on his old gear until then.
I am waiting for a DAR inspection and I have no time on my old gear, can I fly for one year after my DAR inspection?
Thanks
Joe Rhodes
Thanks Scott
Yes, I am EAB however I will comply with all safety bulletins for the safety of my passengers and myself.
It would be foolish to ignore service bulletins by some sort of loophole.
My View
Joe Dallas
I can't help but feel like a shot messenger.....
I don't see that I implied that you could use a loop hole. S.B.'s are purposely issued applying to all aircraft certification levels and the hope is that all owners will follow them.
But as a company, Van's also assumes that customers are able to use logical reasoning in how a particular SB or revision might apply to them.
In a case such as yours, I think most people would assume that if an 800 Hr airplane were safe to fly for a year until the next condition inspection, that a brand new one with zero flight hours would be as well.
Having made that decision, a person would then be allowed the freedom to defer it for a year since the S.B. is not regulatory.
The original comment was based on the fact that if your airplane were an S-LSA, compliance is regulatory.
I have two questions…
The fairing on the nose gear strut is fastened with two #10 screws – could this also be source of stress concentration. I would imagine the long straight section of the nose strut flexes considerably with poor landing technique.
I was also concerned about drilling a hole for those screws. I think I'm going to use some double sided tape to capture the nose strut fairing in place.
If there was a concern about drilling holes in the gear leg for the leg fairing attach screws, they would have never been specified there originally, and/or they would have been deleted when the new nose gear leg was designed, so no FEA on the screw holes is like to happen (see below for reason).
Sorry if that sounds a bit sarcastic.... I don't mean it to be, but it is the reality.
A bit of engineering and physics needs to be applied to understand why these holes are not an issue.
One, would be to understand what the bending loads are along a beam or arm such as the nose gear leg. The bending loads are the highest at each end where the arm attaches to other members (think of the effect that a long lever arm can have to amplify force). The bending loads are the lowest at the very mid point of the arm (that is where the lever arm is the shortest distance to other members where the loads are being applied).
That is why the screw holes are at the very mid point of the leg, vs a pair of holes at the upper end, and a pair at the lower end.
Another factor is the way the loads are distributed through the arm.
In the case of the nose gear leg, when a high upward load (hard landing for example) is applied, and the leg tries to bend, the material along the very top of the tube is being compressed along the length of the leg, and the material along the bottom edge of the tube is being stretched as the tube tries to bend into a curved shape.
The screw holes are purposely located on the sides of the leg, which puts them in the neutral axis of the tube..... the portion of the tube where there is no compression or tension load when the leg is being loaded vertically.
This is an overly simplified explanation.
Go to this reference (or just google "neutral axis") for more details.
https://www.quora.com/What-is-the-neutral-axis-of-a-beam