Van's Air Force
Western Canada Wing |
Regarding the breakage of my front gear leg, I have the following to offer the RV community.
As to why the front gear leg broke, Van has not released to me the full metallurgy report, and does not plan to in the future. He has written me indicating that my “gear leg showed signs of metal fatigue” and that it “had some surface imperfections which could have lowered its fatigue life.” He also indicated that my “new gear leg has been inspected and found to be free of surface imperfections,” and that “the service life of this gear leg should be much longer than the first leg...However, we don’t know exactly what this life might be.” He further indicated that, while the prototype RV-6A nose gear leg had been replaced “at about 1600-1700 hours of use, we did not inspect it for the surface conditions we are now aware of—this gear had been replaced for other reasons.” In closing, he stated, “...we are confident that the current production, inspected gear legs will offer a long service life under normal use.”
I have to say that I am very satisfied with Van’s organization for the service and cost breaks he has offered to me in getting N925RV back into the air. During the past eight weeks, Tom Green and I got to hear from each [other] often, both on the phone and by email. Tom expedited the repair and refitting of the new front gear leg to my motor mount, which greatly lessened the time back into the air. He and his office personnel are to be commended for their efforts.
However, I am a bit more critical of Mr. Van Grunsven’s decision to not share the metallurgy results with me. While his letter indicated that my gear leg “had some surface imperfections” that lead to “metal fatigue,” I am still at a loss as to what these “imperfections” were, and where they came from. Where they self induced during the kit assembly process? Or where they introduced in the gear leg manufacturing process? If it was self induced, how was that achieved (file marks?) and how might it be prevented next time (and with the next builder)? If it was a leg manufacturing process issue, are there any more out there that need to be found? (Even one should be too many if it’s “surface conditions we are now aware of.”) More importantly, if it is a manufacturing issue, why not communicate the findings to all builders as a warning so that possible problems might be found prior to another failure? (I guess that’s what I’m doing...)
In my opinion, all RV-6A aircraft gear legs, especially older gear legs (mine was purchased in 1991), should be inspected for this “surface condition” to ensure against future failures. We all should periodically inspect this leg, especially after the occurrence of any front wheel shimmy condition. If a crack is found early enough, you won’t be subjected to the repairs that I endured. My gear leg cracked in excess of 50% through the rod prior to breaking.