Yesterday I finished up the firewall forward part of the Valkyrie's yearly Condition Inspection, and today was the day to finish the airframe. Even though it's not due for sign off until the end of the month, coming off last week's long trip, and preparing for next weekend's LOE, I decided that going over everything was a good idea anyway, and I might as well use the checklist and sign it off if appropriate.
The results? The Valkyrie was almost perfect! All the pieces are still there, no cracks on any of the control surfaces (a great way to inspect rivets so to get out your bottle of Wash-Wax-All and clean the whole plane. Takes an hour, and you touch all of the exterior surfaces. Everything works, everything got lubed, and she's ready to go.
But I said "almost" perfect, didn't I? Well, there was one fiber lock nut on a 3/16" bolt that had loosened up, if you can believe that. The fiber was completely disengaged, and the nut was spinable by hand. The only REAL problem with this is that it is on the bolt at the bottom of the pilot's stick that holds the elevator pushrod to the stick.....
Now I am SURE that nut was secured during my airworthiness inspection - four people had gone over the control system before the DAR,and my DAR was particularly thorough. Had I removed the stick since then? I can't remember doing that, and even when I do, I usually pull the pivot bolt and lay the stick down, still attached to the elevator pushrod. I distinctly remember working around the stick when I checked the torque on the landing gear bolts. As I found it today, there was no washer under the nut, and all I can think of is that the nut was grabbing on the control column surface, and slowly turning on the bolt. Hard to believe, but I guess I'll never know for sure.
Of course, I have now checked every single fiber locknut in the control system, by eye and with a torque wrench. The bottom line - that is why we do Condition Inspections! You only see this bolt if you dive head-first into the cockpit, and if you have a boot on (I don't), you won't see it even then. But you can reach down and feel it - which is something that I will probably reflexively do for some time to come!
Paul
The results? The Valkyrie was almost perfect! All the pieces are still there, no cracks on any of the control surfaces (a great way to inspect rivets so to get out your bottle of Wash-Wax-All and clean the whole plane. Takes an hour, and you touch all of the exterior surfaces. Everything works, everything got lubed, and she's ready to go.
But I said "almost" perfect, didn't I? Well, there was one fiber lock nut on a 3/16" bolt that had loosened up, if you can believe that. The fiber was completely disengaged, and the nut was spinable by hand. The only REAL problem with this is that it is on the bolt at the bottom of the pilot's stick that holds the elevator pushrod to the stick.....
Now I am SURE that nut was secured during my airworthiness inspection - four people had gone over the control system before the DAR,and my DAR was particularly thorough. Had I removed the stick since then? I can't remember doing that, and even when I do, I usually pull the pivot bolt and lay the stick down, still attached to the elevator pushrod. I distinctly remember working around the stick when I checked the torque on the landing gear bolts. As I found it today, there was no washer under the nut, and all I can think of is that the nut was grabbing on the control column surface, and slowly turning on the bolt. Hard to believe, but I guess I'll never know for sure.
Of course, I have now checked every single fiber locknut in the control system, by eye and with a torque wrench. The bottom line - that is why we do Condition Inspections! You only see this bolt if you dive head-first into the cockpit, and if you have a boot on (I don't), you won't see it even then. But you can reach down and feel it - which is something that I will probably reflexively do for some time to come!
Paul