Skates97 Posted June 8, 2019 Report Share Posted June 8, 2019 Went to fly and on pre-flight the generator belt had too much play. Further looking found a bolt from the front missing. Stuck a magnet down in and fished the sheared bolt and nut out. Bolt looks odd... I did have a recent issue (a few months back) where the bolt on the backside to the bracket was missing, I think for a long time after the generator was replaced. Found that on pre-flight when the belt was loose and a little crooked. I'm thinking that missing the bolt on back allowing extra pressure on this one weakened it to where it finally broke. Here's the culprit, going to have the AP replace it next week. 1 Quote Link to comment Share on other sites More sharing options...
carusoam Posted June 8, 2019 Report Share Posted June 8, 2019 Looks like a crack initiated where the threads begin... It also looks like the bolt may have been shortened? Not a very well finished tip... Any idea if the markings indicate the right type of bolt being used? Sorry, more questions than answers... Best regards, -a- Quote Link to comment Share on other sites More sharing options...
RogueOne Posted June 8, 2019 Report Share Posted June 8, 2019 Really nice catch on a pre-flight. Well done Quote Link to comment Share on other sites More sharing options...
Skates97 Posted June 8, 2019 Author Report Share Posted June 8, 2019 No idea on the markings. I searched to see if I could find what they mean but no luck. Maybe @M20Docknows. Crack may have started over the hours it flew without the one in the back allowing it to move back and forth a little, essentially bending it ever so slightly back and forth weakening it. Quote Link to comment Share on other sites More sharing options...
Skates97 Posted June 8, 2019 Author Report Share Posted June 8, 2019 2 minutes ago, RogueOne said: Really nice catch on a pre-flight. Well done Walking around, taking to my friend about what I was checking and looking for. Exact words when I reached in and checked the belt were "Well that's not right." 1 1 Quote Link to comment Share on other sites More sharing options...
RogueOne Posted June 8, 2019 Report Share Posted June 8, 2019 I need to do more reaching. Thanks for reminder 1 Quote Link to comment Share on other sites More sharing options...
Guest Posted June 8, 2019 Report Share Posted June 8, 2019 8 minutes ago, Skates97 said: No idea on the markings. I searched to see if I could find what they mean but no luck. Maybe @M20Docknows. Crack may have started over the hours it flew without the one in the back allowing it to move back and forth a little, essentially bending it ever so slightly back and forth weakening it. The X in the middle says a standard AN bolt. Clarence Quote Link to comment Share on other sites More sharing options...
Skates97 Posted June 8, 2019 Author Report Share Posted June 8, 2019 10 minutes ago, RogueOne said: I need to do more reaching. Thanks for reminder Part of every pre-flight beginning with my PPL training. Always wondered exactly what I was feeling for back then. My CFI at the time said you know when the tension doesn't feel right. Do it every flight, you will know when it feels wrong, then start looking for why. 1 Quote Link to comment Share on other sites More sharing options...
Guitarmaster Posted June 8, 2019 Report Share Posted June 8, 2019 You're supposed to pre-flight?? Seriously though, great find!Sent from my Pixel 2 XL using Tapatalk Quote Link to comment Share on other sites More sharing options...
Hank Posted June 8, 2019 Report Share Posted June 8, 2019 1 hour ago, carusoam said: Looks like a crack initiated where the threads begin... It also looks like the bolt may have been shortened? Not a very well finished tip... Any idea if the markings indicate the right type of bolt being used? Sorry, more questions than answers... Best regards, -a- Looks like a standard tension break, from overload when the other bolt was missing. Looked again, the tip of the bolt isn't shown, just both sides of the break. I once found a 1/2" bolt laying in the bottom of my cowl. Since then (8 years ago? 9?), I grab the tip of the alternator on the right and wiggle the belt on the left on every preflight. Ain't found nothing since, but am still checking. 2 Quote Link to comment Share on other sites More sharing options...
carusoam Posted June 8, 2019 Report Share Posted June 8, 2019 Hank, My observation is of the bolt tip that is barely peeking out at the end of the nut... Of course, I compared it to my recollection of a standard bolt... from the Home Depot aisle of my favorite aircraft supply store... it looks like it might have been sawed off...and ground smooth... possibly adding stress to its history... I withdraw my observation since it probably doesn’t help any... Best regards, -a- Quote Link to comment Share on other sites More sharing options...
Hank Posted June 8, 2019 Report Share Posted June 8, 2019 2 minutes ago, carusoam said: Hank, My observation is of the bolt tip that is barely peeking out at the end of the nut... Of course, I compared it to my recollection of a standard bolt... from the Home Depot aisle of my favorite aircraft supply store... it looks like it might have been sawed off...and ground smooth... possibly adding stress to its history... I withdraw my observation since it probably doesn’t help any... Best regards, -a- That's the broken face in both photos . . . Same fracture pointing to 4:00 or so. Quote Link to comment Share on other sites More sharing options...
Skates97 Posted June 8, 2019 Author Report Share Posted June 8, 2019 2 minutes ago, Hank said: That's the broken face in both photos . . . Same fracture pointing to 4:00 or so. Yes the ends that are shown are the fractured ends, didn't take a picture of the other end. It's sitting on top of the doghouse back at the hangar. Quote Link to comment Share on other sites More sharing options...
carusoam Posted June 8, 2019 Report Share Posted June 8, 2019 I was right.... to withdraw my observation... I should have started the withdrawal sooner... Man those standard AN bolts cleave cleanly...! (Modified John Force quote... regarding Jet Hot coatings....) Thanks for letting me hang out. Best regards, -a- Quote Link to comment Share on other sites More sharing options...
Hank Posted June 8, 2019 Report Share Posted June 8, 2019 8 minutes ago, carusoam said: I was right.... to withdraw my observation... I should have started the withdrawal sooner... Man those standard AN bolts cleave cleanly...! (Modified John Force quote... regarding Jet Hot coatings....) Thanks for letting me hang out. Nah, you're still good, Anthony! 1 Quote Link to comment Share on other sites More sharing options...
mike_elliott Posted June 8, 2019 Report Share Posted June 8, 2019 7 hours ago, Skates97 said: No idea on the markings. I searched to see if I could find what they mean but no luck. Maybe @M20Docknows. Crack may have started over the hours it flew without the one in the back allowing it to move back and forth a little, essentially bending it ever so slightly back and forth weakening it. Careful when you invite Clarence, he will rag about the safety wire trimming and finishing for the baffle seals in addition to the reasons the bolt broke. Quote Link to comment Share on other sites More sharing options...
Guest Posted June 8, 2019 Report Share Posted June 8, 2019 33 minutes ago, mike_elliott said: Careful when you invite Clarence, he will rag about the safety wire trimming and finishing for the baffle seals in addition to the reasons the bolt broke. I was thinking about that, but I’m trying to turn over a new leaf! Clarence Quote Link to comment Share on other sites More sharing options...
kpaul Posted June 8, 2019 Report Share Posted June 8, 2019 56 minutes ago, M20Doc said: I was thinking about that, but I’m trying to turn over a new leaf! Clarence Don't do it...I am always impressed with your observations of small details hidden in photos. 3 Quote Link to comment Share on other sites More sharing options...
Skates97 Posted June 8, 2019 Author Report Share Posted June 8, 2019 3 hours ago, mike_elliott said: Careful when you invite Clarence, he will rag about the safety wire trimming and finishing for the baffle seals in addition to the reasons the bolt broke. There is always the thought of cropping pictures way down to keep things from the eagle eyes on MS... But then this falls in the category of the plane came that way and I never mind learning that someone previously did something "different" that can be corrected. Go ahead Clarence, leave that leaf where it is and educate me. 3 Quote Link to comment Share on other sites More sharing options...
cliffy Posted June 12, 2019 Report Share Posted June 12, 2019 Education Warning- The safety wire twists shown in the photo should have been folded back on themselves to avoid and chance of finger piercing when working inside the cowl. Its standard A&P practice on safety wire. It shows a non A&P did the work. Quote Link to comment Share on other sites More sharing options...
mike_elliott Posted June 12, 2019 Report Share Posted June 12, 2019 2 hours ago, cliffy said: Education Warning- The safety wire twists shown in the photo should have been folded back on themselves to avoid and chance of finger piercing when working inside the cowl. Its standard A&P practice on safety wire. It shows a non A&P did the work. Not necessarily, Cliff, I have personally corrected a lot of A$P's improper safety tie (and zip ties to engine mounts etc) techniques on my old F. Sometimes, they just do what is easiest for them and forget the best practices they should. Fortunately, most are not that way. If done by a non A&P, then the inspecting A&P should have said something, heh? Quote Link to comment Share on other sites More sharing options...
Yetti Posted June 12, 2019 Report Share Posted June 12, 2019 3 hours ago, cliffy said: Education Warning- The safety wire twists shown in the photo should have been folded back on themselves to avoid and chance of finger piercing when working inside the cowl. Its standard A&P practice on safety wire. It shows a non A&P did the work. I was going to say that. Saw that skin cutting mistake before I saw the bolt. Does the Generator have two bolts that hold it to the mounting bracket or one? The alternator on the F has two bolts that attach tot he bracket. More work, but some redundancy. Quote Link to comment Share on other sites More sharing options...
cliffy Posted June 13, 2019 Report Share Posted June 13, 2019 Yes Mike I agree ! Quote Link to comment Share on other sites More sharing options...
Guest Posted June 13, 2019 Report Share Posted June 13, 2019 The safety wire installation while impressive could be improved upon with some 1/8” diameter large head rivets, or some AN 470A4 series rivets and some 1/8” area washers to hold the baffle sealing tapes on. Clarence Quote Link to comment Share on other sites More sharing options...
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