Nukemzzz Posted February 23 Report Posted February 23 Ok, I’ve spent an hour looking and I’m turning up nothing. Time to ask for help… I suspect I’m about to fail the 500 yoke shaft AD and I’m apparently the only weirdo that doesn’t want to upgrade to the new yokes. I like the stock yokes..they are small, my iPad mounts to the pilot side using the old clock hole mount, my PC wing leveler works so I need the button, and I read that the new yokes with shafts are a bit longer which might be a problem with my short legs and growing belly…lol Is there no way to just repair the end? I can’t find anyone talking about this. Quote
Meshach Posted February 23 Report Posted February 23 Any MSC should be able to get you that repair kit. # S.B.20-205-1 or 20-205-3. Quote
47U Posted February 23 Report Posted February 23 3 hours ago, Nukemzzz said: Is there no way to just repair the end? The ‘end repair’ method of compliance (and retire the AD) is applicable only to F models sn 690001 and on. The Mooney replacement shaft’s part numbers spec’d in the SB will use the original yokes, but I do think they are 2” longer. A couple years ago, an acquaintance with a ‘65 (66?) E model ordered them and Mooney manufactured them. They weren’t cheap, though. I’m thinking it was two or three amu’s. Quote
DCarlton Posted February 24 Report Posted February 24 Any thoughts on that little set screw in the side of the yoke that seems to stabilize the yoke from rocking side to side? Mine seems to loosen up with time. I've wondered if having it loose contributes to the cracking issue. Similarly, over tightening could contribute to the cracking issues. If snug is good, it seems like it might need a thread lock if there's something that's not going to strip the Allen head later trying to remove it. Quote
hammdo Posted February 24 Report Posted February 24 If enough room, double up the screw? on mine is the pin and set screw… -Don Quote
Utah20Gflyer Posted February 24 Report Posted February 24 5 hours ago, DCarlton said: Any thoughts on that little set screw in the side of the yoke that seems to stabilize the yoke from rocking side to side? Mine seems to loosen up with time. I've wondered if having it loose contributes to the cracking issue. Similarly, over tightening could contribute to the cracking issues. If snug is good, it seems like it might need a thread lock if there's something that's not going to strip the Allen head later trying to remove it. Mine was loose when I bought my plane. I reinstalled with loctite, tight but conscious not to over tighten. That was three years ago and haven’t had any issues since. Quote
Utah20Gflyer Posted February 24 Report Posted February 24 On 2/22/2024 at 6:35 PM, Nukemzzz said: Ok, I’ve spent an hour looking and I’m turning up nothing. Time to ask for help… I suspect I’m about to fail the 500 yoke shaft AD and I’m apparently the only weirdo that doesn’t want to upgrade to the new yokes. I like the stock yokes..they are small, my iPad mounts to the pilot side using the old clock hole mount, my PC wing leveler works so I need the button, and I read that the new yokes with shafts are a bit longer which might be a problem with my short legs and growing belly…lol Is there no way to just repair the end? I can’t find anyone talking about this. What makes you think you’re about to fail the yoke shaft inspection? 2 Quote
jamesm Posted February 24 Report Posted February 24 22 hours ago, Utah20Gflyer said: What makes you think you’re about to fail the yoke shaft inspection? Another thought..... is that Maybe they just want to clear up reoccurring AD's and get them down to one. (depending vacuum pump and ignition switch replacement status). Then it would be down to one Greasing the landing gear as the only reoccurring AD (if I am understanding it correctly). Either way I could see why it's a concern. James'67C Quote
DCarlton Posted February 24 Report Posted February 24 14 hours ago, Utah20Gflyer said: Mine was loose when I bought my plane. I reinstalled with loctite, tight but conscious not to over tighten. That was three years ago and haven’t had any issues since. It's interesting that the set screw doesn't appear to show up in the parts manual; at least I can't find it. I like the idea of Locktite but it's so easy to strip Allen head screws I'm a little hesitant. Quote
Utah20Gflyer Posted February 24 Report Posted February 24 4 minutes ago, DCarlton said: It's interesting that the set screw doesn't appear to show up in the parts manual; at least I can't find it. I like the idea of Locktite but it's so easy to strip Allen head screws I'm a little hesitant. That’s an understandable concern and I had the same thought. My solution was to only use the loctite on the last portion of the screw. So I screwed it in 75 percent put the loctite on the remaining 25 percent and tightened it down. I don’t expect it to be a problem removing it. 1 Quote
Vance Harral Posted February 25 Report Posted February 25 16 hours ago, Utah20Gflyer said: I don’t expect it to be a problem removing it. Neither did we, but in our case the set screw wound up "glued" in so tight that the mechanic who performed the next inspection wound up damaging the yoke shaft trying to remove the yoke to perform the yoke shaft inspection. Talk about irony. Because of this incident, I strongly recommend against using any kind of thread locker on the set screw. Yes, it will loosen up and have to be re-tightened periodically. We keep a specific Allen wrench in one of the seat pockets to do so. 1 Quote
DCarlton Posted February 25 Report Posted February 25 A shame we don't have more info on the yoke shaft inspection AD. Where the cracks have occurred? Are they under the set screw for example? Bugs me that the little screw doesn't show up in the parts manual. It's gotta be in a drawing somewhere hopefully; not an afterthought. Bugs me that the yoke rocks at all too; shouldn't it have been a tighter fit on the shaft... hum. Quote
Utah20Gflyer Posted February 25 Report Posted February 25 1 hour ago, Vance Harral said: Neither did we, but in our case the set screw wound up "glued" in so tight that the mechanic who performed the next inspection wound up damaging the yoke shaft trying to remove the yoke to perform the yoke shaft inspection. Talk about irony. Because of this incident, I strongly recommend against using any kind of thread locker on the set screw. Yes, it will loosen up and have to be re-tightened periodically. We keep a specific Allen wrench in one of the seat pockets to do so. How much thread locker was used? Did you just do the very end of the screw like I did? Quote
Vance Harral Posted February 25 Report Posted February 25 2 hours ago, DCarlton said: Bugs me that the little screw doesn't show up in the parts manual. Do you have "late model" rams horn yokes? on your airplane? If so, you're not going to find what you're looking for in the M20F IPC, you have to look in the M20J IPC. The set screw is documented in section 27-30-00, it's an AN565-D416-H4. 1 hour ago, Utah20Gflyer said: How much thread locker was used? Did you just do the very end of the screw like I did? We applied a very light fingertip "dab" on one side of the threads, similar to what one does with anti-seize when installing spark plugs. It's entirely possible that you used less of the stuff than we did, and that you'll have no trouble later on. But when you start getting into a debate about fractional differences in the amount of thread locker you apply being the difference between damaging a yoke shaft on the next removal, I'd argue it's not worth it. The set screw is not a structural item, and the yoke isn't going to come off the shaft if the set screw is loose and allows some slop. It's just annoying if you're trying to do something like hand-fly a smooth set of lazy 8s. Quote
Utah20Gflyer Posted February 25 Report Posted February 25 45 minutes ago, Vance Harral said: Do you have "late model" rams horn yokes? on your airplane? If so, you're not going to find what you're looking for in the M20F IPC, you have to look in the M20J IPC. The set screw is documented in section 27-30-00, it's an AN565-D416-H4. We applied a very light fingertip "dab" on one side of the threads, similar to what one does with anti-seize when installing spark plugs. It's entirely possible that you used less of the stuff than we did, and that you'll have no trouble later on. But when you start getting into a debate about fractional differences in the amount of thread locker you apply being the difference between damaging a yoke shaft on the next removal, I'd argue it's not worth it. The set screw is not a structural item, and the yoke isn't going to come off the shaft if the set screw is loose and allows some slop. It's just annoying if you're trying to do something like hand-fly a smooth set of lazy 8s. Part of the issue is the yoke is aluminum which I think creates a higher chance of a problem. aluminum and thread lock can be a bad combo. The main reason I ended up using a small amount of thread lock was I tried tightening once without it and it came loose almost immediately. I agree there is some risk and would say if one uses it to use the absolute minimum amount you can. I understand that the yoke will not come off with the set screw loose but I absolutely can’t stand the feel of a loose yoke and I worry that it would create additional shock loads on the shaft. I have a couple hundred hours until my next yoke shaft inspection so I guess I’ll see then if I made a big mistake. What was the solution to getting the stuck set screw out? Quote
DCarlton Posted February 25 Report Posted February 25 3 hours ago, Utah20Gflyer said: Part of the issue is the yoke is aluminum which I think creates a higher chance of a problem. aluminum and thread lock can be a bad combo. The main reason I ended up using a small amount of thread lock was I tried tightening once without it and it came loose almost immediately. I agree there is some risk and would say if one uses it to use the absolute minimum amount you can. I understand that the yoke will not come off with the set screw loose but I absolutely can’t stand the feel of a loose yoke and I worry that it would create additional shock loads on the shaft. I have a couple hundred hours until my next yoke shaft inspection so I guess I’ll see then if I made a big mistake. What was the solution to getting the stuck set screw out? If the yoke rocks, and the set screw stops the rocking, it's likely there's a point load on the shaft where the set screw bottoms out. Would be really interesting to know where the cracks have occurred and whether it's had anything to do with over tightening the set screw. Someone here may know the history. Quote
Vance Harral Posted February 26 Report Posted February 26 5 hours ago, Utah20Gflyer said: What was the solution to getting the stuck set screw out? The mechanic first tried to drill out the screw, and when that didn't work he simply wrenched the yoke off the shaft, which of course left a big score in the shaft that had to be addressed. No one was there to stop him from ham-fisting it (we don't use that mechanic any more). It was a nightmare, and a perfect example of the unintended consequences of a "mandatory" inspection with thin justification. 1 hour ago, DCarlton said: Would be really interesting to know where the cracks have occurred and whether it's had anything to do with over tightening the set screw. In a word, no. The yoke shaft type against which the AD was issued doesn't have the set screw at all. It has a roll pin instead, and is a smaller diameter shaft. It's literally not the same thing. Unfortunately for those of us with late-model M20Fs that have the newer yokes and yoke shafts, AD 77-17-04 doesn't exempt our airplanes from the yoke shaft inspection, even though we don't have the parts on which the problem was observed. Those of us who follow the letter of the law are unquestionably performing unnecessary inspections. Those who don't perform the unnecessary inspections aren't following the letter of the law, and may get hassled by future IAs and/or buyers. Pick your poison. 1 Quote
DCarlton Posted February 26 Report Posted February 26 1 hour ago, Vance Harral said: The mechanic first tried to drill out the screw, and when that didn't work he simply wrenched the yoke off the shaft, which of course left a big score in the shaft that had to be addressed. No one was there to stop him from ham-fisting it (we don't use that mechanic any more). It was a nightmare, and a perfect example of the unintended consequences of a "mandatory" inspection with thin justification. In a word, no. The yoke shaft type against which the AD was issued doesn't have the set screw at all. It has a roll pin instead, and is a smaller diameter shaft. It's literally not the same thing. Unfortunately for those of us with late-model M20Fs that have the newer yokes and yoke shafts, AD 77-17-04 doesn't exempt our airplanes from the yoke shaft inspection, even though we don't have the parts on which the problem was observed. Those of us who follow the letter of the law are unquestionably performing unnecessary inspections. Those who don't perform the unnecessary inspections aren't following the letter of the law, and may get hassled by future IAs and/or buyers. Pick your poison. Good to know. You can’t get that from the parts manual or any of the docs I’ve seen. Quote
Nukemzzz Posted April 24 Author Report Posted April 24 Update: snugging the set screw up by around a quarter turn…and just baicially finger tight again fixed it for now. I don’t know if the screw came loose or the shaft deformed. Will monitor for now. 1 Quote
Hank Posted April 24 Report Posted April 24 On 2/24/2024 at 5:24 PM, Utah20Gflyer said: That’s an understandable concern and I had the same thought. My solution was to only use the loctite on the last portion of the screw. So I screwed it in 75 percent put the loctite on the remaining 25 percent and tightened it down. I don’t expect it to be a problem removing it. Just be sure to use blue Loctite and not red! Quote
N204TA Posted June 20 Report Posted June 20 Take it from someone who knows, don't take AD 77-17-04 lightly. I was about 450 hours since the last dye check and I felt the yoke shift when I rotated for departure. I had good control of the airplane so I continued the flight but, when I flared for landing at my destination, the control wheel came off in my hand! I was able to grab the co-pilot yoke and land "side stick" but it definitley got my attention. When I got to the hangar, I found that about 1/2 inch of the end of the shaft had complete sheared off. Fortunately, Mooney is still making parts and I was able to get the beefier replacement shafts specified in SB M20-205B in about three weeks. As long as everything was apart, I had Aero Comfort leather wrap the yokes. Expensive, but looks great. 5 Quote
Matthew P Posted June 21 Report Posted June 21 22 hours ago, N204TA said: Take it from someone who knows, don't take AD 77-17-04 lightly. I was about 450 hours since the last dye check and I felt the yoke shift when I rotated for departure. I had good control of the airplane so I continued the flight but, when I flared for landing at my destination, the control wheel came off in my hand! I was able to grab the co-pilot yoke and land "side stick" but it definitley got my attention. When I got to the hangar, I found that about 1/2 inch of the end of the shaft had complete sheared off. Fortunately, Mooney is still making parts and I was able to get the beefier replacement shafts specified in SB M20-205B in about three weeks. As long as everything was apart, I had Aero Comfort leather wrap the yokes. Expensive, but looks great. How many 10s of thousands did mooney charge for the replacement shaft and does that one have the AD as well? Quote
EricJ Posted June 21 Report Posted June 21 23 hours ago, N204TA said: Take it from someone who knows, don't take AD 77-17-04 lightly. I was about 450 hours since the last dye check and I felt the yoke shift when I rotated for departure. I had good control of the airplane so I continued the flight but, when I flared for landing at my destination, the control wheel came off in my hand! I was able to grab the co-pilot yoke and land "side stick" but it definitley got my attention. When I got to the hangar, I found that about 1/2 inch of the end of the shaft had complete sheared off. Fortunately, Mooney is still making parts and I was able to get the beefier replacement shafts specified in SB M20-205B in about three weeks. As long as everything was apart, I had Aero Comfort leather wrap the yokes. Expensive, but looks great. Yikes! Glad that wasn't worse! Quote
N204TA Posted June 22 Report Posted June 22 2 hours ago, Matthew P said: How many 10s of thousands did mooney charge for the replacement shaft and does that one have the AD as well? The new shafts were $1,275 each. I did both sides because because doing so terminates the AD and the 500-hour inspection is no longer required. 2 1 Quote
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