nels Posted October 22, 2018 Report Share Posted October 22, 2018 i Thought this might be something everyone here might want to check out? Yesterday, while playing around with my airplane, I noticed the aileron on the right side would not travel very far towards the up position when moving it at the wing by hand. It was obviously hitting a stop of some sort. I got in the plane and tried using the controls. I was able to get it to move but heard a loud pop and then things seemed ok except I could hear metal on metal under the wing near the fuselage. I had my cousin get in the plane and work the yoke right to left while I was under the plane. I quickly found the problem. One screw in the leading wing to fuselage filler panel was rubbing the aileron control rod. So much so that it had fatigue cracked the panel next to the screw. I removed that screw and no more rubbing noise. That screw had been replaced by a larger one (see photo) and I assume it needed replacing because the original smaller screw was also hitting the rod until that threaded hole was worn out. I then removed the filler panel to get a better look. There is a thick piece of felt that is probably supposed to keep the control rod away from the sheet metal and possibly if the screw is short enough the tip may not protrude through and touch the rod. Although in my case it did. Actually that screw is located in precisely the wrong spot. Moving it an inch either forward or back looks like it would have resolved the problem. I could see someone chasing the continual lose screw with a larger one and finally create a potential real problem. From what I could see from the underside with the filler removed, the control rod has a change in section or a weld joint that catches the screw. This may not be a problem on your plane but if you have a stripped or missing screw in this location I would think this might be the reason. I’m just going to leave that screw out for now. I did note it with a marker so next annual it doesn’t get replaced with a new even larger one. Pictures show original and replacement larger screw, location of screw in filler panel and crack in panel next to screw. 2 Quote Link to comment Share on other sites More sharing options...
Yetti Posted October 22, 2018 Report Share Posted October 22, 2018 I think some of those are supposed to have #4 and backed by a tinnerman nut. The #6 or #8 you pulled out would be very wrong. 1 Quote Link to comment Share on other sites More sharing options...
Shadrach Posted October 22, 2018 Report Share Posted October 22, 2018 13 minutes ago, Yetti said: I think some of those are supposed to have #4 and backed by a tinnerman nut. The #6 or #8 you pulled out would be very wrong. Yup and impossible to get to without removing the interior. Quote Link to comment Share on other sites More sharing options...
nels Posted October 22, 2018 Author Report Share Posted October 22, 2018 12 minutes ago, Yetti said: I think some of those are supposed to have #4 and backed by a tinnerman nut. The #6 or #8 you pulled out would be very wrong. I was thinking the large one was a 6 and the correct is a number 4 as you mention. They do appear larger in the photo than I remember? Pretty certain there are no tinnerman nuts on any of the screws. Quote Link to comment Share on other sites More sharing options...
Yetti Posted October 22, 2018 Report Share Posted October 22, 2018 Probably want to check the other side. One of the painters did not know what they were doing. Quote Link to comment Share on other sites More sharing options...
nels Posted October 22, 2018 Author Report Share Posted October 22, 2018 11 minutes ago, Yetti said: Probably want to check the other side. One of the painters did not know what they were doing. That’s original paint on the screw. Plane has never been painted. Quote Link to comment Share on other sites More sharing options...
bradp Posted October 22, 2018 Report Share Posted October 22, 2018 Someone didn't know that there is supposed to be a speed nut backing the small screw on some annual some time ago... missing screws need to be replaced of course. Hmm #4 does't fit (reason why is because speed nut was gone)... eventually an oversize will catch on the sheet metal and pull it tight. Unfortunately, you found the consequence of having a mis sized screw. Quote Link to comment Share on other sites More sharing options...
carusoam Posted October 22, 2018 Report Share Posted October 22, 2018 Nel’s, What year did your plane leave the factory? See if @M20Doc has seen the missing tinnermans in the field like that... Glad you found the issue. Thanks for sharing the pics! That experience gives more reason to boxing out the controls... Best regards, -a- Quote Link to comment Share on other sites More sharing options...
nels Posted October 22, 2018 Author Report Share Posted October 22, 2018 54 minutes ago, carusoam said: Nel’s, What year did your plane leave the factory? See if @M20Doc has seen the missing tinnermans in the field like that... Glad you found the issue. Thanks for sharing the pics! That experience gives more reason to boxing out the controls... Best regards, -a- My plane is a 1978 J model. Has a ttaf of about 1200 hrs. Original paint and interior. Never on it’s belly or repaired. I really don’t think there were ever tinneman nuts behind the skin. I’d check it out tomorrow and verify but my wife and I are headed to Mexico for my son’s wedding. Tinnerman or no tinnerman, my intent was to inform that the screw no matter what size, can interfere with the aileron rod. The location just wasn’t ideal on my plane and probably on others. Probably not a particular hazard but a good thing to check out. Maybe mine was a freak? 1 Quote Link to comment Share on other sites More sharing options...
Guest Posted October 22, 2018 Report Share Posted October 22, 2018 This is a common issue with Mooney. Most of the wing to fuselage fairings are held on with #4 PK screws and small flat Tinnerman nuts. Over the years some fall out on their own or are removed by maintainers, many who don’t realize that the Tinnerman nut is not captured. The screw when reinstalled doesn’t tighten, so a larger one is installed with these results. Removing the interior to replace the missing Tinnerman is a lot of work than few want to pay for. On some Mooney’s the oval inspection panels on the leading edge of the wing are held with 8-32 countersunk screws, if over length screws are installed they will contact the aileron tube as well causing damage. I’ve replaced several tubes over the years. Nels, has your aileron tube been damaged by the screw point? Clarence Quote Link to comment Share on other sites More sharing options...
nels Posted October 22, 2018 Author Report Share Posted October 22, 2018 Thalnks, Clarence, your explanation makes sense. I really can’t see any damage to the tube so I am lucky. What I failed to mention is the felt pad that bushed the rod off the lower wing skin was no longer in the correct position and allowed the rod to drop down and contact the skin and brush up against the screw. I would think moving that fastener fore or aft would put the potential problem to bed? Quote Link to comment Share on other sites More sharing options...
nels Posted October 22, 2018 Author Report Share Posted October 22, 2018 (edited) 19 minutes ago, nels said: Edited October 22, 2018 by nels Quote Link to comment Share on other sites More sharing options...
nels Posted October 22, 2018 Author Report Share Posted October 22, 2018 Yetti, Shadrach and bradp, now I understand...a flat tinnerman. No wonder they go to larger screws once that panel is removed, nothing to keep the tinnerman in position. Looks like I have something to do next spring. Quote Link to comment Share on other sites More sharing options...
Yetti Posted October 22, 2018 Report Share Posted October 22, 2018 they can also be called speed nuts which may be more descriptive when used with sheet metal screws. I think tinnerman are threaded to be used with machine screws Quote Link to comment Share on other sites More sharing options...
Mooneymite Posted October 22, 2018 Report Share Posted October 22, 2018 Nels, good for you for discovering the control obstruction and tracking it down. Further kudos for sharing. However, I'm curious about how long this condition existed before you discovered it. Wouldn't a normal "stop-to-stop" full control check have revealed this issue immediately after the long screw was installed? Full control checks are a hot item since the G-IV accident in BED when it was discovered that the crew had only rarely done a full control check prior to takeoff. Subsequent FOQA research found that many crews throughout part 91/135 operators were not doing proper, full control checks. A good reminder for all of us. Quote Link to comment Share on other sites More sharing options...
nels Posted October 22, 2018 Author Report Share Posted October 22, 2018 36 minutes ago, Mooneymite said: Nels, good for you for discovering the control obstruction and tracking it down. Further kudos for sharing. However, I'm curious about how long this condition existed before you discovered it. Wouldn't a normal "stop-to-stop" full control check have revealed this issue immediately after the long screw was installed? Full control checks are a hot item since the G-IV accident in BED when it was discovered that the crew had only rarely done a full control check prior to takeoff. Subsequent FOQA research found that many crews throughout part 91/135 operators were not doing proper, full control checks. A good reminder for all of us. Probably easily overcome at the yoke. I found it playing around with the aeleron by hand. It must have been going on for some time as there is a crack at the screw. Hopefully others will check to see if they have a similar situation. It would be interesting to know if it’s more common than most suspect. 1 Quote Link to comment Share on other sites More sharing options...
Nippernaper Posted October 22, 2018 Report Share Posted October 22, 2018 I just got done installing some new interior trim pieces, and had the exact same symptoms when I moved the yoke afterwards. I'm thinking it might be the plastic piece between the floor and the wall, under the door and alongside the seat rail. The existing screws were quite stubby, and I used new screws which were a bit longer. I'm having a hard time believing that this could cause interference with the aileron tube, but will pull the piece to see. Amazing that someone else has the same problem on the same day (more or less). Tom Quote Link to comment Share on other sites More sharing options...
nels Posted October 22, 2018 Author Report Share Posted October 22, 2018 52 minutes ago, Mooneymite said: However, I'm curious about how long this condition existed before you discovered it. Wouldn't a normal "stop-to-stop" full control check have revealed this issue immediately after the long screw was installed? I think the problem existed before the long screw. I think it started when the felt pad moved out from underneath the control rod as I could hear it dragging along the skin after I removed the screw. I think that hole got enlarged by the small screw getting bumped by the rod and it fell out. A number 6 was substituted to pick up the larger diameter hole. Quote Link to comment Share on other sites More sharing options...
Mooneymite Posted October 22, 2018 Report Share Posted October 22, 2018 Interesting: "The NTSB report further noted that the pilots did not run a single checklist (of four) between engine start and takeoff, and in 98% of their previous 175 takeoffs, they neglected to do a flight control check." http://m.aviationweek.com/bca/lessons-bedford-gulfstream-accident-part-2 Quote Link to comment Share on other sites More sharing options...
FloridaMan Posted October 22, 2018 Report Share Posted October 22, 2018 I've had an aileron stick due to antichafe tape coming off from a gap seal, but the adhesive remained. As a quick fix, I put motor oil on a rag and wiped it down until I could get it repaired. Quote Link to comment Share on other sites More sharing options...
carusoam Posted October 22, 2018 Report Share Posted October 22, 2018 Thanks all, I get a better understanding for what to be looking for when moving the airlerons during the walk around... Best regards, -a- Quote Link to comment Share on other sites More sharing options...
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