Piper 28 Stall horn circuit breaker popping

Discussion in 'Maintenance Bay' started by WannFly, Jun 26, 2017.

  1. Ryan Klems

    Ryan Klems Pre-takeoff checklist

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    The Wagos are great for house wiring, much better than wire nuts. Not appropriate for use in an airplane. I think you are severely overthinking this. Wiring in the buzzer to your stall light is (IMHO) a simple minor alteration. You said you were getting your A&P involved, let them tell you how they want you to attach it and mount it, do that, have them look at it and get the log book sign-off. Then it's a permanent minor alteration, no violation of any rules. You don't need an STC or field approval or anything here (again, my opinion, your A&P could potentially have a different opinion, but nothing here falls under 43 Appendix A, etc), this is just a simple minor alteration made legal with a log book entry by your A&P. Trying to make this some "temporary" install isn't worth the mental gymnastics.
     
    Last edited: Feb 2, 2021
  2. Pickle

    Pickle Filing Flight Plan

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    Agreed. My A&P is a great guy, happy to help, however, he is by the book. If I go to him generally asking that I want a stall warning horn added in, it WILL BE 1000's of dollars and then that is that. However, I have learned after working with this guy, that if I come to him with a peer reviewed solution, I have a significantly better chance of him 1. being willing to look at the problem from my perspective and 2. find a solution, if he doesn't agree with the community, that he feels meets the regulations and as a result only cost a few hundred bucks. I can't be the only one who has experienced this, no?
     
  3. Hang 4

    Hang 4 Cleared for Takeoff

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    Adding a audible stall warning to the "light only" PA28 is a very common modification. If your AP has Piper experience, he has likely done this a few time already.
     
  4. Bell206

    Bell206 En-Route

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    In my experience, no. I also prefer going "by the book" but my rates do not change from $1000s to $100s because of what the "community" says. I believe there is more to this story or maybe you need a different APIA.:rolleyes:
     
  5. Pickle

    Pickle Filing Flight Plan

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    I am learning that it is difficult for me to communicate via chat board versus sitting down and having a regular old conversation.

    My A&P charges $100 per hour. When you want to do something like add a stall warning horn - my previous experience with working with him is that he will go to Piper parts catalog, find the part number and quote/buy the horn from distributor. In my case, the part number is 565-407 and it sells for $1133.00 + shipping. So, he will probably charge me 10-15% on the parts (usually does) and the labor to install, my guess is 2 hours. So, when I say thousands, it is more like $1500. On the other hand, if I come to him with an idea and a potential solution to the idea, he is much more willing to engage outside the earlier scenario. Maybe I am dealing with a strange A&P, heck maybe I am strange -- I don't know. That all said, I agree with you Bell206, I believe my A&P IA - could care less about what others think, the info is for me to have reasonable ideas to present to bypass scenario #1. Does that make sense?

    In the end, I am new here to the forum...Maybe, I am pushing buttons? I hope not! But, as you all know, the aviation world is full of rules that quite frankly are all shades of gray. I don't want to or will intentionally violate a rule - and I suspect nor do you. The question is, how do I do what I want to do within the rules? Kind of like paying taxes, how do I minimize my tax burdens within the limits of the laws.
     
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  6. kshaw

    kshaw Pre-takeoff checklist

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    You are permitted to do work on your own plane under the supervision of your AP. A consultation with the AP on your approach to the task and the parts and tools you plan to use are appropriate. No requirement that the parts have to be provided by AP but they do have to be approved by the AP before he will agree to signoff. The AP signs the logbook as if he did the work. Nothing wrong with this and many pilots aspiring to become an AP use this technique to gain the experience needed to take the tests.
     
  7. kshaw

    kshaw Pre-takeoff checklist

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    Finding the AP willing to do the signoff may be difficult. My suggestion is to join the EAA and become acquainted with the local chapter. Many of the homebuilders are APs or know an AP that is willing to work with someone that wants to do a modication like you are suggesting. They will work with you. If you plan to do more of this in the future, keep a log of all the work you have done under the supervision of an AP and you can eventually take the AP yourself. I know a lot of guys that get their AP license only so they can work on their own plane.
     
  8. Bell206

    Bell206 En-Route

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    Now it does. Prior to that it didn’t nor were some of your previous replies going in the right direction. ;)

    As to the rules being gray, if you take the time to actually read them and their associated guidance documents, you’ll find they’re much closer to black and white than gray. It worked for me so I’m sure it will work for you, if you so choose.
     
  9. Bell206

    Bell206 En-Route

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    Well considering I’ve provided owner-assisted maintenance for a number of years, I’m well aware of the process. But up until the details Pick provided in his last posts, his horn mod direction was not so defined from a regulatory aspect. Hence my posts to assist in changing his direction which he has since confirmed.
    While consultation is always paramount in these scenarios, don’t forget there is still is a requirement for the mechanic to be physically present during the key processes of the work performed.
    Not quite. The person actually performing the work must also sign the entry. The AP signature approves that work in addition provides the approval for return to service for that work.;)
     
  10. Dan Thomas

    Dan Thomas Final Approach

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    Installing a buzzer and connecting it to the existing light can lead to problems. The breaker for the stall warning might be two amps or five amps and the wire to the switch and light are sized to handle that much current so they don't smoke before the breaker pops. Then you install a cheap little buzzer with its 24- or 28-gauge wire, maybe, wire that's sized to carry the small current to operate the buzzer. The buzzer later starts shorting internally or a wire chafes and shorts, and now those little wires get red-hot and make things rather uncomfortable for the pilot.

    A minor mod with major risk if it's not done right. AC43.13 was published for good reasons.

    I've also encountered battery minder harnesses attached to the battery terminals and left hanging, and no fuse anywhere in the harness's positive line. If it shorts against something, there's going to be a fire. The insulation on those harnesses is PVC, not the aircraft-grade fire-resistant Tefzel.
     
  11. Pickle

    Pickle Filing Flight Plan

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    Update...So, I made it over to the plane today and removed the light to determine what bulb type and why it was so dim. After removal I found that it had the correct lamp inside: 12V Part # 330. Interestingly, after I put the lamp back in and tested to make sure it was working - the light was significantly brighter. Maybe twice as bright. I can only think that perhaps it wasn't getting a "good" ground? Crazy! For those that are following along my trials and tribulations, I have included a photo of the newly bright lamp. Also, I spoke with my A&P today and he was very open to the idea of adding the "horn." He said he was going to do a little research, but on initial thought, with a "5 AMP stall warning breaker", he didn't think that there would be any issues or problems. He also said that he has installed a few buzzers a long time ago - like over 10 years ago. When asked about how he would wire, he said that he uses aviation grade terminals with Tefzel heat shrink. Needless to say, I am relieved that the light is brighter and that I won't have to spend lots of cash ($1500) for a simple horn. I will let you know how this progresses - if anyone is interested.

    Thanks again to everyone for all the suggestions and feedback. It certainly felt like a challenge at points, but that is what I think these forums are for - to discuss and work through ideas to find solutions.
     

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  12. 3393RP

    3393RP En-Route

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    Indeed. Insulation displacement connectors are bad news.
     
  13. Dan Thomas

    Dan Thomas Final Approach

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    Yup. The metals of the bulb case, the lead point on the bottom, the socket and the contact button in it all oxidize with age and introduce resistance to the circuit. Nav light failure is often due to this.