Piper 28 Stall horn circuit breaker popping

WannFly

WannFly

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i had my plane down for annual and today as my mechanic was about to sign off for service he found the circuit breaker of the stall horn keeps popping. while he is trying to find out the root cause i was wondering if any of you here have any ideas?

he checked the lights/horn/pitot heat right before taking her down for annual and everything was working. so we are kind of baffled with his sudden irrational behavior from the circuit breaker.

he did install JPI 830, but its connected to a diff breaker on a diff bus. not a dead short, he said he is getting about 35 ohms

ideas?
 
GlennAB1 said:
Any repairs installed with blind fasteners during annual? Had one, once upon a time, they drilled into a wire bundle.
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he didnt even go near the stall wires
 
Sounds to me like you have a pinched wire somewhere, likely behind the panel. Your mechanic may think he went nowhere near the stall warning wires but he had to without realizing it or there was a prior problem that got disturbed and is now making itself known.
 
mondtster said:
Sounds to me like you have a pinched wire somewhere, likely behind the panel. Your mechanic may think he went nowhere near the stall warning wires but he had to without realizing it or there was a prior problem that got disturbed and is now making itself known.
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This. ^
 
WannFly said:
he didnt even go near the stall wires
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If he installed a JPI EDM 830 he had to run a LOT of wires for all the signals and bring power from the breaker panel. I'll bet he had to tap into the MP gauge line on the right side of the panel for that signal (it's usually a transducer that fits a tap into the tubing line. That's just one example. Bottom line, lots of under/behind the panel work.

Highly likely something in the old wiring was disturbed during that process. But not an absolute certainty. No better option than to do a systematic trace with a multimeter.
 
35 ohms he got. 14 volts divided by 35 ohms is only about 0.4 amps. There's an intermittent short somewhere or the breaker is totally shot. Put the ohmmeter on that line again and start wiggling wires.
 
So this is what my mechanic did.... took the whole wire out, checked for kinks and pinches. Hooked it back, no more popping. Guessing it was pinched somewhere. Flew for 1.5 hrs, nothing popped. I will keep an eye out next few flights and hopefully nothing pops. It would suck big time if that thing pops and go unnoticed and I am practicing stalls

Sent from my SM-G935V using Tapatalk
 
WannFly said:
So this is what my mechanic did.... took the whole wire out, checked for kinks and pinches. Hooked it back, no more popping. Guessing it was pinched somewhere. Flew for 1.5 hrs, nothing popped. I will keep an eye out next few flights and hopefully nothing pops. It would suck big time if that thing pops and go unnoticed and I am practicing stalls

Sent from my SM-G935V using Tapatalk
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By now you should have no difficulty feeling the approach to a stall in your Cherokee. Unless you are doing something really stupid they don't sneak up on you in one of those! ;) :)

Glad to hear you got it sorted, however. :thumbsup:
 
Ignorant question on my part: My '69/70 Cherokee has a light but no horn. Common?
 
WannFly said:
So this is what my mechanic did.... took the whole wire out, checked for kinks and pinches. Hooked it back, no more popping. Guessing it was pinched somewhere. Flew for 1.5 hrs, nothing popped. I will keep an eye out next few flights and hopefully nothing pops. It would suck big time if that thing pops and go unnoticed and I am practicing stalls
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So, replace the wire, its insulation has been compromised.
 
Pa28-180 light only. 1966... anyone upgrade to horn??
 
Happy Thanksgiving. I’m asking if anyone has upgraded from stall light (only) to horn, and if so, apx cost and involvement. thanks
 
Chad Gingras said:
upgraded from stall light (only) to horn, and if so, apx cost and involvement. thanks
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I don't have any particulars, but one place you can start is contact Piper Support (https://www.piper.com/contact-us/) and inquire on your OEM options. Factory options sometimes involve less paperwork and more part cost, but not always. Be sure to include your aircraft serial number. Then, discuss with your AP/IA on install costs and any other options like a STC kit or other type of alteration. This will give you costs and availability specific to your aircraft and possibly offer the option to install at your next annual? Good luck.
 
Hello all. I realize this is an old thread - but thought what the heck. I have a 75 Arrow with only a dim stall warning light. The light is really hard to see during stall practice. Has anyone upgraded their light to a brighter one? I was thinking maybe I could swap it out with an LED. This bulb might not be of a replaceable type, I'm not sure?? Another option would be to add a stall warning horn in line (parallel?) with the light. When the light comes on, so would a horn??? Thoughts on this would be appreciated. I understand the pilot lawyers will come out because that's what they do, however, if you stop and think about for just a minute - you'll understand that I am actually trying to create a "more safe" environment.
 
Pickle said:
Hello all. I realize this is an old thread - but thought what the heck. I have a 75 Arrow with only a dim stall warning light. The light is really hard to see during stall practice. Has anyone upgraded their light to a brighter one? I was thinking maybe I could swap it out with an LED. This bulb might not be of a replaceable type, I'm not sure?? Another option would be to add a stall warning horn in line (parallel?) with the light. When the light comes on, so would a horn??? Thoughts on this would be appreciated. I understand the pilot lawyers will come out because that's what they do, however, if you stop and think about for just a minute - you'll understand that I am actually trying to create a "more safe" environment.
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Check the airplane's parts catalog and the bulb to see if the right bulb is installed. Someone might have replaced a dead bulb with "one that looks right." Maybe even a 24-volt bulb in a 12-volt airplane. It happens.
 
Great idea - start with the easy solution! I was chatting with some guys here and we struggled to find the bulb type or number. We are thinking it might be 328 or 330 peanut bulb style. I will pull it out and try to match it up.
 
Pickle said:
Hello all. I realize this is an old thread - but thought what the heck. I have a 75 Arrow with only a dim stall warning light. The light is really hard to see during stall practice. Has anyone upgraded their light to a brighter one? I was thinking maybe I could swap it out with an LED. This bulb might not be of a replaceable type, I'm not sure?? Another option would be to add a stall warning horn in line (parallel?) with the light. When the light comes on, so would a horn??? Thoughts on this would be appreciated. I understand the pilot lawyers will come out because that's what they do, however, if you stop and think about for just a minute - you'll understand that I am actually trying to create a "more safe" environment.
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Adding the horn should be easy and fairly cheap. I believe that the Sonalerts run about $35 from Mouser and would just need to be wired in parallel to the stall light. My Davtron clock suggested a specific model. The Mallory Sonalerts come with a variety of sounds and a range of db. Check with your IA and the manufacturer on which one to get. https://mspindy.com/SearchSeries.aspx?Code=30EVC
 
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The Piper light sucks. One Cherokee I looked after had a buzzer wired in with the light. The light worked as designed, the buzzing must have been a mosquito. ;)
 
Thank you kshaw, that website was great. It allowed me to see and here the different buzzers. Personally, I like the 2000 HZ freq the best. I found that most stall warning buzzers run at around 90 dba and anywhere between 2000-3000 hertz. I did find on Amazon a red flashing LED indicator light with buzzer all in one (search uxcell panel mount flashing alarm). I think the buzzer tapped into the light wires would be fast easy and safer.

I agree JAWS, the light sucks. I am going to make sure the correct bulb is installed as mentioned earlier. I might even be able to swap to a brighter LED???
 
Ok, For those that are interested in following along...I purchased the Mallory SC616NLR. It is a DC, maximum 16V, draws only 22mA, is 95 dba at 16V - so I assume it will be slightly less at 14V. It's a constant tone (no pulse or siren) at 2900 +/- 500 Hz...This is perfect! I plan on wiring right into the light behind the dash.
 
Don't "wire it it" that's illegal Adapt a bayonet male device to the base of the bulb thence to the Mallory thence to a ground. the bulb is always "hot"; the stall vane closes the ground. A small disc under the bulb is all you need (insulated edges), You don't want NTSB saying you had made permanent non STC alteratation to the circuit....when the accident investigation occurs.

NON permanent, removable changes are legal. Soldered, not so much.
 
Great info, thank you. Unfortunately, I am not following your suggestion exactly. Are you thinking something like this?
47625_5.jpg

My thought was to tap into each the hot wire and the ground (at the light) with one of these:
3a2b61cc87e158d362bf96a8a1522679d165e8f5_original.jpeg

This uses a male spade connector - so arguably this is not permeant. Thoughts on this approach?
 
Not sure you will see my last line because it is buried next to the photo of the t-tap. So, I thought I would include it again, just in case:

"This uses a male spade connector - so arguably this is not permeant. Thoughts on this approach?"
 
I don't think the T tap is approved, and is permanent.
 
Don't ever use those scotchlok or similar taps in an airplane. Arguably don't use them anywhere, they suck, but absolutely do not use them in an airplane.
 
bluerooster said:
I don't think the T tap is approved, and is permanent.
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I agree. Those type connectors work fine with auto type circuitry but wiring on a plane is different. The plane wire insulation is not as thick as auto insulation and harder. The Mallory Sonalerts are polarity sensitive. You would need to connect the + side of the sensor to the positive side of the bulb socket and run the ground wire to the grouding block on your plane or ground it locally. You can easily fabricate a bracket for the sensor with Kodex plastic. Here is one I made for another project. You will need your AP to sign off so consult with him on the best way to do it.
 

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Excellent! I appreciate all the wisdom and experience on here - it's incredible. Thank you so much.

Ok, so no wire taps. Here is what my light socket looks like (see attached photo) - it has two tabs +/- with what I assume is either a push on connector or individual female spade connectors. If I can't solder, from an earlier post, how do you recommend that I connect the positive wire? Would it be ok to swap the female spade connector with one of these multi-stack and connect that way? I want to have a game plan before I talk to my A&P / IA - he is by the book, so I need to have a solid plan going into the project.

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I'd definitely check the bulb in your light. A 28V incandescent bulb in a 14V system works, it's just dim (not sure what bulb goes in the particular socket off the top of my head, but for example a 328 will go right in where a 330 will go, it will just be dimmer... putting in a 330 where should be a 328 will be really bright for a moment before it burns out).

As far as adding the audible alert, your A&P will still need to sign this off as minor alteration, so I'd just discuss it with them, they may prefer a splice. Those piggy back terminals (160834-2, 9-160463-2) are OK, but I personally prefer other connection means.
 
Pickle said:
Excellent! I appreciate all the wisdom and experience on here - it's incredible. Thank you so much.

Ok, so no wire taps. Here is what my light socket looks like (see attached photo) - it has two tabs +/- with what I assume is either a push on connector or individual female spade connectors. If I can't solder, from an earlier post, how do you recommend that I connect the positive wire? Would it be ok to swap the female spade connector with one of these multi-stack and connect that way? I want to have a game plan before I talk to my A&P / IA - he is by the book, so I need to have a solid plan going into the project.

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These are the wrong size. Look for ones with red insulation. The insulation color is matched to the gauge of the wire used and most low amp requirements in aircraft like this are red. You can easily crimp the wire to the sensor and the wire to the bulb together into one connector and that is likely what your A&P will do. He will also use one of the racheting crimpers rather than one of the cheap ones that just rely on brute force. Without the racheting mechanism, you cannot assure that you have a good crimp. Your AP may let you do the job and agree to sign off but you will need to demonstrate to him that you know how to properly crimp the connectors, are using aviation wirings, and using the right tools. Your AP will want to inspect your work before signoff to assure that your wiring does not interfer with flight controls. Watch some of the EAA webinars for homebuilders and you should be ready to have that discussion with him. You may have to join the EAA to watch the videos. https://www.eaa.org/videos/webinars
 
100% agree with everything you said, thank you. When I posted the image of the "blue" multi-stack terminal - I wasn't referring to the gauge (however, you are absolutely correct with your comments) - I am trying to determine a wiring plan that most folks agree with for making this connection. The problem that I am reading is how do I "connect" this horn to the aircraft electrical system without "violating" the rules. I was told soldering is out and T-Taps are not good or recommended...So, I suppose I could just use butt connectors, but at that point, isn't that just like soldering? The multi-stack terminal seems like it has the best of both worlds.

Another suggestion I received was to use one of these Wago three conductor splice (see photo below). The Wago unit is quite small (slightly larger than wire twist on caps or slightly bigger than a thumb nail) and works on wires from 12-24 AWG. I am assuming based on some limited experience that my airplane's smallest gauge wires is 22...But, I am not certain of this. The benefit of the Wago connector, all I would need to do to remove the horn would be to lift the lever, pull the wire out and close the lever leaving an empty slot; done, not permanent. Thoughts on these?

Again, thank you to everyone. I have enjoyed the discussion and leaning on folks experience, opinions and advice. This is a great community!
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Pickle said:
The problem that I am reading is how do I "connect" this horn to the aircraft electrical system without "violating" the rules.
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FYI: unless your A&P mechanic performs this work with the materials he selects, you as owner are "violating the rules" and the terms/conditions of your AWC.
 
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