isaacpr7 Posted May 13, 2014 Report Posted May 13, 2014 So I finished installation of all my interior panels after a long remodeling process and now my avionics master switch will not power my avionics. The only thing I can think that would have anything to do with it is when I disconnected the speaker and lighting wires on the overhead panel. I have always had an additional switch in the circuit breaker panel that also powers my avionics as an alternate source but now it is the only way I can get power to the avionics. I also noticed that when I cranked the aircraft to run it up, the aircraft wants to shut down if I select the right magneto. When I select the left magneto I don't even get a drop on RPM. Does anyone have an idea as to what might be causing these issues? Quote
carusoam Posted May 13, 2014 Report Posted May 13, 2014 Sounds like a dead right mag. Possible broken grounding wire? When you select both, it is still running on one, the left one. So there is no rpm drop. Both and left are using only the left. Seek professional help... Make sense? As far as dual sources of voltage to supply... That's the first time I've heard of that. Can be challenging if both supplies are on at the same time. How does that sound? Best regards, -a- 1 Quote
isaacpr7 Posted May 13, 2014 Author Report Posted May 13, 2014 On 5/13/2014 at 1:52 AM, carusoam said: Sounds like a dead right mag. Possible broken grounding wire? When you select both, it is still running on one, the left one. So there is no rpm drop. Both and left are using only the left. Seek professional help... Make sense? As far as dual sources of voltage to supply... That's the first time I've heard of that. Can be challenging if both supplies are on at the same time. How does that sound? Best regards, -a- I'm a bit confused because when my MX was troubleshooting my mags in the past, he stated that when I select the left mag I am actually turning the left mag off and testing the right one. This did not make sense to me but he said that some aircraft are wired that way. Right now if I select the left mag do ot notice any RPM drop as I should when doing a mag check. As far as the second avionics master switch (installed in place of one of the circuit brakers) he stated that people back in the day would install a secondary switch in case their primary system would fail. The way this seconday switch would work before the issue started was that I could power my avionics without turning the battery switch on and the only way I could power the avionics with the battery switch on was by flipping the primary switch. Quote
carusoam Posted May 13, 2014 Report Posted May 13, 2014 Note how the ignition switch is labeled....R L B. (See if I got that right?) Whether it is left or right, one of them is not coming to work. You want both to show up on time and stay the whole day. Or they won't get paid! Note the position of the key when the engine dies. If it is pointing to the 'R' it's the right mag that's dead. Just explain what you did to the mechanic he should be able to take it from there. Now is that the right mag facing the engine or is that the right mag on the co pilot's side? You want to tell what you know. I put the key here, and it did this..... Keep in mind, I'm doing this from an aged memory... Hence my recommendation of finding a mechanic to help you with this situation. This is from the classic training on why we do a mag check and what to expect. If you have your training materials, look up the mag check for what you are experiencing. There is a recent thread on flying with one mag. I had that experience, and recommend staying on the ground until it is fixed. The other classic training indicates "that's why we have two mags". That's better for someone else.... Planes with unknown failures are not very forgiving. The failure may get worse... Ya know? If you want to check the continuity of the wires that go to the ignition switch, you will probably find the issue quite easily. It is important to have a mechanic do the actual repair. Identifying the challenge can save you some money. Trying to fix it yourself would not be recommended. The second power source was a nice idea, but you would need an engineer's level of knowledge of how to use it when it fails. Sounds like another device has gone on holiday. How are you with a volt meter? You can test circuits while on the ground with no engine running. Be safe. If you are not familiar seek professional help. Best regards, -a- 1 Quote
triple8s Posted May 13, 2014 Report Posted May 13, 2014 I had an older C model for a few years and the label or plate that was labeled had slipped so the right, left both didn't exactly line up with where the key was however, the right and the left mag MUST operate properly. Yes right should be the right one and the left ought to be the left one but "ought" and "must" are two different words with two different meanings. (Not being a smart zzz) seriously magnetos and ignition switches are one of the most important things to be right, malfunction mags and or switches will get someone chopped in half or kill the engine in the air. Don't mess with mags no kidding. People have been killed doing compression tests all it will take is a hot mag on the ground and someone turns the prop just a smidgen and one cylinder pops and they are dead. Could even be a kid walking by your plane. Get that it fixed don't monkey with it. Quote
isaacpr7 Posted May 13, 2014 Author Report Posted May 13, 2014 Thanks for the input guys. I will have my mx check it out. I just needed to know what all the possibilities would be so that when my mx starts troubleshooting I could get a warm and fuzzy that I am getting clocked for the right thing. Sent from my SAMSUNG-SGH-I337 using Tapatalk Quote
orionflt Posted May 13, 2014 Report Posted May 13, 2014 Depending on how indepth you went with the rewiring behind the panel you could have some wires mis routed. also check your ignition switch to ensure you did not wire one mag to ground or have the other mag not grounded at all. (you can do a check of the ignition switch by shutting down the engine with the switch instead of the mixture). I just rewired my airplane last yr, I labeled every wire as i ran it but as i was hooking everything back up i still found minor issues and had to retrace several wires. when it is a big project like that it is easy to mislabel or even hook the wrong wire up to the incorrect terminal. Brian 1 Quote
HRM Posted May 13, 2014 Report Posted May 13, 2014 On 5/13/2014 at 12:42 AM, isaacpr7 said: So I finished installation of all my interior panels after a long remodeling process and now my avionics master switch will not power my avionics. The only thing I can think that would have anything to do with it is when I disconnected the speaker and lighting wires on the overhead panel. I have always had an additional switch in the circuit breaker panel that also powers my avionics as an alternate source but now it is the only way I can get power to the avionics. I also noticed that when I cranked the aircraft to run it up, the aircraft wants to shut down if I select the right magneto. When I select the left magneto I don't even get a drop on RPM. Does anyone have an idea as to what might be causing these issues? I can tell you from experience that the overhead console is quite a piece of work. There is a good deal of wiring up there and it does indeed all lead back to the panel. It may not have a thing to do with your current issue, but I would drop that bugger down and trace it out with the schematic in hand. Quote
N601RX Posted May 13, 2014 Report Posted May 13, 2014 Yes and all the knife splices and old style wire (stiff and larger in diameter for same gauge wire) doesn't want to fit back up there. After I rewired everything up there with new wire it was much easier to get everything to go back in place than it previous was. Quote
rbridges Posted May 13, 2014 Report Posted May 13, 2014 my mechanic said the magnetos can be wired either way to the ignition (i.e. R can turn on or turn off the right magneto). When I had a bad plug, I had to figure out if L turned the left magneto on or off. In my case, key at L turned ON the left mag. Quote
isaacpr7 Posted May 13, 2014 Author Report Posted May 13, 2014 Thanks for all the feedback guys. My mx will take a look at it tomorrow and at least now I have some ammunition Sent from my SAMSUNG-SGH-I337 using Tapatalk Quote
isaacpr7 Posted May 15, 2014 Author Report Posted May 15, 2014 So my mx tells me he is not too savy on electrical issues but this is what we found out about the magneto: When we selected "L" on the ignition switch and checked for continuity on the right mag, it would read 000. When we selected "R" on the ignition switch and checked for continuity on the right mag, it would read in the hundreds. Based on this, my mx determined that seleting "L" on the ignition switch turns off my right mag. This tells me that if I select "R" while running up I am actually turning off my only operating mag (the left one) and this is why my engine is stalling with "R" selected. What do you guys think? Quote
triple8s Posted May 15, 2014 Report Posted May 15, 2014 I think/know this......beyond a shadow of a doubt.........if I had a mechanic that wasn't savvy with electrical issues I would find another. You are trusting your, your friends, your family's life on someone who does not know what he is supposed to know. Now......... With the switch in the both position, both P leads should read "open" with a continuity tester, with an ohm meter they should read very high. Place the switch in off position and both P leads should read zero ohms. Now, place the switch in R or L doesn't matter, one P lead will read open or very high Ohm and the other will read zero ohms. Now place the switch in the position so the other mag should be open and the other P lead should be open and the other zero ohms. If the P leads are disconnected from your magnetos the mags should grounded out, this is by design but I wouldn't trust that either. Also the p leads should be tested from center conductor to chassis ground (engine, airframe or battery) Seriously, I am no aircraft mechanic, only worked on a homebuilt for a few years CRIPES ALIVE an aircraft mechanic oughta know a magneto circuit inside and out ! 2 Quote
carusoam Posted May 15, 2014 Report Posted May 15, 2014 Second that suggestion. The description is typical of a P lead failure. Anyone trained in electronics should be able to explain this easily to a pilot. The P lead is what allows the mag to work. Grounded, it is on. Open it is off. There is danger when the P lead is grounded all the time. There is also danger when the P lead is not grounded all the time. On either R or L magneto. If you are not electrically savvy, your mechanic must be. See where I am going? You don't want to go too long without knowing the P lead failure dangers. They are too dangerous to ignore. While you are looking them up, look up effects of density altitude on take off distance. Our friend Patrick wants you to know this danger as well. Best regards, -a- 2 Quote
isaacpr7 Posted May 15, 2014 Author Report Posted May 15, 2014 Thanks for all the input guys. I think I will seek help from another mx on this issue. Sort of like a second opinion when you go see another Dr I will keep you guys posted on the outcome. Quote
carusoam Posted May 15, 2014 Report Posted May 15, 2014 Vibration and age cause wear, dirt accumulation, and/or breakage. It is highly likely that a connector is broken at the end of a wire or the ignition switch is worn or dirty. Have your new mechanic take the opportunity to show you what he finds. You will learn some new things that they don't teach in basic flight school. Density altitude, they teach in basic flight school, but many of us don't get a full feeling of the consequences until after we get some experience. Summer is coming and this issue becomes more important. We have the tools and the data now. Please review this topic as well. Best regards, -a- Quote
isaacpr7 Posted May 17, 2014 Author Report Posted May 17, 2014 Grrrrr.... At this point I am getting very frustrated trying to find a mx that can help me with the mag problem. Every time I find one I get the "I am a sheet metal guy" answer. The problem is that there is an A&P school here next to Fort Campbell and the guys who work on helicoters go to this school for a nine hour course and get their A&P license. So far, this is what I found: The P lead on the left was completely broken. After having it redone, now the will not fire up at all. But if you disconnect the "repaired" P lead, it will fire right up. The P lead on the right only has the outer wire mesh broken at the base of the round nut. I will try to crank it with the P lead off so that I can at least rule out the p lead as the only problem (being careful to stay clear of the prop and having a mx with me of course). 1 Quote
carusoam Posted May 19, 2014 Report Posted May 19, 2014 Now... Knowing what happens during the start sequence will be helpful... Do you have the 'shower of sparks' connected to one magneto? Unfortunately I don't remember these details... Best regards, -a- Quote
Alhall Posted May 19, 2014 Report Posted May 19, 2014 P leads ground the mag in the off position to keep them from firing. When you select left mag the switch opens that circuit. Select right the switch opens that circuit. Select both both circuits will be open. Break a lead and that mag will be hot and will fire. Remove a p lead on a Bendix mag it has a metal contact that will contact the case and ground the mag to keep it from firing.On the Slick mags when you remove the p lead the mag is hot and will fire. With the shower of sparks one mag has two p leads and two sets of points. One for starting (retarded) the others advanced for running. Al Quote
carusoam Posted May 19, 2014 Report Posted May 19, 2014 Thanks Al, that helps my memory a bit. Best regards, -a- Quote
isaacpr7 Posted May 20, 2014 Author Report Posted May 20, 2014 On 5/19/2014 at 3:14 AM, carusoam said: Now... Knowing what happens during the start sequence will be helpful... Do you have the 'shower of sparks' connected to one magneto? Unfortunately I don't remember these details... Best regards, -a- I do have the shower of sparks connected to the left magneto but I ruled that out since I can successfully get the engine to crank. All the SOS does is send fast pulses of electricity while cranking the engine and disengages when you release the switch. It also grounds the right magneto and left magneto P leads so that the only power supplied to the left mag is through the retard P lead at TDC in order to avoid kick back. Reference: http://www.donmaxwell.com/publications/MAPA_TEXT/Shower%20of%20Sparks/Shower%20of%20Sparks.htm Quote
isaacpr7 Posted May 20, 2014 Author Report Posted May 20, 2014 Update: Looking through the logbooks I could not find an entry for the last 500hr inspection so I decided to remove the mags and send them to a mag shop recommended by a good friend of mine. The name of the company is "Crossfire Magneto Service" in Colorado. I soke to them and they seem like the real deal. They recommended that I perform the 500hr instead of an overhaul. If they find the cost of the parts needing replacement is racking up, then they will let me know and advice me to turn it into an overhaul instead. http://crossfiremagneto.com/Crossfire_Magneto_Service/Welcome.html The only headache I will have to deal with to get my "girl" back in the air will be the electrical problem on the avionics master. Another A&P recommended that I have an avionics guy take a look at it and recertify the IFR while I'm at it. If the price is right I think this would be my best option. Quote
Marauder Posted May 20, 2014 Report Posted May 20, 2014 Well Isaac. It sure looks like you have your hands full! Keep us posted on your progress. I'm a bit surprised at the quality of the mechanics you are working with as well. Hopefully you will find one that knows the basics! As for the avionics shop, you will hopefully find people there who understand how electrons flow. There is another thread on the costs associated with an IFR certification. Should help you bench mark how much this should cost. Good luck! Sent using Tapatalk Quote
isaacpr7 Posted May 20, 2014 Author Report Posted May 20, 2014 On 5/20/2014 at 8:05 AM, Marauder said: Well Isaac. It sure looks like you have your hands full! Keep us posted on your progress. I'm a bit surprised at the quality of the mechanics you are working with as well. Hopefully you will find one that knows the basics! As for the avionics shop, you will hopefully find people there who understand how electrons flow. There is another thread on the costs associated with an IFR certification. Should help you bench mark how much this should cost. Good luck! Sent using Tapatalk Chris, You have no idea how stressfull it has been and the experience I have had with some of the local mechanics. I am determined to finish my five years left in the military and spend another two years at A&P school so that I don't have to keep going through this the rest of my airplane ownership life. Hopefully I will get tha mags back in a few days and once I install and time them they will fire right up with no issues. As for the electrical issue, sometimes I feel like ripping all the cables out and starting from scratch! LOL! I do have to say; however, she is looking beautiful inside. After all of the interior work she is looking like a new bird. In a few years I will get the exterior looking the same but for now I just want to enjoy her before I deploy again. I will keep you guys posted Thank for all the support and sharing your knowledge guys Quote
carusoam Posted May 21, 2014 Report Posted May 21, 2014 Keep on it! Flight in IMC is serious business. it requires both a solid ignition system and a reliable nav/com system. Nobody flies gliders nordo in IMC anymore? Apparently he knows that already... Best regards, -a- Quote
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