Coopere
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- Joined
- Feb 11, 2015
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Background
Piper Aztec d model, I'm not sure if the aux voltage switch is factory or if it has been changed at some point but I have a safety switch (guarded rocker switch) on the left lower pilot side pannel, I have 2 alternator breakers (actual breakers not the pull style ones in the fuse pannel) and also have the 2 main and aux pull style fuse breakers in the co-pilot side lower pannel
Today I went for a flight and had some voltage issues. This was the 2nd flight after an extensive annual but nothing had been done to the alternators other than re securing a loose alternator bracket bolt. The first flight out of the annual was uneventful however the aircraft had sat for a few weeks prior to today's flight.
Indications were fine during the run up however shortly after takeoff my jpi 760 alarmed at a voltage drop (no charging) I then looked at the Piper ammeter (factory gauge) and noticed that when batt was selected I was showing a heavy discharge. I selected alt lft it read 0 and alt rght also indicated 0 I believe this indicates no charging on either alternator.
I then looked for my amplified procedures check list and reduced electrical loads as best I could and landed some 8min later at a local airport but not my home base. The check list I ran through was for one alternator inop light on but my Aztec doesn't have those lights. Their were no tripped breakers neither the alternators or the main or aux voltage relay breakers weren't tripped.
While on the ground I found the alternator installation checklist for failed main voltage regulator however I didn't want to run through the checklist in fear of damaging the electrical system.
I shut the aircraft down and it sat on the ramp for a few hours. I later started the aircraft back up one engine at a time I checked the alternator charging state and it seemed to be working with the left engine running alt left showed a small charge and on batt showed a charge, started right engine and alt right showed a bigger charge amount than alt left and batt showed a bigger charge amount than with just the left engine running. I shut down the left and and then checked only the right alt and it showed the same amount of charge. Then I shutdown the right engine.
About an hour later I started back up again and everything seemed to be charging so I departed for a 1.5 hr flight and everything seemed to work.
However I'm wondering if someone can shed some light on the subject? I'm also wondering if any damage can occur if the aux voltage regulator was selected if the main voltage regulator is working that was the one thing I didn't try.
The only other thing that is a bit odd is from time to time when I flip the master switch on sometimes it doesn't engage the main voltage solinoid (the clunk behind the dash) and lights up orange, usually a flip off then on again solves the issue, I'm thinking the alternator issue could be tied to a failing master switch...
Please share your thoughts
Thanks
Eric
Piper Aztec d model, I'm not sure if the aux voltage switch is factory or if it has been changed at some point but I have a safety switch (guarded rocker switch) on the left lower pilot side pannel, I have 2 alternator breakers (actual breakers not the pull style ones in the fuse pannel) and also have the 2 main and aux pull style fuse breakers in the co-pilot side lower pannel
Today I went for a flight and had some voltage issues. This was the 2nd flight after an extensive annual but nothing had been done to the alternators other than re securing a loose alternator bracket bolt. The first flight out of the annual was uneventful however the aircraft had sat for a few weeks prior to today's flight.
Indications were fine during the run up however shortly after takeoff my jpi 760 alarmed at a voltage drop (no charging) I then looked at the Piper ammeter (factory gauge) and noticed that when batt was selected I was showing a heavy discharge. I selected alt lft it read 0 and alt rght also indicated 0 I believe this indicates no charging on either alternator.
I then looked for my amplified procedures check list and reduced electrical loads as best I could and landed some 8min later at a local airport but not my home base. The check list I ran through was for one alternator inop light on but my Aztec doesn't have those lights. Their were no tripped breakers neither the alternators or the main or aux voltage relay breakers weren't tripped.
While on the ground I found the alternator installation checklist for failed main voltage regulator however I didn't want to run through the checklist in fear of damaging the electrical system.
I shut the aircraft down and it sat on the ramp for a few hours. I later started the aircraft back up one engine at a time I checked the alternator charging state and it seemed to be working with the left engine running alt left showed a small charge and on batt showed a charge, started right engine and alt right showed a bigger charge amount than alt left and batt showed a bigger charge amount than with just the left engine running. I shut down the left and and then checked only the right alt and it showed the same amount of charge. Then I shutdown the right engine.
About an hour later I started back up again and everything seemed to be charging so I departed for a 1.5 hr flight and everything seemed to work.
However I'm wondering if someone can shed some light on the subject? I'm also wondering if any damage can occur if the aux voltage regulator was selected if the main voltage regulator is working that was the one thing I didn't try.
The only other thing that is a bit odd is from time to time when I flip the master switch on sometimes it doesn't engage the main voltage solinoid (the clunk behind the dash) and lights up orange, usually a flip off then on again solves the issue, I'm thinking the alternator issue could be tied to a failing master switch...
Please share your thoughts
Thanks
Eric
