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  #11  
Old 04-27-2021, 01:17 PM
agent4573 agent4573 is offline
 
Join Date: Aug 2019
Location: Mountain view
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If your alternators are automatic switchover, how do you test that the backup is working on your preflight without a switch to turn off the primary?
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  #12  
Old 04-27-2021, 02:41 PM
rapid_ascent rapid_ascent is offline
 
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I do have individual switches for the 2 alternators so I can turn off either. Master/Primary Alt and Endurance Bus/Backup Alt.

I was referring more to not needing a cross-feed switch for my endurance bus. In the event of a primary alternator failure I can elect to reduce loads and then live on the endurance bus. Or at least that is the plan. The B&C regulators are setup so that the voltage for the backup is set lower than the primary for the automatic alternator switchover.

BTW I'm essentially following Z-13/20.
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  #13  
Old 04-27-2021, 03:22 PM
BobTurner BobTurner is offline
 
Join Date: Dec 2011
Location: Livermore, CA
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Quote:
Originally Posted by lr172 View Post
That is just scary. It is really a shame that as an industry, we do not train pilots to understand the basics that are required to execute a safe flight. I personally believe that we should not allow pilots to take off without understanding the basics of how an engine an electrical system works. We can't just pull over and call AAA.

Larry
Many of us have forgotten how truly lacking some pilots’ knowledge of such basics really is. Some years ago, a local flying club private pilot hopped into their completely stock (mags, etc) 172.
1. After engine start, he noted the red idiot light on (indicating the over voltage relay had tripped, as sometimes happens on Cessna starts. You reset it by cycling the master, as well documented in the POH). But this pilot decided it didn’t matter!
2. Ammeter was showing a discharge. He never looked or, again, chose to ignore it.
3. After flying a while, he noted the radios were failing. He returned for landing, the flaps wouldn’t extend. He landed long, blew out both main tires when he locked up the brakes, went off the end of the 4000’ runway, minor damage.
4. When asked why he didn’t go around and set up for a proper no-flap landing, he replied, “I realized the electrical system was failing, and, with no electricity, I knew the engine could quit (!) at any second.”

Now, legally, this guy could be PIC in an electrically dependent all-electronic ignition RV. And, even some builders have issues. I heard a builder give the new owner of the plane what I think was very bad advice on how to start the engine (non-retard, non-impulse back up mag ‘on for start’). Sometimes EAB is the wild west, where anything goes. I have no idea how to fix this without impacting EAB’s freedom to make your own choices (ignition, etc).
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  #14  
Old 04-27-2021, 03:39 PM
agent4573 agent4573 is offline
 
Join Date: Aug 2019
Location: Mountain view
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Quote:
Originally Posted by rapid_ascent View Post
I do have individual switches for the 2 alternators so I can turn off either. Master/Primary Alt and Endurance Bus/Backup Alt.

I was referring more to not needing a cross-feed switch for my endurance bus. In the event of a primary alternator failure I can elect to reduce loads and then live on the endurance bus. Or at least that is the plan. The B&C regulators are setup so that the voltage for the backup is set lower than the primary for the automatic alternator switchover.

BTW I'm essentially following Z-13/20.
Gotcha. That makes a lot more sense. Initially I thought you got rid of the alt1+2 on/off switches. I couldn't figure for the life of me how getting rid of your alternator switches would be helpful.
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  #15  
Old 04-27-2021, 04:38 PM
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Walt Walt is offline
 
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Quote:
Originally Posted by agent4573 View Post
Gotcha. That makes a lot more sense. Initially I thought you got rid of the alt1+2 on/off switches. I couldn't figure for the life of me how getting rid of your alternator switches would be helpful.
I have built a number of panels with backup alt but no on/off switch for the BU. When I feel like the owner is not system savvy, I think it's easy/safer to just leave the BU 'on' all the time, it will pick up the load automatically when the voltage drops from the normal 14.5 to 13.5 and the yellow voltage warning light illuminates letting him know the system is not normal/running on backup alt.
If you want to kill alt 2 just pull the field CB.
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  #16  
Old 04-27-2021, 04:42 PM
PhatRV PhatRV is offline
 
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Location: Buena Park, California
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Default What to do with CI Finding?

Quote:
Originally Posted by Walt View Post
Kinda scary stuff for me...

Finishing up a Condition Insp on an aircraft for a new owner today, the aircraft is a 'modern' RV, recently purchased with 390, glass panel, full EFII, dual batteries and dual plane power alternators, etc.
Slightly off topic: when you find these serious safety findings during the CI for EAB, what do you do? Can you ground the airplane like an AI or you just document the findings and give them to the owner?

Thanks
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  #17  
Old 04-27-2021, 04:55 PM
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Mike S Mike S is offline
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Location: Dayton Airpark, NV A34
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Quote:
Originally Posted by Walt View Post
I think it's easy/safer to just leave the BU 'on' all the time, it will pick up the load automatically when the voltage drops from the normal 14.5 to 13.5 and the yellow voltage warning light illuminates letting him know the system is not normal/running on backup alt.
This is how I flew the RV 10, and the new Rans S21 will be the same. I did install separate ALT switches, but only to be able to turn off a faulty unit.

Worked just fine with the RV for 6 years or so.
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  #18  
Old 04-27-2021, 05:25 PM
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Walt Walt is offline
 
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Quote:
Originally Posted by PhatRV View Post
Slightly off topic: when you find these serious safety findings during the CI for EAB, what do you do? Can you ground the airplane like an AI or you just document the findings and give them to the owner?

Thanks
An AI (which I am) cannot ground an aircraft, only a fed can do that.

I have a standing agreement with all my customers, if you bring it to me we fix everything (airworthiness) that needs to be fixed, period.
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Specializing in RV Condition Inspections, Maintenance, Avionics Upgrades
Dynamic Prop Balancing, Pitot-Static Altmeter/Transponder Certification
FAA Certified Repair Station, AP/IA/FCC GROL, EAA Technical Counselor
Authorized Garmin G3X Dealer/Installer
RV7A built 2004, 2000+ hrs, New Titan IO-370, Bendix Mags
Website: ExpAircraft.com, Email: walt@expaircraft.com, Cell: 972-746-5154

Last edited by Walt : 04-27-2021 at 05:33 PM.
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  #19  
Old 04-28-2021, 12:31 PM
Canadian_JOY Canadian_JOY is offline
 
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Location: Ontario, Canada
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Quote:
Originally Posted by Walt View Post
I have a standing agreement with all my customers, if you bring it to me we fix everything (airworthiness) that needs to be fixed, period.
Now THERE's a sound business practice. If you can't accept it, go somewhere else. I work the same way, grading defects into "must fix / airworthiness", "should fix very soon if not in this visit", and "non-impacting, fix at a point of convenience". Nothing on the "must fix" list can be deferred - it gets fixed now or the airplane doesn't fly. This simple technique works very well if stated and agreed to up front.
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  #20  
Old 04-28-2021, 02:35 PM
Ralph Inkster Ralph Inkster is offline
 
Join Date: Feb 2008
Location: Calgary, Alberta
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Quote:
Originally Posted by Walt View Post
I have built a number of panels with backup alt but no on/off switch for the BU. When I feel like the owner is not system savvy, I think it's easy/safer to just leave the BU 'on' all the time, it will pick up the load automatically when the voltage drops from the normal 14.5 to 13.5 and the yellow voltage warning light illuminates letting him know the system is not normal/running on backup alt.
If you want to kill alt 2 just pull the field CB.
Is that the plan for this plane's situation? Hope so.
Have you gone as far as to review the battery schematic to insure it makes sense for it's 'advanced systems' also? And (NOT really your job, but...) that the owner now fully knows the workings, reasonings & operation of all those switches...

-

I once had a plane come in with 2 batteries wired in parallel (hard starting, actually burnt out the starter or 2) and insisted he had redundant batteries & could switch one off...
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