Alternator failure - checklist discussion

[cavok84]

I would pull the three strobe assemblies and just check the crimp connectors as a start. Crimps/connectors seem to be the most common issue in these planes.

Thanks, will do!

[Andy]

Here is a direct quote from the ignition system installation and operation manual -

"Dual Systems only: If you have installed an aux battery per the LSE supplied drawing, monitor your voltmeter and do not switch to the aux battery until the supply voltage of the main battery is below 6.5 Volts or the engine is not running smoothly. "

I was given the same advice by DAR Stan Franz during my airworthiness inspection.

Note that this only applies if the standard AGM (lead acid) battery is in use. An EarthX battery will shut off at much higher voltage and the ignition management strategy may need to be different.

In the same section of the ignition manual is this statement -

"If you are using Dual Plasma CD Ignition, you can turn one system off, together with all other electrical loads not essential for flight, to maximize your range with your remaining battery capacity."

I had considered this but have not yet included it in my checklist. If you did this, which would you turn off?

I decided that I would run on RIGHT only. Running on LEFT only could result in the right system spark plugs being fouled. The right system plugs need to be kept clean for use when the main battery is exhausted and emergency battery is the only ignition power source. Running on RIGHT also requires only one switch action to enable emergency ignition.

[Andy]

But I believe with the ignition in "BOTH", and the emergency switch ON, the right is disconnected from the main battery and does use the backup battery. Your point is that, unless you turn the key to R, with the MASTER OFF, and EMER ON, the left ignition is using the main battery and the right is using the backup battery--masking any deficiency within the backup battery (and using both your batteries at once). Is this correct?

Almost all correct. However, the reference to MASTER should be deleted. MASTER has no interaction with normal or emergency ignition except that it provides charging current to the emergency battery when the emergency battery is not in use.

[cavok84]

Almost all correct. However, the reference to MASTER should be deleted. MASTER has no interaction with normal or emergency ignition except that it provides charging current to the emergency battery when the emergency battery is not in use.

Yes, the reason I reference it in this post is just to clarify for the purposes of load shed (regarding lost alternator procedures). Thanks for the clarification!

[cavok84]

I had considered this but have not yet included it in my checklist. If you did this, which would you turn off?

I decided that I would run on RIGHT only. Running on LEFT only could result in the right system spark plugs being fouled. The right system plugs need to be kept clean for use when the main battery is exhausted and emergency battery is the only ignition power source. Running on RIGHT also requires only one switch action to enable emergency ignition.

When I read your question, I initially said "right", as it removes the risk of forgetting to switch ignition back to Right when selecting back up battery power. But I had not considered the potential fouling of the plugs. So, agreed.