Shedding Electrical Load in a CTLSi

[andyb]

In an earlier post, I brought up some questions regarding what to do in the event of an Alternator A or Alternator B failure.  In reading the responses to my post (thank you), and doing some further research, it's clear to me that in the event of a failure of either Alternator A or B, that reducing draw on the battery is critical.  Among other reasons, this is because if the second alternator should fail, the continued running of the engine is dependent on battery power, and if either Alternator A or B fails, the battery isn't being charged any longer; drawing down the battery would directly impact how long the engine would run if both alternators fail.

This begs the question of how to reduce draw on the battery.  I don't believe this is as simple as it might seem, as it's advantageous to run the Dynon(s) and 796 on their internal batteries, and I haven't found a way to do that if power is still being supplied to them from the plane's battery.  Here's the checklist I developed:

1. EFIS breaker...off (this only disconnects power to Dynon #1; #2 will continue to run of the plane's battery)
2. Dynon#1...allow to run on it's own battery ("continue" button)
3. Transponder breaker...off
4. Nav/com breaker...off
5. GPS breaker...off (this disconnects power to the 796)
6. 796...allow to run on it's own battery ("continue" button)
7. Dynon #2...turn off by holding leftmost button
8. Lights...switches off

In this configuration, Dynon #1 will go to reversionary mode, and (at least in my plane) it will have the PFD, EMS, and Map pages.  There would be minimal battery draw, as the 796 and Dynon #1 would be running on their internal batteries.  Should it be necessary, the com, lights, or transponder could be temporarily turned back on if they were needed, and flaps would be available.

Thoughts?

Andy

[Duane Jefts]

3mm allen wrench and remove the 796 from the center console. I always carry a 3mm in the tray behind the throttle. Turn on and use for navigation.  Use ICOM a-24 Hand held radio that l always carry for backup communication. Turn off everything else.  That should get you to the nearest airport with time to spare.

Perhaps oversimplified but that is what you need in time of multiple failures.

[Cluemeister]

Is the fuel pump electrical in the CT or is it engine driven?

[Tom Baker]

For the CTLSi it is electric. All others are mechanical.

[Cluemeister]

So on a CTLSi, if  you have an alternator failure, how much time before the fuel pump stops working?  

[Duane Jefts]

Would have to lose both alternator's and then it's anybody's guess how long the battery can sustain the engine operation.  There are two fuel pumps. One is operated on and off by a switch on the panel. Only one required to run the engine which is the way you fly most of the time.  If operating on one pump and that pump fails, the engine quits immediately.  There is no gravity feed in the CTLSi.

[Cluemeister]

Of course, fuel injected.  Oops!

Thanks for the response.