Mike
Naturally I would never leave the pumps on after parking because I always
use and follow my checklists :-). Actually mine are quite noisy Bosch
injection pumps so its probably not likely.
Thanks for your comments, much appreciated and valid points.
My main aim is to simplify the electrical system precisely for safety
sake. I have a secondary aim which is my flight to the US. There are some
quite long legs over water or jungle (which amounts to the same thing). I
want to be able to maximize the electrical range by switching off all
unnecessary electrical loads. For me this includes everything except what
is needed to run the engine range as my back up batteries and handheld
devices will take care of the flying aspect.
So ideally Id like to have one buss which I can switch off to achieve this
minimal electrical load. At the moment I think the only things which
require separate switches are
- Master
- mags
- Avionics 1 - ADSB XPNDR RADIO Intercom
- Avionics 2 - AP servos in case they start acting strangely I
would like to able to switch them off separately.
- Fuel Pumps x 2 - sometimes on the ground one wants to fiddle with the
EFIS without the pump draining the battery.
- Landing and Anti Col lights
Connecting a pump to the battery might be a moot point because sudden and
complete alternators failures are very rare and also my Rotax 912 turbo has
a mechanical pump which in theory should maintain up to 29 in at sea
level. I have yet to test this.
Will
William Daniell
LONGPORT
+57 310 295 0744
On Thu, Apr 5, 2018 at 7:32 PM, Mike Gregory <m.j.gregory@talk21.com> wrote:
> Hello Will,
>
>
> You could connect the second fuel pump direct to the battery, via a
> fuse/CB and switch as for the trim circuit, but why would you wish to?
>
>
> In the event of alternator failure, unless you have a low-capacity main
> battery, you have plenty of time to shed loads according to how long you
> need to keep airborne. In the event of a forced landing and turning off the
> main bus with the master switch, the electric trim is kept operational to
> avoid heavy stick forces, but this logic does not apply to the fuel pump.
>
>
> If the engine has stopped and you are making a forced landing, a single
> action to turn off the master switch before contact with the ground will
> kill all electrics (except the trim and your built-in standby batteries)
> and minimise the risk of a post-impact fire caused by an electrical short
> circuit and hefty current from the main battery. In particular, it will
> also stop the fuel pumps from potentially squirting fuel all over the
> wreckage, without your having to remember to switch off your fuel pump off
> separately.
>
>
> Of course, you would never shut down the engine after parking, turn off
> the master switch and forget to turn off your fuel pump!
>
>
> Best wishes,
>
>
> *Mike*
>
> Dr Mike Gregory
>
> Europa Club safety officer
>
> 01480 451655
>
> 07885 355765
>
>
> *From:* owner-europa-list-server@matronics.com [mailto:owner-europa-list-
> server@matronics.com] *On Behalf Of *William Daniell
> *Sent:* 05 April 2018 17:25
> *To:* europa-list@matronics.com
> *Subject:* Europa-List: Rotax 914 Electric fuel pumps
>
>
> I have the Europa System with one of the pumps connected direct to the
> alternator and the other to the bus.
>
>
> I get the logic of a direct connection to the alternator.
>
>
> Why isn't the other pump connected direct to the battery so that if the
> alternator fails you can switch off the buss run one pump off the battery?
>
>
> (My EFIS has a back up battery and I carry a hand held so I can operate
> with the buss off.)
>
>
> thanks
>
>
> Will
>
>
> William Daniell
>
> LONGPORT
>
> +57 310 295 0744
>
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