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From: "rijakits" <rijakits@cwpanama.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-769952@logan.com>
Subject: Re: [FlyRotary] Re: fuel cutoff valve necessary?
Date: Fri, 4 Mar 2005 22:38:32 -0500
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----- Original Message ----- 
From: "Ernest Christley" <echristl@cisco.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Friday, March 04, 2005 10:11 AM
Subject: [FlyRotary] Re: fuel cutoff valve necessary?


> rijakits wrote:
>
> >     If you get distracted and fumble around in an emergency for the
> >     fuel shut off you are way behind on your emergency procedure
> >     practise anyway! That should be one of those items in your flying
> >     career that should go automatic even if you are in a coma!
> >
> >     If you don't use the fuel shut off regularly you still should be
> >     able to get at it and actuate it blind/sleeping/dumbfounded/etc.!!
> >
> Extra training is NOT and will NEVER be an answer to poor ergonomic
> system design.
>
> Adding valves and switches should only happen if they actually increase
> safety, not to guard against a possible 'something might happen'.  If
> there is a benefit to a pilot controlled shutoff valve (vs. the mechanic
> controlled one) that is not obtained by cutting the power to the pump,
> then I'm all ears.  Otherwise, it appears that a cutoff valve is an
> additional piece of complexity that reduces safety by introducing
> additional failure modes and becoming a distraction (albeit, a small
> one) in an emergency.
>
> "You should be able to do *XXX* while in a coma" is obviated by "there
> is no *XXX* to do".

Excuse me, but there you are wrong!
Didn't you prefer to have the ON/OFF switch from the fuel pump as the sole
means to shut off the fuel?
So you still have to switch that switch (the "XXX" in a coma is still
there!) - However that switch will probably brake at some stage as you most
likely use it at least twice every flight.
Now it freezes open or the switchlever brakes, how do you shut off the fuel
(incl. the fuel flow) without pulling the Masterswitch or -fuse?
I am not reaching here either - I had both things happen (clutch engagement
switch lever broke in the engaged position, no problem as my next stop was
on base anyway, but it was a broken switch) on a different occasion the
internals of the same switch in a different helicopter would freeze although
the lever was moveable - (looked like a little corrosion worked well and a
coulple of sparks did the rest).
I will take a couple of photos tomorrow of these switches and the fuel shut
off, which is a very simple off the shelf affair (no need for one off
production!) - we are talking EMERGENCY shut off, NOT fuel selector for
various tanks. You put this thing in the system where all lines are already
united into one single feeder. You probably never wear this valve out
either - you only will check it once in a while, but at least at your
personal anual or if you want to drain the tanks. I admit in the Robinson
helicopters things are simple as there is a gravity feed, at least in the
old models ( the newer is fuel injected and has an electric fuelpump in
addition to the engine driven one...) and the tanks are permanently cross
fed.

In an emergency there is only two things to do: fuel and electricity as Paul
mentioned.
Fuel gets really important if you on fire! Now what if that fire already ate
some of your electrics?
Thanks but I will go "mechanical" with a simple valve - I take my chances
with 2 additional fueline connections!

Thomas J. :))