REFLECTOR:LOP Ops

[Scott Baker]

The FADEC mixture control has an electrical toggle switch with two
positions.  There is no mixture control cable.
The "Auto" position commands Best Power, regardless of the throttle or rpm
setting.  Best Power is "defined" as 100 degree rich of peak EGT.  The
"Auto" position is a checklist item for take off and landing.
The pilot can select an Economy setting - which commands the system to
achieve 100 degrees Lean of peak EGTs.  The FADEC computers will ignore the
Economy setting when the engine is developing 70% power or greater.  In
other words, if the pilot was operating in Economy mode - made an approach
to landing, and forgot to move the mixture switch to the "Best Power"
position ... the computers would automatically leave the Economy mode and
enter the Best Power mode during a go-around (when the engine is developing
more than 70% power).
Given this "failsafe" feature to revert to Best Power whenever the engine
develops 70% power or greater, we asked Aerosance "Why not leave the mixture
switch in the Economy mode all of the time ... and let the computer over
ride to Best Power whenever it is needed?" ... the answer was ... "This is
just the way we do it."
So, the pilot has some say in the mixture - but no say in setting the
increments.  In other words, it's 100 degrees lean of peak (or 100 degrees
rich of peak) and that's it.
Scott B.

----- Original Message ----- 
From: "Scott" <scott@tnstaafl.net>
To: <reflector@tvbf.org>
Sent: Thursday, December 18, 2003 7:21 PM
Subject: Re: REFLECTOR:LOP Ops


> I think you said it had two autoselections.
>
> Can you manually set it?
>
> Scott
>
> At 05:00 PM 12/18/2003, you wrote:
>
> > > >Economy mode (69% power or below), the FADEC system meters the
fuel-air
> > > >mixture to obtain 100 degrees Lean of peak.
> > >
> > > This is great news.  I assume you can set it to run at other settings?
> >100
> > > LOP will not offer the power that 50 LOP will, and 50 LOP is a nice
> >overall
> > > place for teh engine.
> >
> >Answer:    Nope.  The FADEC system has a simple "up-down" toggle switch
to
> >select the mixture mode.  The pilot cannot adjust the values.
> >
> >Scott B.
> >
> >
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