Re: Loss of an engine

From:         "Joseph D. Mazza" <mazz+@andrew.cmu.edu>
Date:         03 Jan 95 01:40:39 
Organization: Naval Science, Carnegie Mellon, Pittsburgh, PA
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Followups:    1
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Excerpts from netnews.sci.aeronautics.airliners: 21-Dec-94 Loss of an
engine by eph72385@Rosie.UH.EDU 
> I am curious how a crew, most notably the pilots, could not
> notice the loss of an engine in flight.
>  
> Are there not sufficient warning systems for engines that
> would go off if an engine were to come off?  Somthing
> like a loss of oil pressure, unstable fuel flow, leaking
> hydraulic fluid, something?  Turbine speed?  Temperatures?
>  
> I am certainly no expert on commercial, or any aircraft
> for that matter.  I just find it extremely hard to believe
> that it would simply go unnoticed.

It depends on what you're doing.  If you're taking off, for example, you
have high power on both engines.  When one fails the power loss is
immediately noticible, as is the assymmetric thrust (the difference
between high power on one engine and no power on the other).  A lot of
rudder and more power on the good engine are needed right away to get
things under control and continue the climb out.

On the other hand, during a descent there is often very little power on
either engine (you're essentially gliding) so when one fails the
difference between idle power on one side and no power on the other is
slight.  There might be some warning like low RPM or the like, but they
could go unnoticed for awhile while tuning radios etc during an approach.

Since the windmilling prop usually keeps turning and generators etc may
stay on the line, a power loss might not be noticed until power is added
to slow the rate of descent, level off, or wave off.  Then the
assymmetric thrust is again obvious.

Hope this helps.

-----Joe