From: kerry@Ingres.COM (Kerry Kurasaki)
Subject: Single Engine Operations (long)
Reply-To: kerry@Ingres.COM (Kerry Kurasaki)
Organization: Ask Computer Systems Inc., Ingres Division, Alameda CA 94501
Date: 11 Sep 92 22:36:34 GMT

In article <1992Sep11.192834.19433@i88.isc.com> ericth@i88.isc.com (Eric Thiele) writes:
>
>What is so horribly difficult about landing a twin w/ one fan dead?  
>Is the thrust from the lone non-centerline engine what gets you at slow speed?
>Torque + high crosswinds = crash?  
>Isn't the drag from the dead engine less of a factor at lower landing speeds?
>Is the window of "single engine green arc" (was that Vmc?) flyable airspeed so 
>narrow that it's exceedingly easy to stall and maybe spin?  
>Isn't landing deadstick, once the field is made, a viable option?  
>
>Can you tell I haven't a clue?
>
To answer your question with a question:  What's so hard about flying
an airplane?  Answer:  Nothing, provided you receive the proper training.
In any airplane, a novice immediately pulls back on the yoke to arrest
the sink rate which likely results in a stall.  After you are trained,
do you realize that sometimes it is better to push than to pull.  The
example is paraphrased out of Langwiesche's "Stick and Rudder".

To answer your questions in some semblance of order:

Landing a twin with one fan dead is not the problem.  It's being able to
choose your landing site.  (OK, bad humor there.)  Light twins are not
guaranteed to climb with one engine out.  Some pilots, forgetting
their training, will pull back on the stick/yoke to attempt to gain
altitude rather than set the airspeed at Blue Line (Vyse) and accept
the loss of altitude.  They lose control which is the real cause of the
fatalities.

The panic (pucker) factor is real, which results in a narrowing of the
senses and less evaluation of the situation at hand.  In flying a twin,
many of the decisions need to be made before they occur relying on
certain 'trigger' events.  More on that below.

The drag of a windmilling propeller IS significant.  It IS important to
get the bad one feathered ASAP PROVIDED you KNOW it is NOT contributing
any useful thrust.  A propeller's inability to feather makes the flight a
no-brainer no-go decision.  I consider the feather check during the
pre-takeoff runup to be the second most important item on the checklist,
after "Controls FREE and CORRECT".

What you refer to as the "window", the difference between Red Line (Vmc)
and Blue Line (Vyse) is significant in the Seneca I fly.  A 1976 model,
calibrated in mph, Vmc is 80 mph and Vyse is 105 mph.  Again, the problem
is panic, distraction, inattention, inability to accept the situation
(losing altitude) and loss of control.  There is adequate margin, provided
you are doing something about it.

"Deadstick" landings in a twin are more difficult if you are calibrated
solely on single engine aircraft.  Twins derive a substantial portion
of their lift from the fans blowing the air over the wings.  Lose one
engine, and the increased lift from the good engine and decreased lift
from the dead engine results in a roll moment which can only be counter-
acted by rudder and banking into the good engine.  Rudder effectiveness
is dependent upon airspeed.  Lose airspeed, and the plane can roll onto
its back.  It has happened.

When you shut both engines down, you have a flying rock (not that bad
really), but the glide can be much steeper than a single.  Landing in
control, with the wings level, is always preferable to being out of
control struggling to get altitude.  Being a glider is one option that
some pilots forget.

My checklist (from memory) for taking the active is:

    1.  Runway requirements (accelerate stop/go)
    2.  Operating weight and density altitude
    3.  Engine out procedures - review
    4.  Alternatives available - Is there a schoolyard off the departure
	end I shouldn't fly into?


My memory engine securing procedure taught to me:

    Attitude - Fly the plane
    Power - Add full power, mixture, props, throttles
    Cleanup - Retract gear, flaps
    Identify - Which engine is it?  Dead foot, dead engine
    Verify - Do we have the correct engine?  Nothing should happen as
	     you retard the throttle.  OR - am I getting anything useful
	     out of the troubled engine.  If I am getting partial power,
	     maybe I'll use it if I'm in a critical phase in flight
    Feather - The engine is dead, secure it

To be ultraconservative, insert "Fly the plane" between each of the above
steps.  "Fly the plane" means fly at Blue Line (Vyse), in control.

Before you taxi onto the active, you should "cock" your engine-out
pistol.  If one engine should fail, then you "pull" the trigger and
execute the procedure.  You don't have time to think, but only to
react.  There is a fine balance here.  You must not act so fast as
to perform the procedure incorrectly, but you also don't have time
think "what do I do next?".  Act quickly and methodically.

Finally, another item not mentioned, is that, in general,  twins fly faster
and have higher stall speeds than singles.  (Let's forget Malibus, TLSs,
TBM 700s, etc. for this argument)  I don't doubt that the higher energy
on landing is a contributing factor to fatalities.

Kerry