From: dst+@cs.cmu.edu (Dave Touretzky)
Subject: engine out in a twin
Organization: School of Computer Science, Carnegie Mellon
Date: Sat, 12 Sep 1992 05:13:23 GMT


Kerry Kurasaki writes, in answer to Eric Thiele's question:

>... 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.

Although it may harm my macho-multi-driver image to do so, I respectfully
disagree.  Unless you're flying some bizarre homebuilt, *nothing* terrible
will happen to you when an engine quits, as long as you maintain airspeed.

> 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.

Although we twin drivers like to talk about our near-instantaneous reactions
to engine failure, in truth this is almost never appropriate, and it isn't
necessarily a constructive thing to talk about to non-multi pilots.  In
fact, advice like this messed me up pretty badly in my early multi days; it
made me feel like I had to DO SOMETHING RIGHT AWAY.

Engine failure procedures in a twin should be practiced like tai-chi:  the
goal is to be smooth and correct, with a clear mental picture of what the
airplane is doing, not to go through the drill with blinding speed.  In an
emergency situation, speed will come if you need it.  But if you focus on a
speedy reaction, you're setting yourself up for a fall.  For example, a prop
overspeed due to a governor failure will generate cues that cause a rushed
pilot to feather the GOOD engine.

When I practice engine-out procedures, I make a conscious effort to be SLOW
and deliberate in all my actions.  Maintain directional control; keep the
airpseed at blueline; take a breath.  Try to get the power up on both
engines, and maintain directional control and airspeed.  Take another breath.
Clean up the airplane; check the climb rate.  Take a breath.  Once things
are stabilized -- which might mean the aircraft is established in a gentle
descent -- then one can think about identifying the failed engine and
feathering the prop.  These are not urgent items.

I don't do a lot of multi instruction, but I've done some.  When I first
introduce a student to engine failures, I don't say anything about
feathering procedures.  All I want him to do is keep the plane under
control.  Step on the ball, keep the airspeed at blueline, and accept
whatever climb or descent rate that gives you.  That's it.  Fly that way for
a few minutes; get a feel for adjusting to post-engine-failure flight.  We
go through this drill a bunch of times.  Once the student can smoothly react
to a power loss, then I start introducing additional elements, like adding
power, reducing drag, etc.  But those elements are not presented as "do this
in response to an emergency." The emergency response is just "center the
ball; blueline."  Nothing more is required to keep you alive.  The
additional elements merely improve climb rate once the aircraft is stable.
If you can't climb, make a gentle forced landing.

................

I do have memorized a long engine-out checklist that I can run through 
in an emergency.  Here it is:

  step on the ball   \   the emergency part
  blueline           /

  TAKE A BREATH

  mixtures	     \
  props               >  get the power up to increase climb rate
  throttles          /

  fuel		    \
  flaps		     >   insure power; reduce drag
  gear		    /

  identify	    \
  verify	     >   secure the failed engine
  feather	    /
  idle-cutoff      /

  blueline

  raise the dead    \
  save the good      >   stabilize the aircraft
  trim              /

................

A few of these items require explanation.  "Identify" is the critical one.
It's important to be absolutely certain which engine, if any, should be shut
down.  If you step on the ball to bring it back toward the center, you are
"standing on the good engine."  Your idle foot is on the side of the bad
engine.  You can verify this by closing the throttle, but if you've had only
a partial engine failure you could make things worse by shutting that engine
down.  You can't make decisions like this unless the aircraft is well under
control, so focus on the ball and blueline first.  Then it's worth taking a
few seconds to be sure of what you want to do before feathering.

"Raise the dead" means establish a three degree bank into the good engine,
which helps reduce yaw.  This raises the dead engine side, tilting the
weight vector partially in the direction of the good engine, so you don't
need so much rudder deflection to maintain heading.  (Rudder deflection
causes drag, which you want to minimize.)

"Save the good" means reduce power on the good engine to avoid overheating
it.  On my turbocharged Seneca the good engine gets pretty hot even with
mixtures rich and cowl flaps open, because the airplane is flying
significantly slower than normal cruise.  Engine cooling is noticeably
reduced.  I cruise climb at 120 KIAS, but blueline is just 89 KIAS.

................

Well, I didn't mean to write a textbook on multi flying.  I just want to
restate my point that too many multi pilots are taught to measure their
skill in terms of how quickly they can feather an engine.  They let heading
and airspeed wander all over the place as they fiddle with throttle and prop
levers.  But the real measure of multi skill is how closely they can
maintain heading and airspeed, because those are what decay most rapidly in
an unexpected engine-out situation, and if you lose one on takeoff, loss of
control is what will kill you.

-- Dave "BeastMaster" Touretzky,  CFI-AI-and-sometimes-M