From: dst+@cs.cmu.edu (Dave Touretzky)
Subject: more on twin engine-out
Organization: School of Computer Science, Carnegie Mellon
Date: Sat, 12 Sep 1992 09:21:08 GMT

One reason engine failures on takeoff are so dangerous to a rusty multi
pilot is that he can't bring himself to believe that his airplane has
stopped climbing.  If an engine lets go and the pilot hauls back on the
stick while asking "what the hell was THAT???" he will eventually stall and
crash.  Even with one engine out the airplane is still making plenty of
engine noise, so it can be much harder for the multi pilot to accept that
he must lower the nose no matter what, and maintain blueline to survive.

The best defense against this is to follow Kerry's advice:  mentally prepare
yourself for an engine failure prior to each takeoff.  Think about how much
runway you'll have left in front of you at the rotation point; this may
influence when you decide to bring the gear up on takeoff.  Think about
weight, density altitude, and probable single engine performance.  Think
about where you might set the bird down if you can't get it cleaned up fast
enough to climb.  And above all, remind yourself that if the going gets
rough, stepping on the ball and holding blueline should be your first
priority.

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

To answer Eric's question about why twins are hard to land with an engine out:

Consider a normal approach in a single.  If you get low, or hit a patch of
sink, you can just shove the throttle in and claw your way back up to the
correct descent profile.  Doing this in a twin is dangerous.  Due to the
asymmetric thrust, if you shove the throttle forward briskly you can roll
the airplane close to knife-edge -- or beyond that if you're slow and have
really powerful engines.  You don't want to have to add power when you're
low and slow on an engine-out approach, but if you do have to, it must be
done gradually, while bringing in plenty of rudder to counteract the yaw
force that could result in a roll.  Also, once you get the gear and flaps
down in preparation for landing, the airplane has so much drag that even
going to full power on the good engine will not result in a climb.

Knowing this, multi pilots may be tempted to bring the airplane in hot and
high with an engine out, but they then risk running out of runway.  Also,
there is a tendency to delay putting down gear and flaps until the last
minute to minimize the risk of carrying all that drag.  But saving the gear
and flaps for short-short final is dangerous.  The airplane will feel very
strange during the approach to the runway, since it will be much cleaner
than the pilot is used to.  (Possible overshoot.)  And fiddling with gear
and flaps on short-short final adds a lot to pilot workload, which may
prevent him from attending to his airspeed and runway alignment at a
critical time.

Another source of problems for the rusty pilot is that the airplane feels
funny in a turn.  It doesn't want to turn into the good engine (you'll need
extra effort to make it do this), and turning into the dead engine feels
dangerous -- the asymmetric thrust wants to steepen the turn, and you must
be sure you have enough control authority to prevent that.  Turns are best
made cautiously with an engine out, and the pilot should be sure to leave
himself room for maneuvering in the pattern.

Now you might ask if it would pay to just close both throttles on downwind;
could this be any worse than an engine-out landing in a single?  Well, as
Kerry explained, it is worse.   Most singles have pretty low approach
speeds.  In a 152 you'd be approaching at 60-65 knots with maybe a 500 fpm
descent rate.  In a Seneca you'd be doing it at 90-100 knots with probably a
1000 fpm descent rate.  In a 310 those numbers are even higher.  Things
happen faster in a twin, you'll need a lot more energy to arrest the
descent, and the energy margins are much smaller.

The right way to make an engine-out landing in a twin is to keep things as
close as possible to what you're familiar with.  Airspeed no more than 10
knots above the normal approach speed.  Do use flaps on downwind, but delay
putting in full flaps until you have the field made.  Hold the gear until
you're on final and descending smoothly to the intended touchdown point, but
don't wait until short final to put it down.  As you reduce the power on the
good engine, the effect of asymmetric thrust lessens, and the touchdown
actually feels quite normal.

-- Dave Touretzky,  CFI-AIM,  Seneca N8147E (``The Beast'')