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Airplane Flying Handbook
Transition to Multiengine Airplanes
ENGINE INOPERATIVE LOSS OF DIRECTIONAL CONTROL

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Airplane Flying Handbook

Preface

Table of Contents

Chapter 1,Introduction to Flight Training
Chapter 2,Ground Operations
Chapter 3,Basic Flight Maneuvers
Chapter 4, Slow Flight, Stalls, and Spins
Chapter 5, Takeoff and Departure Climbs
Chapter 6, Ground Reference Maneuvers
Chapter 7, Airport Traffic Patterns
Chapter 8, Approaches and Landings
Chapter 9, Performance Maneuvers
Chapter 10, Night Operations
Chapter 11,Transition to Complex Airplanes
Chapter 12, Transition to Multiengine Airplanes
Chapter 13,Transition to Tailwheel Airplanes
Chapter 14, Transition to Turbo-propeller Powered Airplanes
Chapter 15,Transition to Jet Powered Airplanes
Chapter 16,Emergency Procedures

Glossary

Index

SPIN AWARENESS
No multiengine airplane is approved for spins, and
their spin recovery characteristics are generally very
poor. It is therefore necessary to practice spin avoidance
and maintain a high awareness of situations that
can result in an inadvertent spin.

In order to spin any airplane, it must first be stalled. At
the stall, a yawing moment must be introduced. In a
multiengine airplane, the yawing moment may be
generated by rudder input or asymmetrical thrust. It
follows, then, that spin awareness be at its greatest
during Vmc demonstrations, stall practice, slow
flight, or any condition of high asymmetrical thrust,
particularly at low speed/high angle of attack. Single engine
stalls are not part of any multiengine training
curriculum.

A situation that may inadvertently degrade into a spin
entry is a simulated engine failure introduced at an
inappropriately low speed. No engine failure should
ever be introduced below safe, intentional one engine inoperative
speed (Vsse). If no Vsse is published, use
Vyse. The "necessity" of simulating engine failures
at low airspeeds is erroneous. Other than training
situations, the multiengine airplane is only operated
below Vsse for mere seconds just after lift-off or
during the last few dozen feet of altitude in preparation
for landing.

For spin avoidance when practicing engine failures,
the flight instructor should pay strict attention to the
maintenance of proper airspeed and bank angle as the
student executes the appropriate procedure. The
instructor should also be particularly alert during stall
and slow flight practice. Forward center-of-gravity
positions result in favorable stall and spin avoidance
characteristics, but do not eliminate the hazard.

When performing a Vmc demonstration, the instructor
should also be alert for any sign of an impending stall.
The student may be highly focused on the directional
control aspect of the maneuver to the extent that
impending stall indications go unnoticed. If a Vmc
demonstration cannot be accomplished under existing
conditions of density altitude, it may, for training purposes,
be done utilizing the rudder blocking technique
described in the following section.

As very few twins have ever been spin-tested (none
are required to), the recommended spin recovery
techniques are based only on the best information
available. The departure from controlled flight may
be quite abrupt and possibly disorienting. The direction
of an upright spin can be confirmed from the turn
needle or the symbolic airplane of the turn coordinator,
if necessary. Do not rely on the ball position or other
instruments.

If a spin is entered, most manufacturers recommend
immediately retarding both throttles to idle, applying
full rudder opposite the direction of rotation, and
applying full forward elevator/stabilator pressure (with
ailerons neutral). These actions should be taken as near
simultaneously as possible. The controls should then
be held in that position. Recovery, if possible, will take
considerable altitude. The longer the delay from entry
until taking corrective action, the less likely that recovery
will be successful.

ENGINE INOPERATIVE
LOSS OF DIRECTIONAL CONTROL DEMONSTRATION

An engine inoperative—loss of directional control
demonstration, often referred to as a "Vmc demonstration,"
is a required task on the practical test for a
multiengine class rating. A thorough knowledge of
the factors that affect Vmc, as well as its definition,
is essential for multiengine pilots, and as such an
essential part of that required task. Vmc is a speed
established by the manufacturer, published in the
AFM/POH, and marked on most airspeed indicators
with a red radial line. The multiengine pilot must
understand that VMC is not a fixed airspeed under all
conditions. Vmc is a fixed airspeed only for the very
specific set of circumstances under which it was
determined during aircraft certification. [Figure 12-19]

In reality, Vmc varies with a variety of factors as
outlined below. The Vmc noted in practice and
demonstration, or in actual single-engine operation,
could be less or even greater than the published
value, depending upon conditions and technique.

In aircraft certification, Vmc is the sea level calibrated
airspeed at which, when the critical engine is suddenly
made inoperative, it is possible to maintain control of
the airplane with that engine still inoperative and then
maintain straight flight at the same speed with an angle
of bank of not more than 5°.

The foregoing refers to the determination of Vmc under
"dynamic" conditions. This technique is only used by
highly experienced flight test pilots during aircraft certification.
It is never to be attempted outside of these
circumstances.

In aircraft certification, there is also a determination of
Vmc under "static," or steady-state conditions. If there
is a difference between the dynamic and static speeds,
the higher of the two is published as Vmc. The static
determination is simply the ability to maintain straight
flight at Vmc with a bank angle of not more than 5°. This
more closely resembles the Vmc demonstration required
in the practical test for a multiengine class rating.

 

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