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Pilot's Handbook of Aeronautical Knowledge
Aeronautical Decision-Making
The Decision-Making Process

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Pilot's Handbook of Aeronautical Knowledge



Table of Contents

Chapter 1, Introduction To Flying
Chapter 2, Aircraft Structure
Chapter 3, Principles of Flight
Chapter 4, Aerodynamics of Flight
Chapter 5, Flight Controls
Chapter 6, Aircraft Systems
Chapter 7, Flight Instruments
Chapter 8, Flight Manuals and Other Documents
Chapter 9, Weight and Balance
Chapter 10, Aircraft Performance
Chapter 11, Weather Theory
Chapter 12, Aviation Weather Services
Chapter 13, Airport Operation
Chapter 14, Airspace
Chapter 15, Navigation
Chapter 16, Aeromedical Factors
Chapter 17, Aeronautical Decision Making

The OODA Loop.
Figure 17-10. The OODA Loop.

Orient, the second node of the Loop, focuses the pilot's
attention on one or more discrepancies in the flight. For
example, there is a low oil pressure reading. The pilot is
aware of this deviation and considers available options in
view of potential hazards to continued flight.

The pilot then moves to the third node, Decide, in which
he or she makes a positive determination about a specific
effect. That decision is made based on experience and
knowledge of potential results, and to take that particular
action will produce the desired result. The pilot then Acts on
that decision, making a physical input to cause the aircraft
to react in the desired fashion.

Once the loop has been completed, the pilot is once again in
the Observe position. The assessment of the resulting action
is added to the previously perceived aspects of the flight. to
further define the flight progress. The advantage of the
OODA Loop model is that it may be cumulative, as well as
having the potential of allowing for multiple progressions to
occur at any given point in the flight.

The DECIDE Model
Using the acronym "DECIDE," the six-step process DECIDE
Model is another continuous loop process that provides the
pilot with a logical way of making decisions. [Figure 17-11]
DECIDE means to Detect, Estimate, Choose a course of
action, Identify solutions, do the necessary actions, and
evaluate the effects of the actions.

First, consider a recent accident involving a Piper Apache (PA-
23). The aircraft was substantially damaged during impact
with terrain at a local airport in Alabama. The certi.cated
airline transport pilot (ATP) received minor injuries and the
certi.cated private pilot was not injured. The private pilot
was receiving a check ride from the ATP (who was also a
designated examiner) for a commercial pilot certificate with
a multi-engine rating. After performing air work at altitude,
they returned to the airport and the private pilot performed a
single-engine approach to a full stop landing. He then taxied
back for takeoff, performed a short field takeoff, and then
joined the traffic pattern to return for another landing. During
the approach for the second landing, the ATP simulated a right
engine failure by reducing power on the right engine to zero
thrust. This caused the aircraft to yaw right.

The procedure to identify the failed engine is a two-step
process. First, bring power to maximum controllable on both
engines. Because the left engine is the only engine delivering
thrust, the yaw increases to the right, which necessitates
application of additional left rudder application. The failed
engine is the side that requires no rudder pressure, in this
case the right engine. Second, having identified the failed
right engine, the procedure is to feather the right engine and
adjust power to maintain descent angle to a landing.

However, in this case the pilot feathered the left engine
because he assumed the engine failure was a left engine
failure. During twin-engine training, the left engine out
is emphasized more than the right engine because the left
engine on most light twins is the critical engine. This is due to
multi engine airplanes being subject to P-factor, as are single engine airplanes. The descending propeller blade of each
engine will produce greater thrust than the ascending blade
when the airplane is operated under power and at positive
angles of attack. The descending propeller blade of the right
engine is also a greater distance from the center of gravity,
and therefore has a longer moment arm than the descending
propeller blade of the left engine. As a result, failure of the left
engine will result in the most asymmetrical thrust (adverse
yaw) because the right engine will be providing the remaining
thrust. Many twins are designed with a counter-rotating right
engine. With this design, the degree of asymmetrical thrust
is the same with either engine inoperative. Neither engine is
more critical than the other.