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PPL Book 5: Principles of Fight (1st Edition)
by Jon Williams - Thursday, 20 February 2014, 4:20 PM

Page 86: Chapter 4, Missing Question
In the questions to this chapter, Question 4 is missing, even though there is an answer to Question 4 in the Answers Section on Page 355.

This error is a case of a missing question, and the answers to the other questions to Chapter 4 remain correct. The missing Question is:

When (normally at high angles of attack) the Boundary Layer separates from the surface of an aerofoil (at the Separation Point), airflow characteristics aft of the Separation Point can best be described as:

a. unpredictable and haphazard, leading to an abrupt decrease in lift force.
b. smooth and laminar, leading to an increase in lift.
c. a turbulent Boundary Layer, leading to a slight reduction in lift.
d. smooth and laminar, creating a favourable Pressure Gradient.

The answer to the above question is: a.

Page 181: Error in Fig 9.7
The diagram at Figure 9.7 erroneously reverses the depiction of the lift and weight forces. The correct version of the diagram is given below.


Page 192: Rate of Turn
In the top "key" margin box, the text should read:

"During a Rate One turn, an aircraft changes direction at a rate of 3° per second."

Page 249:Chapter 11, Stability Questions
The correct answer to Question 21 is d. The surface which gives an aircraft directional stability is the fin.