The Effects of Angle-of-Attack Indication on Aircraft Control in the Event of an Airspeed Indicator

102 Pages·2017·3.38 MB·English

by  Claas Tido Boesser

Dissertations and Theses
7-2013
TThhee EEffffeeccttss ooff AAnnggllee--ooff--AAttttaacckk IInnddiiccaattiioonn oonn AAiirrccrraafftt CCoonnttrrooll iinn tthhee
EEvveenntt ooff aann AAiirrssppeeeedd IInnddiiccaattoorr MMaallffuunnccttiioonn
Claas Tido Boesser
Embry-Riddle Aeronautical University - Daytona Beach
Follow this and additional works at: https://commons.erau.edu/edt
Part of the Aerospace Engineering Commons, and the Aviation Commons
SScchhoollaarrllyy CCoommmmoonnss CCiittaattiioonn
Boesser, Claas Tido, "The Effects of Angle-of-Attack Indication on Aircraft Control in the Event of an
Airspeed Indicator Malfunction" (2013). Dissertations and Theses. 24.
https://commons.erau.edu/edt/24
This Thesis - Open Access is brought to you for free and open access by Scholarly Commons. It has been accepted
for inclusion in Dissertations and Theses by an authorized administrator of Scholarly Commons. For more
information, please contact [email protected].
THE EFFECTS OF ANGLE-OF-ATTACK INDICATION ON AIRCRAFT CONTROL
IN THE EVENT OF AN AIRSPEED INDICATOR MALFUNCTION

by
Claas Tido Boesser
M.S., Embry-Riddle Aeronautical University Worldwide, 2011

A Thesis Submitted to the College of Arts and Sciences
in Partial Fulfillment of the Requirements for the Degree of
Master of Science in Human Factors and Systems

Embry-Riddle Aeronautical University
Daytona Beach, FL
Jul, 2013

ABSTRACT
Researcher: Claas Tido Boesser
Title: THE EFFECTS OF ANGLE-OF-ATTACK INDICATION ON AIRCRAFT
CONTROL IN THE EVENT OF AN AIRSPEED INDICATOR
MALFUNCTION
Institution: Embry-Riddle Aeronautical University
Degree: Master of Science in Human Factors and Systems
Year: 2013
Analysis of accident data by the Federal Aviation Administration, the National Transportation
Safety Board, and other sources show that loss of control is the leading cause of aircraft
accidents. Further evaluation of the data indicates that the majority of loss of control accidents
are caused by the aircraft stalling. In response to these data, the Federal Aviation Administration
and the General Aviation Joint Steering Committee emphasize the importance of stall and angle-
of-attack awareness during flight. The high-profile crash of Air France Flight 447, in which
pilots failed to recover from a self-induced stall, reinforced concerns over the need for improved
stall and angle-of-attack awareness and reinvigorated interest in the debate over the effectiveness
of angle-of-attack information displays. Further support for aerodynamic information in the form
of an angle-of-attack indicator comes from core cognitive engineering principles. These
principles argue for the provision of information about system functioning and dynamics as a
means to ensure a human is always in position to recover a system when technology is unable.
The purpose of this research was to empirically evaluate the importance of providing pilots with
feedback about fundamental aircraft aerodynamics, especially during non-standard situations and
unexpected disturbances. An experiment was conducted using a flight simulator to test the
ii i
effects of in-cockpit angle-of-attack indication on aircraft control following an airspeed indicator
malfunction on final approach. Participants flew a final approach with a target airspeed range of
60 to 65 knots. Once participants slowed the aircraft for final approach, the airspeed indicator
needle would be stuck at an indication of 70 knots. One group of participants flew the final
approach with an angle-of-attack indicator while the other group lacked such an instrument.
Examination of aircraft performance data along the final approach showed that, when confronted
with a frozen airspeed indicator, pilots flying with an angle-of-attack indicator were producing
less airspeed and glideslope deviation than pilots who were flying without an angle-of-attack
indicator. Furthermore, in the absence of airspeed information, pilots with an angle-of-attack
indicator were less prone to slow the aircraft to an airspeed at which the aural stall-warning
activated. Overall, the results of this experiment provide support for making aerodynamic
information available to the pilot, thus contributing empirical results to the aviation-safety debate
over the effectiveness of angle-of-attack information displays.

iv
TABLE OF CONTENTS
Page
Abstract iii
List of Tables ix
List of Figures x
Introduction 1
Human Error and Loss of Control Accidents 1
Stall as the Leading Cause of Loss of Control 2
Air France Flight 447 3
Increase Aerodynamic Awareness by Displaying AOA to the Pilot? 5
Research Objectives 6
Hypotheses 7
Limitations and Assumptions 8
Definitions of Terms 10
List of Acronyms 11
Review of the Relevant Literature 13
Background to Aerodynamics 13
The lift equation 14
Angle of attack 14
The connection between load factor and AOA 17
The role of airspeed 20
Aerodynamic Awareness Information Accessible to the Pilot 21
v
Natural stall warning: buffet 21
Artificial stall warning and stick shaker/pusher 22
Toward Aerodynamic Awareness 23
Cognitive systems engineering 23
The joint cognitive system 24
Control theory in human performance 24
Humans give the system resilience 27
Automation failure and the effects on the JCS 28
Situation awareness 29
Decision making, goals, and performance 31
How to support ”knowing what’s going on using design 34
Ecological interface design 35
Ecological interface design and situation awareness 37
Cognitive task analysis 37
Summary 38
Methods 40
Participants 40
Apparatus 41
Experimental Design 43
Pilot Testing 44
Procedure 44
The task 45
Training 45
v i
Practice trials 46
Experimental trials 46
Data Processing 47
Airspeed and glideslope deviation 48
Results 50
Descriptive Statistics 50
Hypothesis Testing 58
Multivariate normality 59
Homogeneity of variance 59
Homogeneity of covariance matrices 60
MANOVA and follow-up results 60
Time until airspeed indicator malfunction was noticed 61
Correlation Between Flight Hours and the Dependent Variables 61
Additional Measures 63
Stall warning horn activation during flight 63
Identification of the malfunction 65
Discussion, Conclusions, and Recommendations 67
Effect Sizes, Confidence Intervals, and Possible Confounds 68
Motivational Effects 69
Misconceptions 70
Floor Effect 70
Stall Warning Findings 71
Towards the Usage of AOA for GA 71
vi i
References 73
A Permission to Conduct Research 80
B Informed Consent Form 81
C Demographics Form 82
D Feedback for Participants of Angle-of-Attack Research 83
E Experiment Script 84
F PowerPoint Slides Used for Training Participants on Angle-of-Attack 87
G Excerpt from Excel Data Generated by the Plugin for X-Plane 89

vi ii
LIST OF TABLES
Table Page
1 Summary of Upset and Loss of Control Events to Transport Airplanes 3
2 RMSE Descriptive Statistics for Airspeed Deviations 50
3 RMSE Descriptive Statistics for Glideslope Deviations 54
4 Descriptive Statistics for the Log-Transformed Data 59
5 Spearman’s Correlation Coefficient (r ) for the Relationships between Participant Flight
s
Hours and Performance Measures 63
6 Stall Warning Horn Activation in the AOA versus No-AOA Condition 64
7 Number of Stall Warning Horn Activations by Participant 65
8 Correct Identification of the Malfunction in the AOA versus No-AOA Condition 66

ix