Statistical Loads Data for Cessna 172 Aircraft Using the Aircraft

96 Pages·2001·2.18 MB·English

by  Carol Capelli

DOT/FAA/AR-01/44 Statistical Loads Data for

Cessna 172 Aircraft Using the
Office of Aviation Research

Washington, D.C. 20591
Aircraft Cumulative Fatigue
System (ACFS)

August 2001

Final Report

This document is available to the U.S. public
through the National Technical Information
Service (NTIS), Springfield, Virginia 22161.

U.S. Department of Transportation
Federal Aviation Administration
NOTICE

This document is disseminated under the sponsorship of the U.S.
Department of Transportation in the interest of information exchange. The
United States Government assumes no liability for the contents or use
thereof. The United States Government does not endorse products or
manufacturers. Trade or manufacturer’s names appear herein solely
because they are considered essential to the objective of this report. This
document does not constitute FAA certification policy. Consult your local
FAA aircraft certification office as to its use.

This report is available at the Federal Aviation Administration William J.
Hughes Technical Center’s Full-Text Technical Reports page:
actlibrary.tc.faa.gov in Adobe Acrobat portable document format (PDF).
Technical Report Documentation Page
1. Report No. 2. Government Accession No. 3. Recipient’s Catalog No.

DOT/FAA/AR-01/044
4. Title and Subtitle 5. Report Date

STATISTICAL LOADS DATA FOR CESSNA 172 AIRCRAFT USING THE August 2001
AIRCRAFT CUMULATIVE FATIGUE SYSTEM (ACFS)

6. Performing Organization Code

7. Author(s) 8. Performing Organization Report No.

Dr. John A. Cicero, Frank L. Feiter, and Dr. Jamshid Mohammadi

9. Performing Organization Name and Address 10. Work Unit No. (TRAIS)

Systems & Electronics, Inc. RPD-510
190 Gordon Street

Elk Grove Village, IL 60007 11. Contract or Grant No.
DTRS-57-93-C-00172

12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered

U.S. Department of Transportation Final Report
Federal Aviation Administration

Office of Aviation Research 14. Sponsoring Agency Code
ACE-110
Washington, DC 20591
15. Supplementary Notes
This research was conducted under SBIR Phase II research program. The FAA William J. Hughes Technical Center Technical
Monitor was Mr. Thomas DeFiore.
16. Abstract

The purpose of this research and development program was to manufacture a small, lightweight, low-cost recorder for loads usage
monitoring of general aviation and commuter type aircraft to support the Federal Aviation Administration (FAA) Operational
Loads Monitoring Program.

The scope of activities performed involved the following: (1) design, development, manufacturing and test of a low-cost
Airframe Cumulative Fatigue System (ACFS), (2) installation of the ACFS into a fleet of seven Cessna 172 aircraft owned and
operated by Embry-Riddle Aeronautical University, (3) conduct aircraft usage data acquisition on seven Cessna 172 aircraft, (4)
define the effectiveness of ACFS in the data acquisition effort and any required design changes required for the ACFS, and (5)
provide the resultant processed data from the data acquisition effort in formats useful to the FAA.

Presented in this report are the description of the ACFS, the analysis and statistical summaries of the data collected from 1000
flights representing 1168 hours of Cessna 172 aircraft operational data. The end product from the data acquisition effort includes
statistical information on acceleration, speeds, altitudes, and flight duration and distance.

17. Key Words 18. Distribution Statement
Loads, Normal acceleration, Airspeed, Altitude, Pitch, roll, This document is available to the public through the National
and yaw rates, Cessna 172 airplane Technical Information Service (NTIS) Springfield, Virginia
22161.
19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of Pages 22. Price

Unclassified Unclassified 96
Form DOT F1700.7 (8-72) Reproduction of completed page authorized
PREFACE

Systems & Electronics, Inc. (SEI) prepared this report under contract from the Federal Aviation
Administration (FAA). SEI designed and developed an airframe cumulative fatigue system
(ACFS) for general aviation and commuter aircraft. Nine of these systems were delivered to
Embry-Riddle Aeronautical University (ERAU) to be installed on their fleet of Cessna 172
aircraft. To prove the effectiveness of this low-cost ACFS system, the ACFS equipped aircraft
were flown for over 1000 hours. The results of the compiled flight loads and usage data are
presented in this report.

Mr. Thomas J. Sepka, principal investigator, designed the ACFS system hardware. Dr. John A.
Cicero developed the ACFS software. Dr. Cicero, Dr. Jamshid Mohammadi, Mr. Douglas
Shoemaker, and Mr. Frank L. Feiter conducted the data analysis, data evaluation, and processing.

SEI would like to extend its appreciation to Mr. Thomas DeFiore of the FAA for the support to
this program and to Dr. David Kim of ERAU who provided help in the acquisition of the
recorded flight data.

iii/iv
TABLE OF CONTENTS

Page

EXECUTIVE SUMMARY ix
1. INTRODUCTION 1
2. AIRCRAFT DESCRIPTION 1
3. AIRCRAFT DATA COLLECTION AND EDITING SYSTEM 4
3.1 DATA COLLECTION SYSTEM 4
3.2 DATA EDITING SYSTEM 4

4. SEI DATA PROCESSING 4
4.1 RECORDED PARAMETERS 4
4.2 DERIVED AND EXTRACTED PARAMETERS 5

4.2.1 Identification of Liftoff and Touchdown 5
4.2.2 Flight Distance 5
4.2.3 Flight Duration 6
4.2.4 Design Load Factor Definition 6
4.2.5 Derived Gust Velocity 8

4.3 DATA REDUCTION 10

4.3.1 Initial Quality Screening 10
4.3.2 Time History Files 10
4.3.3 Relational Database 11

4.4 DATA REDUCTION CRITERIA 11

4.4.1 Ground/Flight Phases of Recorded Data 11
4.4.2 Sign Convention 11
4.4.3 Peak-Valley Selection 12
4.4.4 Separation of Maneuver and Gust Load Factors 12
4.4.5 Altitude Bands 12
4.4.6 Vertical Acceleration Bias Correction 14

5. DATA PRESENTATION 14
5.1 AIRCRAFT USAGE DATA 14

5.1.1 Altitude and Flight Distance Data 16
5.1.2 Coincident Airspeed and Altitude Data 17
v
5.1.3 Maximum Operating Airspeed Data 17
5.1.4 Flight Duration 17

5.2 GROUND LOADS DATA 17

5.2.1 Airspeed at Liftoff and Touchdown 18
5.2.2 Pitch Rate at Liftoff 18
5.2.3 Load Factor Data During Ground Operations 18

5.3 FLIGHT LOADS DATA 18

5.3.1 Gust Loads Data 18
5.3.2 Maneuver Loads Data 19
5.3.3 Combined Maneuver and Gust Loads Data 19

6. CONCLUSIONS AND RECOMMENDATIONS 20
7. REFERENCES 21
APPENDICES

A(cid:151)Statistical Formats, Aircraft Usage Data, All Aircraft
B(cid:151)Statistical Formats, Aircraft Usage Data, Daytona Aircraft
C(cid:151)Statistical Formats, Aircraft Usage Data, Prescott Aircraft

LIST OF FIGURES

Figure Page

1 Cessna 172 Three-View Drawing 3
2 Description of Flight Phases 11

LIST OF TABLES

Table Page

1 Cessna 172(cid:151)Characteristics 2
2 Aircraft Dimensions 3
3 Altitude Bands 13
4 Flight Distance Ranges 13
5 Statistical Formats 15
6 Flight Characteristics of Surveyed Aircraft 20
7 Operational Load Monitoring Cessna 172 21
vi
LIST OF SYMBOLS AND ABBREVIATIONS

A aircraft PSD gust response factor
A incremental load factor at operating weight (n -1)
N z
A incremental gust or maneuver design load factor at maximum gross weight (n - 1)
NLLF z
A aspect ratio b2/S
r
a speed of sound (ft/sec)
a speed of sound at sea level (ft/sec)
0
ACFS Airframe Cumulative Fatigue System
ADX Air Data Transducer
b wing span (ft)
c wing mean geometric chord (ft)
C aircraft discrete gust response factor
C wing lift curve slope per radian
lα
C maximum lift coefficient
lmax
c.g. center of gravity
D distance
ERAU Embry-Riddle Aeronautical University
F(PSD) continuous gust alleviation factor
FAA Federal Aviation Administration
fpm feet per minute
ft feet
g gravity constant, 32.17 ft/sec 2
GPS Global Positioning System
H pressure altitude (ft)
p
hrs hours
K gust alleviation factor
K discrete gust alleviation factor, 0.88 µ/(5.3 + µ)
g
KCAS knots, calibrated airspeed
KIAS knots, indicated airspeed
kts knots
L turbulence scale length (ft)
lbs pounds
m lift curve slope per radian
M Mach number
n load factor (g)
N number of occurrences for U (PSD gust procedure)
σ
nm nautical mile
n normal load factor (g)
z
N number of zero crossings per nautical mile (PSD gust procedure)
0
q dynamic pressure (lbs/ft2)
ρ air density, slugs/ft3 (at altitude)
ρ standard sea level air density 0.0023769 slugs/ft3
0
S wing area (ft2)
SEI Systems & Electronics, Inc.
vii
( )
2W / S
µ airplane mass ratio,
ρgcC
lα
U derived gust velocity (ft/sec, equivalent airspeed)
de
U continuous turbulence gust intensity (ft/sec, true airspeed)
σ
V design speed for maximum gust
B
V design cruise speed
C
V calibrated airspeed
CAS
V design dive speed
D
V equivalent airspeed
e
V indicated airspeed
I
V maximum allowable operating airspeed
NE
V true airspeed
T
W gross weight (lbs)

viii
EXECUTIVE SUMMARY

Systems & Electronics, Inc. (SEI) under Contract DTRS-57-93-C-00172 to the Federal Aviation
Administration (FAA), which was Phase II of a Small Business Innovation Development Phase I
initiative, conducted research and development as presented herein. The purpose of this research
and development program was to manufacture a small, lightweight, low-cost recorder for loads
monitoring of general aviation and commuter type aircraft to support the FAA Operational Loads
Monitoring Program. The scope of activities performed involved the following:

1. Design, development, manufacturing, and test of a low-cost Airframe Cumulative Fatigue
System (ACFS),
2. Installation of the ACFS into a fleet of seven Cessna 172 aircraft owned and operated by
Embry-Riddle Aeronautical University (ERAU),
3. Conduct aircraft usage data acquisition on seven Cessna 172 aircraft,
4. Define the effectiveness of ACFS in the data acquisition effort and any required design
changes required for the ACFS, and
5. Provide the resultant processed data from the data acquisition effort in formats useful to
the FAA.

Presented in this report are the description of the ACFS, the analysis and statistical summaries of
the data collected from 1000 flights representing 1168 hours of Cessna 172 aircraft operational
data. The end product from the data acquisition effort includes statistical information on
acceleration, speeds, altitudes, and flight duration and distance.

ix/x
1. INTRODUCTION.
Systems & Electronics, Inc. (SEI) completed Phase II of a Federal Aviation Administration
(FAA) sponsored Small Business Innovative Research (SBIR) initiative. This report includes a
summary of the design, development, manufacturing, and test of a low-cost Airframe
Cumulative Fatigue System (ACFS). This report also includes the results of the operational
flight and ground load data survey. This report presents acquired, processed, and evaluated
statistical flight load data from the Cessna 172 aircraft.

The main objectives of this program were:

• To design, develop, manufacture, and test a low-cost ACFS.

• To use the ACFS to acquire, evaluate, and utilize typical operational in-service data,
which can be used in structural fatigue damage reliability analysis of the aircraft.

• To provide a basis to assess the structural condition of the aircraft in an attempt to
evaluate any future improvement that may be necessary for the aircraft design.

This phase of the program involved the acquisition and analysis of operational flight and ground
load data using the ACFS. The ACFS was installed on a fleet of seven Cessna 172 aircraft. SEI
performed all the relevant tasks associated with data compilation, analysis, editing, and
preparation of statistical flight load data results.

This report is prepared in accordance with the format provided by the FAA and includes the
statistical loads derived from recorded data obtained from seven aircraft. There were a total of
about 1000 flights and about 1168 hours of operation. This report contains a brief description of
the Cessna 172 aircraft followed by the processes used for data collection, editing, and
processing. The statistical formats and aircraft flight usage data in the form of graphs are
presented in the appendices.

2. AIRCRAFT DESCRIPTION.
The Cessna 172 is a single engine aircraft with a maximum cruise speed at altitude of 122 knots
and a maximum range of about 580-687 nautical miles (nm). Table 1 summarizes certain
operational characteristics of the Cessna 172 aircraft equipped with SEI(cid:146)s airframe cumulative
fatigue system. An overall view drawing of the aircraft is shown in figure 1, and the aircraft
overall dimensions are presented in table 2.

1