Air Force Flight Test Center
War-Winning Capabilities … On Time, On Cost
Scientia est Virtus
Training for
First Flight
12 Nov 09
Mr David Vanhoy
Mr Karl Major
USAF Test Pilot School
(661) 277-3000
Approved for public release; distribution is unlimited.
AFFTC-PA No.: 09462
Integrity - Service - Excellence
1
Roadmap
• USAF TPS Course Overview
• 1st Flt Course Objectives
– PA HQ
– Model Validation
– ASE
• 1st Flight Checkride
– Purpose / Scenario
– Planning Elements
– Key Questions
• Summary
2
TPS Course Layout
J
F
M
A
M
J
J
A
S
O
N
D
PERF 700
FLYING QUALITIES
700
FLYING QUALITIES
800
PERF 800
FLYING QUALITIES
900
TEST MGMT 900
SYSTEMS 600
SY STEM S 700
GRADUATION
PERF 600
FLYING QUALITIES
600
FIELD TRIP
AN 500/CF 500
TEST MGMT 600
SYSTEMS 800
QUAL EVAL 900
3
Motivation!!!!
Who wants to be this guy????
5
Or this guy????
Video courtesy of Gary Aldrich
6
Objectives
1. List the 3 kinds of FQ testing that should be
conducted during the First Flight of an airplane
2. Describe the types of powered approach Handling
Qualities testing that should be conducted on a First
Flight
3. Describe the flight conditions at which First Flight
powered approach HQ testing should be conducted
4. Name the 3 test methods that can be used to evaluate
the Aero-Servo-Elastic stability of the landing
configuration
5. State the fundamental principle of test point selection
for First Flight Aero-Servo-Elastic testing
7
Risks & Risk Reduction
• Ground Testing
– Verified and Validated FCS
– Nearly Validated Structure
• Uncertainty in Predicted Aero
– Unavoidable
– Design for Robustness
GVT
SCT
Load Proof & Cal
FMET
Design Principles
Piloted Sim
• Uncertainty in Predicted Handling Qualities
– Simulator: Lack of Fidelity
– Incomplete Evaluations
– Biased Evaluations
8
Block Diagram of Simple Pitch
Axis Control System
Structural HIL Gnd Test
UNKNOWN
Coupling
GVT
Design &Sim
Sensitivity Studies
Structural
Coupling
HIL Gnd Test
9
Primary Objective:
LAND SAFELY!!
Secondary Obj: Don’t hit chase plane and get cool pics
10
Primary Objective:
LAND SAFELY!!
Secondary Obj: GET AWAY FROM THE GROUND
and Sample PA HQ
11
3 Kinds of FQ Testing for 1st Flights
1. Handling Qualities
–
OBJ 1
Primarily in PA Config
2. Aero Model Validation
3. ASE
Predict – Test – Validate and use the Build-up Approach
12
1. Handling Qualities
Powered Approach
Photo from vets-helping-vets.com
13
1st Flt Handling Qualities Tests
• Open Loop and Semi-Closed Loop FTTs
• Closed Loop Elevated Gain FTTs
• Closed Loop Ops Representative
OBJ 2
Photo from skyscrapercity.com
14
1st Flt Handling Qualities Tests
Open Loop and Semi-closed Loop FTTs
•
•
•
•
•
•
Static Stability  Trim Shot
LIMIT AMPLITUDE
of PILOT INPUTS
Time Delay and ASE  Raps
Dynamic Stability  3 Axis Doublets
Initial Response and Steady State Resp  Small Steps
Directional Stability and dR Control Power  Sideslips
Lateral Stability & da Control Power  Stabilized Turns &
Bank-to-bank Rolls
• “Elevated” g  Stabilized Turns
OBJ 2
• Predictability  Attitude Captures
• Higher Gain PA HQ & Throttle Response  Simulated App
& Go-Arounds
15
1st Flt Handling Qualities Tests
Closed Loop Elevated Gain FTTS
• Workload Build-up
– Increase aggressiveness to something
greater than anticipated for landing
– Tracking a Target (real or simulated)
• Longitudinal and Lateral/Directional Axis
– Tracking pitch attitude or flight path angle
or AOA
OBJ 2
16
1st Flt Handling Qualities Tests
Closed Loop Ops Representative Tasks
• There generally aren’t any
• Exceptions could be for modified a/c
versus actual 1st flights of new a/c
Do NOT make 1st landing a Closed Loop
Ops Representative task!!!!!!
17
2. Aero Model Validation
18
Types of Tests
Open Loop FTTs
•
•
•
•
•
•
Trim Shot
Raps
3-axis Doublets
Small Steps
Sideslips
Bank-to-bank Rolls
PTI for Individual Surfaces if required
19
Types of Tests
Open Loop FTTs
•
•
•
•
•
•
Trim Shot
Raps
3-axis Doublets
Small Steps
Sideslips
Bank-to-bank Rolls
PTI for Individual Surfaces if required
20
3. ASE
Servo
Aero
Flutter
Elasticity
21
Test Pt Selection for ASE Testing
• Identify the points where the stability margins
are the smallest
– If there is a chance you may reach one of these
points during approach, you need to test this at
altitude first
– If you will not get anywhere near your lowest
stability margin points on first flight, then STAY
AWAY from them
– Use Raps as appropriate to verify ASE stability
OBJ 5
22
Course Evaluation
C-12 First Flight
23
Purpose
Develop and Execute a 1st Flt Profile with Emphasis on FQ
Level of Learning
Objective
Application
- Appropriate execution of
Flying/Handling Qualities Test
Techniques
- Appropriate management of
Chase
Analysis
- Discern effectiveness of
mission conduct
Synthesis
- Develop appropriate plan for
first flight
Evaluation
- Assess test results in-flight
and post-flight
24
Scenario
C-90 King Air
Make suitable for Special Ops mission
25
Scenario
C-12 Special Ops Prototype
The Answer?
26
Assumptions
• Ground Tests and Taxi Tests
– Successfully completed
• Same engines as C-90 King Air
• Same system components, but application
new
– fuel lines different, tanks different, pump
locations different, etc
• Performance model: Flight manual
• Initial starting envelope given
27
Goal
• Effectively determine ability to land safely
– Via long, low gain straight-in approach &
landing
28
Planning Elements
•
•
•
•
How best to get away from ground?
Basic instruments confidence
How to expand the envelope?
Test point selection
– Flying / Handling Qualities
– Aero Model Validation
– Aeroelastic considerations
• Test point prioritization
• System operations
29
Mission Variables
• Potential System Failures
– Mock aircraft write-ups
– Airspeed, pressurization, flaps, DAS, etc.
• MIL-STD 1797, Flying Qualities of Piloted Vehicles
– Team Unique Compliance Checks
– Program office special interest item
30
Key Questions
• First flight objectives and priorities?
• Test point purpose?
• Best envelope expansion approach?
– How slow, what increment?
– How much sideslip, roll rate?
• Minimum maneuvers to attempt landing?
• What if something goes wrong?
• How do mitigate first landing risks?
– Configuration changes
• How much should you elevate the pilot’s gains?
– Cooper-Harper ratings
31
First Flight Summary
• Do Your Homework
– Simulation
– Thorough Ground Test
– Team Practice
Get Away from the Gnd
Eval PA HQ &
Land Safely
• Predict, Test, Validate Method + Build-up Approach
• PA Handling Qualities, Aero Model Validation, ASE
• Reduce Unknowns: Start test at Ideal Conditions
• Contingency Plans for Undesirable HQ or Failures
32
First Flight Testing
33
BACKUPS
34
It’s Just a Minor Mod……
V∞
35
Starting Envelope
Heart of the Envelope, then where?
•
•
•
•
•
•
140-160 KCAS
15,000 ft PA
½ Maximum Aileron Input
0.8G to 1.5G Load Factor
5° Sideslip
Flight Manual Limits for
A/C Systems
• Takeoff designed for 40%
flaps
OBJ 3
36
Brief Items
• Objectives
• Priorities
• A/C Status /
Mods / SI
• Go / No-Go
• Safe Envelope
• Envelope
Expansion Plan
• Predictions
• Time / Fuel Line
• Wx
• Area
Considerations
• Safety Brief
• Limits
• Terminology
• Com Plan
• Duties
• Contingency
Plans
Test Limits
• 60° Max Bank Angle
• 0.5G to 2.0G Load Factor
• Recover from stall at first indication of BUFFET
• All minimum speed maneuvers (VMCA) will be
terminated not later than first indication of stall
(horn or buffet, whichever occurs first)
• Maximum pressure altitude of 17,000 ft PA
• No High Gain Aggressive tracking in wingtip
formation
• Flight Manual Limits
– Engine Parameters, pressurization, yaw damper, etc
Questions You Should Ask
• What can go wrong?
– engines, fuel, configuration, etc.
• How are you going to minimize risk?
• What are the contingency plans?
– Include those plans (or the philosophy) in
the brief & be able to apply to your cards
• How far do you go looking for PIO??
• How do you accomplish higher gain PA
tasks?
Questions You Should Ask
• How Slow should you go?
– Vapp???
– Stall Warning??
– Stall??
• How much Sideslip should you generate?
• How far should you expand roll rate?
– How do you expand roll rate?
• Do you Evaluate Engine Out?
– Power settings / Airspeeds / Maneuvers?
Questions You Should Ask
• Do you raise the gear?? – ALL Config
Changes should be dedicated events
•
•
•
•
What tasks are best to simulate landing?
What axis is the most critical?
What do you track?
What are the desired and adequate
criteria?
• How important are Cooper-Harper
Ratings? – Don’t make the landing a C-H
Task!!!
It was Built to Specs……
42
Flying Qualities Phase
Course
FQ 600
Unaugmented
Airplane Motion
FQ 700
Flight Control
System
Testing
FQ 800
Stall, Departure,
Spin,
& Failure State
Testing
FQ 900
Handling Qualities
(HQ)
& Envelope
Expansion
Academic Topics
Labs, Sims & Checks
Reports
Equations of Motion
Trim & Stability
Parameter Estimation
C-12 Long-Stat & Lat-Dir
LJ-24 Long-Stat & Lat-Dir
T-38 Long-Stat & Lat-Dir
T-38 Dynamics
T-38 Long-Stat 5314
T-38 Long-Stat TR
T-38 Lat-Dir 5314
T-38 Lat-Dir TR
Intro to FCS
Analog & Digital FCS
Aero-Servo-Elasticity
Criteria for FCS Design
Freq Content, Aliasing,
Filters
Freq Response Estimation
Redundancy Mgmt Systems
FCS Ground Testing
Flight Test Simulators
Stall-Departure-Spin Testing
Failure State Testing
FQ & HQ Simulators
VISTA HQ Demo
LJ-24 FCS Project
VISTA HQ 5314
Glider Spin
T-38 Stall & HQ
C-12 & KC-135 Eng-Out
F-16 Departure
T-38 HQ/Stall 5314
T-38 HQ/Stall Oral PRR
Eng-Out Expanded 5314
F-16 Departure Oral PRR
FQ Testing Config &
Overview
Taxi testing
First-Flight FQ Testing
Handling Qualities
Evaluation
One-Flight FQ Evaluation
Stores Certification
Structures
F-16 limit Cycle Oscillation
KC-135 & Glider FQ
C-12 First-Flight Check
F-16 HQ
F-15 CFP & Asymmetric
Stores
AT-38 FQ Check
F-16 Structural Loads Check
43
Risks & Risk Reduction
•
•
•
•
Prepare the Aircraft
Prepare the Pilot
Plan the Envelope Expansion Profile
Plan for Emergencies
44
First Flight: Short and Cautious
• Riskiest parts
– Take-off
• Close to Ground
• No Build-up
– Landing
• Risk Reduction
–
–
–
–
–
Low Bandwidth Take-off and Landing
Good Weather
Long, Smooth Runway
Controlled Airspace
Crash and Rescue
45
Test Conditions
Heart of the Envelope, Approach Speeds
OBJ 3
2 1
3
4
46
Generic Profile
•
•
•
•
•
•
•
•
•
GET AWAY FROM THE GROUND
Heart-of-the-envelope Trim Shot
Air Data Checks
ASE if required
Open Loop PA HQ - compare to predictions
Closed Loop PA HQ - compare to predictions
Engine Checks
System Checks
Expand envelope to meet primary objective:
LAND SAFELY
• Long Straight-in approach /low gain landing
47
1st Flt Handling Qualities Tests
Open Loop and Semi-closed Loop FTTs
•
•
•
•
•
•
Trim Shot (Accel into to eval Static Stability)
Raps (Time Delay and ASE)
LIMIT AMPLITUDE
of PILOT INPUTS
3-axis Doublets (Dynamic Stability)
Small Steps (Initial Response and Steady State Resp)
Sideslips (Directional Stability and dR Control Power)
Bank-to-bank Rolls (Roll mode time constant & da
Control Power)
• Stabilized Turns (Spiral Stability and “elevated” g)
• Attitude Captures (Predictability)
• Simulated App & Go-Arounds (Higher Gain PA HQ &
Throttle Response)
OBJ 2
48
CASE STUDIES
Adam Aircraft Industries Photo
CASE STUDY:
ADAM AIRCRAFT M309
50
51
Recap
Photo from sodahead.com
Figure 28-37
53
Analytical Determination of Trim
Cm
atrim =
de
CN - CN
0
CN
de
d e trim =
de
Cm - Cm
0
Cm - Cm
a
de
- Cm - Cma
0
Cm
de
mg
qS
CN
a
a trim
de
54
Pitch Doublet Time History
= Aero Parameter
Identification
deact = -13.5
depred = -10.6
aact = 11.3
apred = 14.1
Figure 28-16
55
Flight Test Estimated vs Predicted
Stability Derivatives
Figure 28-17
56
Flight Test vs Updated Simulator
Comparison
Figure 28-27
57
Structural Coupling Ground Test Results
Min Damping for Flt Test
Figure 28-39
58
3 Methods to Evaluate ASE
• Pulse and Go (= Stick / Pedal RAP or PTI)
• Increasing Loop Gain
– If stability margin will get small near approach speed,
then need to verify margin at a higher speed (model
validation approach)
• Frequency Response (= Freq Sweep)
OBJ 4
59
Increasing Loop-Gain Method
1) Begin at Nominal Gain
2) Small, Sharp Input
3) Observe Control Surface: Stop or go to 4
4) Large, Sharp Input
5) Observe Control Surface: Stop or Increase
Gain
60
Time Histories of Elevator Input
Figure 28-40
61
Flight Test vs Predicted Damping
Figure 28-41
62
Taiwanese Indigenous Defense
Fighter (IDF)
Photo from skyscrapercity.com
63
Mission Objective
R1. Increase size of cargo bay to accommodate required payload.
R2. Correct Roll PIO problem found during high gain Special
Ops tasks.
R3. Improve directional stability margin to allow for safe
recovery following battle damage.
R4. Redesign tail to prevent parachute/static line entanglement
during low altitude jumps.
R5. Improve formation flying qualities, specifically concerning
Dutch-roll damping.
R6. Reduce rudder force required during rapid speed changes.
General Information
• C-12 Test Aircraft
– Pilot/Engineer Test Teams Assigned in Advance
– Each team given a SPO MIL-STD-of-Interest
• Chase Aircraft (C-12 or other low speed
aircraft)
– Random Crews Assigned by Scheduling
• Data
– Hand Held and DAS as available
– Test Day Only (No Standardization)
Mission Profile
• Designed by the FTE/Test Team
• The Following Profile OPTIONS are just
SUGGESTIONS
– Not a minimum list or an all inclusive list of
FTTs
• YOU find a BALANCE between safety,
envelope expansion, and program
requirements
Mission Profile Options
Ground Block Flying Qualities
Takeoff
Check Dash-1 normal procedures
Airborne pick-up /w photo
Climb
Pitch captures
Longitudinal stability
Flight Manual Schedule
Power effects
Air Data
“Cruise” Data Trim
Air Data
Long and Lat/Dir flying qualities
Configuration changes
Handling Qualities (PA and UA)
Model Validation
ASE
Mission Profile Options
(cont’d)
“Cruise” Data Approach to stall
cont.
Simulated single engine
Simulated go-around
Mil-Std Compliance
Maneuvers as required
Descent
Flight Path Stability
Fight Manual Schedule
Power effects
Landing
Stick forces
Configuration changes
Ground Block Flying Qualities
Instrumentation
• Handheld data
• Production gauges
• Whatever you want to bring
–
–
–
–
g-meter
Voice recorder
Tape Measure
Markers
• Simulated DAS
Test Conduct
• Data from all phases of flight
– Don’t focus so much on gathering handheld data that
you neglect other test conductor duties
• Use the chase/target as required
– Don’t forget potential photo uses
• Cautious, but accomplish something
– Controlled, intentional build-up
• Safe Envelope Definition
• Landing Option Breakpoints
– Land Now or Accomplish a Test Pt First?