Training for First Flight 12 Nov 09

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Training for First Flight 12 Nov 09
Air Force Flight Test Center
War-Winning Capabilities On Time, On Cost
Scientia est Virtus

• Mr David Vanhoy
• Mr Karl Major
• USAF Test Pilot School
• [phone]

Approved for public release distribution is
unlimited.AFFTC-PA No. 09462
I n t e g r i t y - S e r v i c e - E x c e l
l e n c e
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Roadmap

• USAF TPS Course Overview
• 1st Flt Course Objectives
• PA HQ
• Model Validation
• ASE
• 1st Flight Checkride
• Purpose / Scenario
• Planning Elements
• Key Questions
• Summary

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TPS Course Layout
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Motivation!!!!
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Who wants to be this guy????
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Or this guy????
Video courtesy of Gary Aldrich
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Objectives

• List the 3 kinds of FQ testing that should be
  conducted during the First Flight of an airplane
• Describe the types of powered approach Handling
  Qualities testing that should be conducted on a
  First Flight
• Describe the flight conditions at which First
  Flight powered approach HQ testing should be
  conducted
• Name the 3 test methods that can be used to
  evaluate the Aero-Servo-Elastic stability of the
  landing configuration
• State the fundamental principle of test point
  selection for First Flight Aero-Servo-Elastic
  testing

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Risks Risk Reduction
GVT SCT Load Proof Cal FMET

• Ground Testing
• Verified and Validated FCS
• Nearly Validated Structure
• Uncertainty in Predicted Aero
• Unavoidable
• Design for Robustness
• Uncertainty in Predicted Handling Qualities
• Simulator Lack of Fidelity
• Incomplete Evaluations
• Biased Evaluations

Design Principles Piloted Sim
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Block Diagram of Simple Pitch Axis Control System
Structural Coupling
HIL Gnd Test
UNKNOWN
GVT
Structural Coupling
Design Sim Sensitivity Studies
HIL Gnd Test
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Primary Objective
LAND SAFELY!!
Secondary Obj Dont hit chase plane and get
cool pics
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Primary Objective
LAND SAFELY!!
Secondary Obj GET AWAY FROM THE GROUND
and Sample PA HQ
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3 Kinds of FQ Testing for 1st Flights

• Handling Qualities
• Primarily in PA Config
• 2. Aero Model Validation
• 3. ASE

OBJ 1
Predict Test Validate and use the Build-up
Approach
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• Handling Qualities
• Powered Approach

Photo from vets-helping-vets.com
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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
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1st Flt Handling Qualities Tests
Open Loop and Semi-closed Loop FTTs

• Static Stability ? Trim Shot
• 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
• Predictability ? Attitude Captures
• Higher Gain PA HQ Throttle Response ? Simulated
  App Go-Arounds

OBJ 2
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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
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1st Flt Handling Qualities Tests
Closed Loop Ops Representative Tasks

• There generally arent 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!!!!!!
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2. Aero Model Validation
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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

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Types of Tests
Open Loop FTTs

• Trim Shot
• Raps
• 3-axis Doublets
• Small Steps
• Sideslips
• Bank-to-bank Rolls

These are the same maneuvers previously shown
for open loop HQ

• PTI for Individual Surfaces if required

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3. ASE
Servo
Rigid Body Limit Cycle
Structural Coupling
Aero
Elasticity
Flutter
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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
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Course Evaluation
C-12 First Flight
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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
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Scenario
C-90 King Air
Make suitable for Special Ops mission
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Scenario
C-12 Special Ops Prototype
The Answer?
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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

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Goal

• Effectively determine ability to land safely
• Via long, low gain straight-in approach landing

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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

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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

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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 pilots gains?
• Cooper-Harper ratings

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First Flight Summary
Get Away from the Gnd Eval PA HQ Land Safely

• Do Your Homework
• Simulation
• Thorough Ground Test
• Team Practice
• 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

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First Flight Testing
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BACKUPS
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Its Just a Minor Mod
V8
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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
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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

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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

Its the crews responsibility to keep the
aircraft within the test limits
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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?

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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?

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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? Dont
  make the landing a C-H Task!!!

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It was Built to Specs
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Flying Qualities Phase
Course Academic Topics Labs, Sims Checks Reports
FQ 600 Unaugmented Airplane Motion 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
FQ 700 Flight Control System Testing 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 FQ HQ Simulators VISTA HQ Demo LJ-24 FCS Project VISTA HQ 5314
FQ 800 Stall, Departure, Spin, Failure State Testing Stall-Departure-Spin Testing Failure State Testing Glider Spin T-38 Stall HQ C-12 KC-135 Eng-Out F-16 Departure T-38 HQ/Stall 5314T-38 HQ/Stall Oral PRR Eng-Out Expanded 5314 F-16 Departure Oral PRR
FQ 900 Handling Qualities (HQ) Envelope Expansion 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
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Risks Risk Reduction

• Prepare the Aircraft
• Prepare the Pilot
• Plan the Envelope Expansion Profile
• Plan for Emergencies

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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

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Test Conditions
Heart of the Envelope, Approach Speeds
OBJ 3
2 1 3 4
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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

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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)
• 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)

LIMIT AMPLITUDE of PILOT INPUTS
OBJ 2
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CASE STUDIES
Adam Aircraft Industries Photo
CASE STUDY ADAM AIRCRAFT M309
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(No Transcript)
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(No Transcript)
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Recap
Photo from sodahead.com
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• Figure 28-37

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Analytical Determination of Trim
Cmd e CN0 - CNd e Cm0 - Cmd e

• atrim

CNd e Cma - Cmd e CNa
a trim
- Cm0 - Cma
d e trim
Cmd e
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Pitch Doublet Time History
Aero Parameter Identification
deact -13.5 depred -10.6
aact 11.3 apred 14.1

• Figure 28-16

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Flight Test Estimated vs Predicted Stability
Derivatives

• Figure 28-17

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Flight Test vs Updated Simulator Comparison

• Figure 28-27

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Structural Coupling Ground Test Results
Min Damping for Flt Test

• Figure 28-39

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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
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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

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Time Histories of Elevator Input

• Figure 28-40

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Flight Test vs Predicted Damping

• Figure 28-41

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Taiwanese Indigenous Defense Fighter (IDF)
Photo from skyscrapercity.com
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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.
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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)

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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

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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

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Mission Profile Options (contd)
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
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Instrumentation

• Handheld data
• Production gauges
• Whatever you want to bring
• g-meter
• Voice recorder
• Tape Measure
• Markers
• Simulated DAS

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Test Conduct

• Data from all phases of flight
• Dont focus so much on gathering handheld data
  that you neglect other test conductor duties
• Use the chase/target as required
• Dont 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?