FAR 23, Modifications and Flight Test

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FAR 23, Modifications and Flight Test

• Tony Morris
• Test Pilot, CAA

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• Contents
• CAA Test Pilot Who Why?
• The need for testing
• Types of modifications
• Possible effects on the aircraft
• Examples of test programmes
• The approaches to flight testing
• Pilot qualifications
• Where to find information
• Questions

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• CAA Test Pilot Position Who Why?
• Required to ensure new/modified aircraft properly
  tested
• RAAF for 13 years
• Test flying professionally since 1990
• Graduate of the Empire Test Pilots School (UK)
• Senior Fixed-Wing Test Pilot RAAF
• Civil test pilot since 1995
• CAA Test Pilot since 2001
• 125 types
• 10,200 flying hours

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• Why do we need to test this modification?
• Legally required by legislation
• Need approval to sell commercially
• Need to define new or modified parameters
• Need to define new or changed performance

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• Types of aircraft modifications
• External
• Internal
• Powerplant

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• Possible effects on the aircraft
• Handling qualities
• Systems
• Performance

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• Handling Qualities
• (How the aircraft flies)
• We need to test if any of the following have
  changed
• Stall speed or characteristics
• Lateral/Directional (modified stability IFR?)
• Longitudinal (trim, control, damping)
• Minimum control speed (multi-engine)
• Takeoff and landing

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• Systems Modifications
• We may need to test if any of the following are
  modified
• Powerplant
• Controls
• Displays
• Pilot Interface
• Lighting
• Cockpit Space and Comfort
• Field-Of-View
• Pilot Workload

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• Performance Testing
• We will need to test if any of the following have
  changed
• Takeoff
• Climb
• Landing
• Balked Landing
• Inflight
• Roll rate
• Engine-Inoperative/Abnormal
• Restricted vs. Normal Category?

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• Example Flight Test Programmes
• Taken from personal test flying
• Still current in real test flying!
• Not just an office type with no real-world
  experience!

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• Cessna 182 FLIR Modification
• Takeoff and Landing handling qualities
• Stall speed verification
• Lateral and Directional stability and control
• Roll rate confirmation
• Systems tests

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• Geosurvey Pods Cresco
• Lateral/Directional handling
• Stall speed re-validation
• Roll rate and handling
• Takeoff, climb and landing performance
  re-validation

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• Powerplant Change Air Tractor 301
• Takeoff and landing performance
• Takeoff and landing handling
• Longitudinal, Lateral Directional handling
• Engine handling and in-flight restart
• Stall speed re-validation

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• Asymmetric Stores Carriage Lear 35
• Takeoff and landing handling (crosswind and trim
  limit)
• Climb performance decrement
• High-speed handling, stability and control (M
  0.78)
• Low speed handling and AoA stability
• Single-engine handling and minimum control speed
• Flutter
• Lateral/Directional handling, roll rate
• Qualified personnel?

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• Where do I find out what I need to test?
• FAR 23 Subpart B - Flight
• Flight Test Resources
• CAA we are here to help!
• FAA Regulatory Guidance Library (RGL)
• (www.faa.gov gt Regulations and policies gt RGL)
• Advisory Circulars support FAR 23
• You are not alone!
• Ask for help earlier rather than later!

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• The two approaches to flight test
• The easy way
• Ask for help, take advice, do the tests right
  first time in accordance with the regulations
• The hard way
• Dont ask, hire the wrong people, get it wrong,
  complain when CAA fails to approve your mod
  spend more money!
• Quick check is the CAA tough?
• CAA is probably the most user-friendly
  regulatory authority going around!
• Engineering support as good as it gets

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• Planning a Flight Test Programme
• Go it alone find out later?
• What can CAA offer?
• CAA Test plan review
• Flight test oversight
• CAA Flight Test witness
• Test pilot approval (where required)
• Report submission quality?
• CAA Audit?
• Required in certain cases
• Scope will depend on report, results and task
• Could range from 10 - 100

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• Getting the right test pilot
• Hire the RIGHT pilot, not just the one whos
  there
• Not every pilot or engineer can perform flight
  test
• Correct background/experience
• Disciplined, methodical, thorough
• Able to anticipate and understand FAR 23
  requirements
• Willing and able to take advice and direction
• Reliable and consistent test techniques
• Able to convert what they have seen to a
  readable, coherent format
• Interface between you and the CAA
• Audit?

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• Some Useful Advisory Circulars
• AC 23-8B Flight Test Guide for Certification of
  Part 23 Airplanes
• AC 23-14 Type Certification Basis for Conversion
  from Reciprocating Engine to Turbine-Powered Part
  23 Airplanes
• AC 23-17B Systems and Equipment Guide for
  Certification of Part 23 Airplanes and Airships
• AC 23.1309-1C Equipment, Systems, and
  Installations in Part 23 Airplanes
• AC 23.1311-1BInstallation of Electronic Display
  in Part 23 Airplanes

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• Helicopters?
• Part 27 Normal category
• Part 29 Transport category
• Associated ACs

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• FAR 23 Subpart B - Summary
• General
• Performance
• Flight Characteristics
• Controllability and Manoeuvrability
• Trim
• Stability
• Stalls
• Spinning
• Ground and Water Handling Characteristics
• Miscellaneous Flight Requirements

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• Performance
• 23.45 General.23.49 Stalling period.23.51
  Takeoff speeds.23.53 Takeoff performance.23.55
  Accelerate-stop distance.23.57 Takeoff
  path.23.59 Takeoff distance and takeoff
  run.23.61 Takeoff flight path.23.63 Climb
  general.23.65 Climb all engines
  operating.23.66 Takeoff climb one-engine
  inoperative.23.67 Climb one engine
  inoperative.23.69 Enroute climb/descent.23.71
  Glide Single-engine airplanes.23.73 Reference
  landing approach speed.23.75 Landing
  distance.23.77 Balked landing.

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• Controllability and Maneuverability
• 23.143 General.23.145 Longitudinal
  control.23.147 Directional and lateral
  control.23.149 Minimum control speed.23.151
  Acrobatic maneuvers.23.153 Control during
  landings.23.155 Elevator control forces in
  maneuvers.23.157 Rate of roll.
• Trim
• 23.161 Trim.

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• Stability
• 23.171 General.23.173 Static longitudinal
  stability.23.175 Demonstration of static
  longitudinal stability.23.177 Static directional
  and lateral stability.23.181 Dynamic stability.
• Stalls
• 23.201 Wings level stall.23.203 Turning flight
  and accelerated turning stalls.23.207 Stall
  warning.
• Spinning
• 23.221 Spinning.

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• Ground and Water Handling Characteristics
• 23.231 Longitudinal stability and
  control.23.233 Directional stability and
  control.23.235 Operation on unpaved
  surfaces.23.237 Operation on water.23.239 Spray
  characteristics.
• Miscellaneous Flight Requirements
• 23.251 Vibration and buffeting.23.253 High
  speed characteristics.

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• Questions?

But its only a MINOR modification!!!!