FAR 23, Modifications and Flight Test Tony Morris Test Pilot, CAA

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

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

“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

Types of aircraft modifications: External Internal Powerplant

Possible effects on the aircraft: Handling qualities Systems Performance

(How the aircraft ‘flies’) 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

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

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?

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!

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

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

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

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?

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 > Regulations and policies > RGL) Advisory Circulars support FAR 23 You are not alone! Ask for help – earlier rather than later!

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’: Don’t 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’

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%

Getting the ‘right’ test pilot Hire the RIGHT pilot, not just the one who’s 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?

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

Helicopters? Part 27 Normal category Part 29 Transport category Associated AC’s

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

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.

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.

Stability Stalls Spinning 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.

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.

Questions? “But it’s only a MINOR modification!!!!”