Appendix D
Background Information on Re-engining Requirements

The re-engining of an aircraft is a complex task and requires a substantial amount of predefinition work to be successful. The program starts with defining the missions the aircraft will undertake and the goals of the re-engining program—e.g., fuel saving, correcting performance shortfalls, taming the escalation of support costs, or a combination of these or other goals. In most cases the basic requirements can be derived from the initial design specification for the aircraft, modified by taking into account current requirements and then incorporating current Air Force policy directives for the program. The document input to industry by a DoD entity will form the core from which can be derived all the requirements for a re-engining program.

Once program requirements have been dissected and outlined, a contractor typically defines how it will undertake a re-engining program. Two basic elements in preparing a response to a Request for Proposals (RFP) are the development of a Technical Requirements Document (TRD) and a Work Breakdown Structure (WBS), so that costs and schedules can be developed for the program. A typical table of contents for a re-engining program is displayed below to provide some insight into the complexity and considerations that must be addressed to re-engine an aircraft.

TYPICAL WORK BREAKDOWN STRUCTURE FOR A RE-ENGINING PROGRAM INCORPORATED INTO A TABLE OF CONTENTS FOR A TECHNICAL REQUIREMENTS DOCUMENT

1. SCOPE

2. APPLICABLE DOCUMENTS

2.1 PROGRAM DOCUMENTS

2.2 MILITARY DOCUMENTS

2.3 CONTRACTOR DOCUMENTS

2.4 FEDERAL AVIATION ADMINISTRATION DOCUMENTS

2.5 OTHER DOCUMENTS

2.6 SOCIETY OF AUTOMOTIVE ENGINEERS, INC. (SAE) DOCUMENTS



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Improving the Efficiency of Engines for Large Nonfighter Aircraft Appendix D Background Information on Re-engining Requirements The re-engining of an aircraft is a complex task and requires a substantial amount of predefinition work to be successful. The program starts with defining the missions the aircraft will undertake and the goals of the re-engining program—e.g., fuel saving, correcting performance shortfalls, taming the escalation of support costs, or a combination of these or other goals. In most cases the basic requirements can be derived from the initial design specification for the aircraft, modified by taking into account current requirements and then incorporating current Air Force policy directives for the program. The document input to industry by a DoD entity will form the core from which can be derived all the requirements for a re-engining program. Once program requirements have been dissected and outlined, a contractor typically defines how it will undertake a re-engining program. Two basic elements in preparing a response to a Request for Proposals (RFP) are the development of a Technical Requirements Document (TRD) and a Work Breakdown Structure (WBS), so that costs and schedules can be developed for the program. A typical table of contents for a re-engining program is displayed below to provide some insight into the complexity and considerations that must be addressed to re-engine an aircraft. TYPICAL WORK BREAKDOWN STRUCTURE FOR A RE-ENGINING PROGRAM INCORPORATED INTO A TABLE OF CONTENTS FOR A TECHNICAL REQUIREMENTS DOCUMENT 1. SCOPE 2. APPLICABLE DOCUMENTS 2.1 PROGRAM DOCUMENTS 2.2 MILITARY DOCUMENTS 2.3 CONTRACTOR DOCUMENTS 2.4 FEDERAL AVIATION ADMINISTRATION DOCUMENTS 2.5 OTHER DOCUMENTS 2.6 SOCIETY OF AUTOMOTIVE ENGINEERS, INC. (SAE) DOCUMENTS

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Improving the Efficiency of Engines for Large Nonfighter Aircraft 2.7 RADIO TECHNICAL COMMISSION FOR AERONAUTICS (RTCA) DOCUMENTS 2.8 AEROSPACE INDUSTRIES ASSOCIATION OF AMERICA, INC. DOCUMENTS 2.9 REFERENCE DOCUMENTS 3. TECHNICAL REQUIREMENTS 3.1 PROPULSION SYSTEM DEFINITIONS 3.1.1 Propulsion Pod System Definition 3.1.1.1 Engine (FAR Part 33 Certified) 3.1.1.2 Nacelle 3.1.1.3 Engine Mounts 3.1.1.4 Engine BuildUp (EBU) 3.1.1.5 Pylon 3.1.2 Airframe Modifications 3.1.2.1 Cockpit Modifications 3.1.2.1.1 Auto Throttle Compatibility 3.1.2.2 Avionics Modifications 3.1.2.3 Wing Modifications 3.1.3 Definition of Terms and Abbreviations Used 3.2 PERFORMANCE 3.2.1 Design Life 3.2.2 Propulsion System General Criteria and Operating Envelope 3.2.3 Propulsion System Operation Characteristics 3.2.3.1 Takeoff Thrust 3.2.3.2 Maximum Continuous Thrust 3.2.3.3 Thrust-Specific Fuel Consumption 3.2.3.4 Warm-up Time 3.2.3.5 Engine Operating Time 3.2.3.6 Noise 3.2.3.7 Emissions 3.2.3.8 Infrared Emissions 3.2.3.9 Electrical Power 3.2.3.10 Engine-Driven Hydraulic Pump 3.2.3.11 Bleed Air 3.2.3.11.1 Engine-Generated Substances 3.2.3.11.2 Ozone 3.2.3.11.3 Pneumatic System Performance 3.2.3.11.3.1 ECS Bleed Air System (EBAS) 3.2.3.11.3.1.1 Bleed Air Pressure 3.2.3.11.3.1.2 Overpressure Control and Indication 3.2.3.11.3.1.3 Bleed Air Temperature 3.2.3.11.3.1.4 Overtemperature Control and Indication 3.2.3.11.3.1.5 Bleed Flow 3.2.3.11.3.1.6 Pressure Drop 3.2.3.11.3.1.7 Stability 3.2.3.11.3.2 Wing Thermal Anti-Ice (WTAI) 3.2.3.11.3.2.1 Bleed Air Pressure 3.2.3.11.3.2.2 Bleed Air Temperature

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Improving the Efficiency of Engines for Large Nonfighter Aircraft 3.2.3.11.3.2.3 Bleed Flow 3.2.3.11.3.2.4 Temperature and Flow Exceptions 3.2.3.11.3.2.5 Low-Power Performance 3.2.3.11.3.2.6 Pressure Drop 3.2.3.12 Engine Overheat Prevention 3.2.3.13 Planned Maintenance Engineering Performance Envelope 3.3 STRUCTURAL REQUIREMENTS 3.3.1 Loads 3.3.1.1 General 3.3.1.2 Structural Design Loads 3.3.1.3 Factors of Safety 3.3.1.4 Material Strength Allowables 3.3.1.5 Repairability and Serviceability 3.3.2 Static Strength 3.3.3 Fatigue Criteria 3.3.3.1 Structural Fatigue Criteria 3.3.3.2 Acoustic Fatigue Criteria 3.3.3.3 Dynamics Criteria 3.3.3.4 Flutter Criteria 3.3.4 Slow Crack Growth 3.3.5 Containment 3.3.5.1 Engine Fan Blade Failure 3.3.5.2 Uncontrolled Rotating Machinery Failure 3.3.6 Bird Strike 3.3.7 Pneumatic Duct Rupture 3.3.7.1 Design for Duct Rupture and Ventilation 3.3.8 Weight and Center of Gravity 3.4 DESIGN AND CONSTRUCTION 3.4.1 General 3.4.2 Materials and Processes 3.4.2.1 Finishes 3.4.3 Physical Characteristics 3.4.3.1 Aerodynamic Smoothness Criteria 3.4.4 Identification Markings 3.4.5 Electromagnetic Interference (EMI), High-Intensity Radiated Field (HIRF), and Lightning Effects Protection 3.4.5.1 Electromagnetic Interference (EMI), High-Intensity Radiated Field (HIRF) Protection, and Lightning Indirect Effects Protection 3.4.5.2 Bonding, Shielding, Static Discharge and Lightning Direct Effects Protection 3.4.5.3 Lightning Protection Features 3.4.6 Interchangeability 3.5 MAJOR SYSTEM DESIGN REQUIREMENTS 3.5.1 General 3.5.2 Engine Mounting System 3.5.2.1 General 3.5.2.2 Mounting Structure

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Improving the Efficiency of Engines for Large Nonfighter Aircraft 3.5.3 Nacelle 3.5.3.1 General 3.5.3.2 Inlet Cowl 3.5.3.2.1 Cowl Doors 3.5.3.2.1.1 Hold-Open Provisions 3.5.3.2.1.2 Pressure Relief Door 3.5.3.3 Primary Exhaust Nozzle (as applicable) and Plug 3.5.3.3.1 Nozzle Area 3.5.3.4 Cooling and Ventilation 3.5.3.4.1 Integrated Drive Generator (IDG) Cooler Air 3.5.4 Aft Cowl/Thrust Reverser 3.5.4.1 Aft Cowl (as Applicable) 3.5.4.2 Thrust Reverser Design Requirements 3.5.4.2.1 Thrust Reverser Effectiveness 3.5.4.2.2 Thrust Reverser/Aircraft Compatibility 3.5.4.2.3 Safety and Reliability 3.5.4.2.4 Thrust Reverser Safety 3.5.4.2.5 Safety Structural Integrity 3.5.4.2.6 Fail-Safe and Discrete Source Damage Requirement 3.5.4.2.7 Structural Capability 3.5.4.2.8 Emergency Landing 3.5.4.2.8.1 Rejected Takeoff 3.5.4.2.8.2 Inflight Inadvertent Deployment up to 350 KCAS1 3.5.4.2.8.3 Inflight Inadvertent Deployment Above 350 KCAS 3.5.4.2.8.4 Rejected Landing 3.5.4.2.8.5 Others 3.5.4.2.9 Reliability/Safety 3.5.4.2.10 Reverser Functional Requirements 3.5.4.2.11 Ground Maintenance Operation 3.5.4.2.12 Lock Sensors 3.5.4.2.13 Safety/Fail-safe Requirements 3.5.4.2.14 Safety Analysis 3.5.5 Pylon 3.5.6 Fire Protection 3.5.6.1 Fire Prevention 3.5.6.2 Fire Detection 3.5.6.2.1 Leak Detection 3.5.6.3 Fire Containment 3.5.6.4 Fire Extinguishing 3.5.7 Subsystems 3.5.7.1 Pneumatic System (including Anti-Icing ) 3.5.7.1.1 General System Functional Requirements 3.5.7.1.1.1 System Design Requirements 3.5.7.1.1.1.1 Design 1 Knots calibrated airspeed.

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Improving the Efficiency of Engines for Large Nonfighter Aircraft 3.5.7.1.1.1.2 Endurance 3.5.7.1.1.1.3 Vibration 3.5.7.1.1.1.4 Flow Resonance 3.5.7.1.1.1.5 Pressure Drop 3.5.7.1.1.1.6 Structural Integrity 3.5.7.1.1.1.6.1 Proof Pressure 3.5.7.1.1.1.6.2 Burst Pressure 3.5.7.1.1.1.6.3 Thermal Effects 3.5.7.1.1.2 Equipment Design Requirements 3.5.7.1.1.2.1 Maximum Flow 3.5.7.1.1.2.2 Bleed Port Location 3.5.7.1.1.2.3 Bleed Air Shutoff 3.5.7.1.1.2.4 Reverse Flow 3.5.7.1.1.2.5 Duct Routing 3.5.7.1.1.2.6 Duct Surface Temperatures 3.5.7.1.1.2.7 Foreign Material Ingestion 3.5.7.1.1.2.8 Thermal Compensation 3.5.7.1.1.2.9 Mounting 3.5.7.1.1.2.10 Tubing Bends 3.5.7.1.1.2.11 Brackets 3.5.7.1.1.2.12 Controls 3.5.7.1.1.2.13 Duct Connections 3.5.7.1.1.2.14 Tube Connections 3.5.7.1.1.2.15 Flow Direction 3.5.7.1.1.2.16 Safety Wire and Stakes 3.5.7.1.1.2.17 Leakage 3.5.7.1.1.2.18 Valves 3.5.7.1.1.2.18.1 Valve Position 3.5.7.1.1.2.18.2 Valve Position Indication 3.5.7.1.1.2.18.3 Check Valves 3.5.7.1.1.2.19 Condensation 3.5.7.1.1.2.20 Filters 3.5.7.1.1.2.21 Adjustment Covers 3.5.7.1.1.2.22 Mounting Provisions 3.5.7.1.1.2.23 Test Provisions 3.5.7.1.1.2.24 Checkout Provisions 3.5.7.1.1.2.25 Welding 3.5.7.1.2 Specific System Functional Requirements 3.5.7.1.2.1 ECS Bleed Air System (EBAS) 3.5.7.1.2.2 Engine Pneumatic Start System 3.5.7.1.2.3 Wing Thermal Anti-Ice System 3.5.7.1.2.4 Engine/Nacelle Anti-icing System 3.5.7.1.2.5 Aircraft Equipment Pressurization System 3.5.7.2 Bleed Air Leak Detection System 3.5.7.2.1 System Functional Requirements 3.5.7.2.2 Functional Interface Characteristics

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Improving the Efficiency of Engines for Large Nonfighter Aircraft 3.5.7.3 Starting System 3.5.7.3.1 System Requirements 3.5.7.3.2 Functional Interface Characteristics 3.5.7.4 Hydraulic System 3.5.7.4.1 Lines and Fittings 3.5.7.4.2 Pumps 3.5.7.5 Electrical System 3.5.7.5.1 Interface Definition 3.5.7.5.1.1 Electrical Power System Interface 3.5.7.5.1.1.1 Generator Feeders 3.5.7.5.1.1.2 Engine Electrical Power 3.5.7.5.1.1.3 Generation System Signals 3.5.7.5.1.2 Electrical Signal Interface 3.5.7.5.1.3 Mechanical Drive Interface 3.5.7.5.1.4 Generator and Drive Cooling Interface 3.5.7.5.2 Performance Characteristics 3.5.7.5.2.1 AC Generating System 3.5.7.5.2.1.1 Integrated Drive Generator (IDG) 3.5.7.5.3 Electrical Connectors 3.5.7.5.4 Wiring 3.5.7.5.5 Grounding 3.5.7.5.6 Wiring Installations 3.5.7.5.6.1 Wire Routing 3.5.7.5.6.2 Electromagnetic Compatibility 3.5.7.5.7 System Interfaces 3.5.7.5.8 System Functional Requirements 3.5.7.5.9 Functional Interface Characteristics 3.5.7.6 Instrumentation 3.5.7.6.1 Engine Performance/Condition Functional Interface Characteristics 3.5.7.6.2 Engine Vibration Monitoring System (Provisions Only) 3.5.7.7 Ignition System-General 3.5.7.8 Fuel System 3.5.7.8.1 General 3.5.7.8.2 Fuels and Additives 3.5.7.8.3 Functional System Requirements 3.5.7.9 Propulsion Control System 3.5.7.9.1 Electronic Engine Control System (Option) 3.5.7.10 Engine Lubrication System 3.5.7.10.1 System Functional Requirements 3.5.7.10.2 Functional Interface Characteristics 3.6 RELIABILITY, MAINTAINABILITY, AND SAFETY 3.6.1 Reliability 3.6.2 Maintainability 3.6.3 Safety and Human Factors 3.6.3.1 Controls Separation 3.6.3.2 Hydraulic Isolation

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Improving the Efficiency of Engines for Large Nonfighter Aircraft 3.6.3.3 Dry Bay 3.6.3.4 Fuel System Isolation 3.6.4 Integrated Logistics Support 3.6.4.1 Supply Support 3.6.4.2 Support Equipment (SE) 3.6.4.3 Logistics Support Analysis 3.6.4.4 Training 3.6.4.5 Turnaround Time (TAT) 3.6.4.6 Utilization Rate 3.6.4.7 Diminishing Manufacturing Sources and Material Shortages (DMSMS) 3.6.4.8 Availability 3.6.4.9 Scheduled Maintenance 3.6.5 Flight Simulator 4. OPERATIONAL SAFETY, SUITABILITY, AND EFFECTIVENESS (OSS&E) 5. PREPARATION AND DELIVERY 5.1.1.1 General 5.1.1.2 Preservation 5.1.1.3 Packing and Handling Loads 5.1.1.4 Deliverable Configuration 6. APPENDIX I—INTERFACE CONTROL DOCUMENTS 7. APPENDIX II—SCHEMATICS 8. APPENDIX III—FATIGUE SPECTRUM