EPFD_02_02_SRD-DRAFT-REV A-20201130.pdf

EPFD-02-02

Uncontrolled when printed. The electronic version is the official approved document.

National Aeronautics and Space Administration

Electrified Powertrain Flight Demonstration (EPFD) Project

System Requirements Document (SRD)

Date: November 24, 2020

EPFD System Requirements Document (SRD) Document No: EPFD-02-02 Revision:

Effective Date: Page ii

Prepared by:

Name Date Signature

Steven R. Jacobson

EPFD Lead System Engineer

Concurred by:

Adabelle Narvaez-Legeza

EPFD Chief Engineer

Approved by:

Gaudy M Bezos-O'Connor EPFD Project Manager

Effective Date: Page iii

Document Revision Log

Status Revision Change Request

Effective Date Description Affected

Location N/A 08/31/2020 Baseline 11/25/2020 Updated numerous requirements

Effective Date: Page iv

TABLE OF CONTENTS

1.0 INTRODUCTION

1.1 Purpose

1.2 Scope

1.3 Applicability

1.4 Change Authority and Responsibility

2.0 RELATED DOCUMENTATION

2.1 Applicable Documents

2.2 Reference Documents

3.0 SYSTEM DESCRIPTION

3.1 Ground Tests and Demonstration

3.2 EPFD Flight Demonstration

3.3 Requirements Trace

3.4 Verification of NASA driving requirements and system requirements

4.0 EPFD SYSTEM REQUIREMENTS

4.1 Requirements that Primarily Support Driving Requirement 1

SRD-01 - EPFD Transport Mission Types

SRD-02 - Flight Test Environment

SRD-03 - Data Rights

4.2 Requirements that Primarily Support Driving Requirement 2

SRD-04 - Flight Test Demonstration of high voltage Integrated MW-class powertrain systems

SRD-05 - Flight Test Demonstration of high power Integrated MW-class powertrain systems

SRD-06 – Electromagnetic Interference (EMI) and Electromagnetic Compatibility

(EMC) 12

SRD-07 – Demonstrate an Energy Storage System

SRD-08 - EPFD Propulsion during Flight Phases

4.3 Requirements that Primarily Support Driving Requirement 3

SRD-09 - EPFD Crewed Flight Testing

SRD-10 - Airworthiness and Flight Safety Review Process

SRD-11 – Industry Partner Proposed Airworthiness Process

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SRD-12 - Environmental Testing

SRD-13 - Structural Airworthiness Requirements

SRD-14 – Software Requirements

4.4 Requirements that Primarily Support Driving Requirement 4

SRD-15 - First Flight No Later Than Date

4.5 Requirements that Primarily Support Driving Requirement 5

SRD-16 - Thermal Management System

SRD-17 - Hot Day Operations

4.6 Requirements that Primarily Support Driving Requirement 6

SRD-18 - Fault Control System

4.7 Requirements that Primarily Support Driving Requirement 7

SRD-19 - Obtain Integrated MW-class Powertrain Test Data In-Flight

SRD-20 - Removed

SRD-21 - Engineering Units

4.8 Requirements that Primarily Support Driving Requirement 8

SRD-22 – Identify & Develop Standards Identified In Regulations and Standards Gap Analysis

SRD-23 - Dissemination of MW-Class Powertrain data

4.9 Requirements that Primarily Support Driving Requirement 9

SRD-24 - Obtain Integrated MW-Class Powertrain Ground Test Data

SRD-25 - EPFD Ground Testing

SRD-26 - Pre/Post System Performance Model Data

APPENDIX A EPFD PROJECT NEEDS, GOALS AND OBJECTIVES

A.1 EPFD Project Need

A.2 EPFD Project Goals

A.3 EPFD Project Objectives

APPENDIX B EPFD VERIFICATION MATRIX

APPENDIX C EPFD TRACEABILITY MATRIX

APPENDIX D EPFD ALLOCATION MATRIX

APPENDIX E ACRONYMS

APPENDIX F TO BE DETERMINED AND TO BE RESOLVED ITEMS

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List of Figures

Figure 1 - EPFD Project Internal Requirements Flow Figure 2 - Industry Requirements Flow In Response to NASA EPFD Requirements

List of Tables

Table 1 - ARMD Strategic Thrust 3 and Critical Commitment 3.1 Table 2 - List of Applicable Documents Table 3 - List of Reference Documents Table 4 - Driving Requirements Table 5 - ARMD Needs from NASA Critical Commitment Table 6 -SRD Verification Matrix Table 7 - EPFD Verification Methods Table 8 - EPFD Traceability Matrix Table 9 - EPFD Allocation Matrix Table 10 - List of Acronyms Table 11 - To Be Determined Items Table 12 - To Be Resolved Items file://Users/srjacobs/Documents/Projects/EPFD/EPFD%20Systems%20Engineering/EAP%20system%20requirements/EPFD_02_02_SRD_REV4.docx#_Toc57191574

Document No: EPFD-02-02-SRD Revision:

Effective Date: Page 1

1.0 INTRODUCTION

The purpose of Electric Powertrain Flight Demonstration (EPFD) Project is to reduce the risk of commercial application associated with Electrified Aircraft Propulsion (EAP) powertrains and components. In partnership with US Industry, an integrated megawatt (MW) class powertrain system will be designed, built, integrated, and ground and flight tested. This document will provide the overall guidance for the planning and formulation activities of the Project.

NASA’s Aeronautics Research Mission Directorate (ARMD) strategy has identified Six Strategic Thrusts in response to Three Global Aviation Mega-Drivers that will, in large part, shape the needs of aeronautical research in the coming years. These drivers and thrusts are described in the ARMD Strategic Implementation Plan (SIP) (http://www.aeronautics.nasa.gov/strategic-plan.htm).

Associated with the Strategic Thrusts (ST) are Critical Commitments (CC) which are ARMDs major planned and funded contributions to the achievement of the STs and their associated Outcomes. The CCs articulate the commitment to the aviation community, the Agency, and Congressional stakeholders. Strategic Thrust 3 and its associated CC (3.1) can be seen in Table 1.

Table 1 - ARMD Strategic Thrust 3 and Critical Commitment 3.1 Strategic Thrust Critical Commitment 3 Ultra-Efficient Subsonic Transports:

Realize revolutionary improvements in economics and environmental performance for subsonic transports with opportunities to alternative propulsion and energy.

3.1 Demonstrate practical vehicle-level

integration of MW-class electrified aircraft propulsion systems, leveraging advanced airframe systems to reinvigorate the regional and emerging smaller aircraft markets and strengthen the single aisle aircraft market.

In support of the NASA Strategic Thrust 3, Electrified Aircraft Propulsion research and development is rapidly gaining momentum as integrated compounding benefits of electrified aircraft propulsion technology are uncovered. Electrified aircraft propulsion technology shows promise with the potential to provide significant benefits in terms of fuel consumption and emissions. Such advances could pave the way for more cost-effective commercial aviation, while also reducing adverse societal impacts.

With the Electrified Powertrain Flight Demonstration Project, NASA will:

- Flight demonstrate integrated, MW-class electric drive train, power distribution, and energy storage systems with US Industry participation

- Identify and address barrier technical and integration risks and regulations and standards gaps associated with such systems

In doing so, EPFD will make direct and measurable progress toward accomplishment of ST 3 and CC 3.1.

http://www.aeronautics.nasa.gov/strategic-plan.htm

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1.1 Purpose

The purpose of this document is to describe the system-level requirements for the EPFD project for development of integrated MW-class powertrain technologies. The EPFD System Requirements Documents is a companion document to the EPFD Statement of Objectives (SOO). In the SOO, the EPFD project is stating why the data we are asking for is important to NASA, and how the SOO meets NASA ARMD’s Critical Commitment to accelerate MW Class Powertrains to the aviation commercial market.

The EPFD project will share this Systems Requirements Document with the industry partners so they can understand the criteria NASA is using, internal to the Project, to assess/verify whether the contractor provided SRD, and subsequent data that are being provided, meets NASA’s objectives in the SOO, and ARMD’s Critical Commitment.

1.2 Scope

The scope of this document covers the system-level requirements of the EPFD project ground and flight demonstrations of integrated MW-class powertrain systems and technologies. The nature of the project is such that the details of the system, including functions, interfaces and operations will be proposed by an Industry Partner. The EPFD system-level requirements trace to the EPFD project goals and objectives, SOO, standards, airworthiness and technical data.

The EPFD system-level requirements link NASA and Community stakeholder needs to the project’s goals and objectives.

The terms “shall,” “will,” and "should” are used with specific intent throughout this document and are defined as follows:

• "Shall": Used indicate a binding and require formal verification.

• "Will": Used to indicate a statement of fact or express intent, are non-binding, and therefore do not require formal verification.

• "Should": Used to indicate a desired goal and does not require formal verification.

1.3 Applicability

The requirements in this document are applicable to the EPFD project and the Industry Partners. These requirements are applicable for the entire project lifecycle including demonstrations during the EPFD project. They are not specifically applicable to the vision vehicle as its capabilities will likely exceed the requirements in this SRD. The Industry Partner shall supply a System Requirements Document (DRD SE-06) and an aircraft system description (DRD SE-03) that is responsive to the Driving Requirements (DR) and System Requirements in this document. These Industry Partner documents shall be representative of the requirements and features that are appropriate for their integrated MW-class powertrain system and trace to this SRD.

1.4 Change Authority and Responsibility

This document will follow the EPFD Configuration and Data Management Plan (EPFD-01-04).

Any changes after baseline will go through a Configuration Control Board review and an approval process.

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2.0 RELATED DOCUMENTATION

This section lists additional, related documents. Section 2.1 lists the applicable documents.

Section 2.2 lists recommended reference documents for information purposes.

2.1 Applicable Documents

Table 2 lists documents that are specifically called out in this document. The following documents include specifications, models, standards, regulations, guidelines, handbooks, and other special publications. The documents listed in this section are applicable to the extent specified herein.

Table 2 - List of Applicable Documents

Document Number Document Title

NPR 7123.1C NASA Systems Engineering Processes and Requirements

AFOP-7900.3-023,

Revision G

Airworthiness and flight safety review process (NASA Armstrong Flight Research Center [AFRC] document)

AFG-7123.1-001 Aircraft Structural Safety of Flight Guidelines NPR 7900.3D NASA Aircraft Operations Management

RTCA DO-160 Environmental Conditions and Test Procedures for Airborne Equipment

RTCA DO-178C Software Considerations in Airborne System and Equipment Certification

AFOP-7900.3-004 Environmental Acceptance Testing: Electronic & Electromechanical Equipment (NASA AFRC document)

NASA TM X-64970 Hot, Cold, And Annual Reference Atmospheres For Edwards Air Force Base (EAFB), California (1975 Version)

14 Code of Federal Regulations (CFR) 23

Airworthiness Standards: Normal Category Aircraft

14 CFR 25 Airworthiness Standards: Transport Category Airplanes 14 CFR 33 Airworthiness Standards: Aircraft Engines 14 CFR 35 Airworthiness Standards: Propellers EPFD 02-06 EPFD Technical Measures of Effectiveness

EPFD 02-04 EPFD Concept of Operations EPFD SOO EPFD Statement of Objectives

SAE AS210 Definition of Commonly Used Day Types (Atmospheric Ambient Temperature Characteristics Versus Pressure Altitude)

Effective Date: Page 4

2.2 Reference Documents

Table 3 list documents that contain supplemental information to guide the user in the application of this document. The following documents include specifications, models, standards, guidelines, handbooks, and other special publications. The documents listed in this section are applicable to the extent specified herein.

Table 3 - List of Reference Documents

Document Number Document Title

EPFD-01-18-PLR (TBD-

06)

Program Level Requirements (PLR)

EPFD-02-01-SEMP

(TBD-06)

Systems Engineering Management Plan (SEMP)

EPFD-01-01-PMP (TBD-

06)

Project Management Plan (PMP)

EPFD-01-05-TDP Technology Development Plan (TDP)

EPFD-01-10-NGO & DR

(TBD-06)

Project Needs, Goals, Objectives (NGO) and Driving Requirements (DR)

AFOP-7900.3-022 Tech Brief and Mini-Tech Brief EPFD-01-22 Data and Intellectual Property Management Plan MIL-HDBK-310 Global Climatic Data For Developing Military Products

3.0 SYSTEM DESCRIPTION

The EPFD project procurement strategy is to contract with industry to mature integrated MW-class powertrain system technology, integrate a MW-class powertrain onto an aircraft for flight demonstrations, and conduct ground and flight testing to meet the stakeholder’s expectations. Due to the procurement strategy, there is no formal NASA system architecture, the system architecture is “owned” by the Industry Partners(s).

3.1 Ground Tests and Demonstration

The EPFD Industry Partner will conduct ground tests and demonstrations of integrated MW-class powertrain system components and integrated systems to mature technology prior to flight demonstrations. It is anticipated that ground demonstrations will occur at Industry Partner’s facilities or NASA’s facilities. Ground demonstrations should be carried out by Industry Partners in appropriate test facilities, per their approach and schedule, to meet requirements and incrementally demonstrate MW-class powertrain components and technology capabilities.

3.2 EPFD Flight Demonstration

The EPFD project intends to award contracts for at least two flight demonstrations to mature integrated MW-class powertrain system technology. The EPFD integrated MW-class powertrain system flight test aircraft will be Industry owned and operated. The integrated

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MW-class powertrain system will fly at altitudes and speeds representative of commercial aviation routes.

The EPFD integrated MW-class powertrain system testbed aircraft will be integrated with a MW-class electrified propulsion system which consists of subsystems that convert electrical power to aerodynamic thrust. The powertrain system will be integrated with existing primary propulsion system(s) and flying test aircraft. EPFD subsystems will include MW-class motors/generators, power transmission, thermal management, control system, inverters/converters, batteries and turbomachinery. The EPFD testbed can use Integrated MW-class powertrain systems during any phase of ground and flight operations where these systems are required for the Vision Vehicle.

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3.3 Requirements Trace.

The requirements trace up to the EPFD project Needs, Goals, and Objectives which are found in EPFD-01-10 and are referenced in Appendix A. A number of Driving Requirements have been identified. Driving Requirements are stated in EPFD-01-10 and listed below along with the verification method that will be used by NASA to verify each requirement.

Table 4 - Driving Requirements

Driving Requirement NASA Verification Method

DR 1: The EPFD integrated MW-class powertrain system ground and flight demonstration(s) shall reduce barrier technical risks associated with the system to enable U.S.

industry to be first to market with an EAP based Vision Vehicle Product.

Analysis

DR 2: The EPFD integrated MW-class powertrain system flight demonstration(s) shall demonstrate in flight high voltage operation at all relevant ground and flight conditions.

Analysis

DR 3: The EPFD integrated MW-class powertrain system flight demonstration(s) shall conduct crewed (human rated) flight operations and testing.

Inspection

DR 4: The EPFD integrated MW-class powertrain system flight demonstration(s) shall conduct first flight no later than 2023 if feasible and no later than March of 2024. Spiral developments may extend into 2025.

Inspection

DR 5: The EPFD integrated MW-class powertrain system flight demonstration(s) shall demonstrate in flight a thermal management system for the electrical power system.

Analysis

DR 6: The EPFD integrated MW-class powertrain system flight demonstration(s) shall demonstrate in flight a control system which manages electrical faults while maintaining fail-safe aircraft operations.

Analysis

DR 7: The EPFD integrated MW-class powertrain system flight demonstration(s) shall measure the performance of the system against the technical performance metrics (TPMs)

– Reference EPFD 02-06 Table 7 for TPMs.

Analysis

DR 8: The EPFD integrated MW-class powertrain system flight demonstration(s) shall provide ground and flight test data to address gaps in regulations and standards associated with deployment of the integrated MW-class powertrain on the EAP Vision Vehicle.

Analysis

DR 9: The EPFD integrated MW-class powertrain system flight demonstration(s) shall acquire ground and flight data used to validate NASA modeling tools and research.

Analysis

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The EPFD requirements flowdown is seen below in Figure 1. The EPFD project needs, goals and objectives are referenced in Appendix A.

Figure 1 - EPFD Project Internal Requirements Flow

Additional detail for some of the requirements in the EPFD Systems Requirements Document are provided in the Data Requirements Deliverables (DRDs) and the Request for Proposal

(RFP).

Figure 2 Illustrates how the Industry partner will develop their statement of work and proposal response based on NASA’s Statement of Objectives (SOO), EPFD Systems Requirements Document, DRDs and RFP.

Program

Project

Mission

Integrated Aviation Systems Program (IASP)

Aeronautics Research Mission Directorate

Concept of Operations

EPFD System Requirements Document

Airworthiness

Driving Requirements

EPFD

Needs Goals and

DRDs, RFP

Statement of Objectives (SOO)

Technical Measures of Effectiveness

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Figure 2 - Industry Requirements Flow In Response to NASA EPFD Requirements

Statement of Objectives (SOO)

Describes: Project background, and the project management, contract management and technical objectives Industry

Develops: SOW and SRD specifying how their demo is responsive to the

SOO, EPFD SRD,

DRDs and how technology will transition to product

Source Evaluation Board: Evaluates proposal against selection criteria

Final Contract(s) Awarded

Data Requirement Description (DRD) Data needs for PM, PP&C, Eng, S&MA

(i.e. MML, Tech Data/Plan(s))

System Requirements

Document (SRD) System level requirements derived from NGOs and DRs

RFP/Draft Contract

NASA SOO combined with an Industry provided SOW allows efficiency and flexibility for Industry to be responsive to NASA’s requirements

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Many of the system requirements reference the Technical Performance Metrics which can be found in EPFD-02-06.

3.4 Verification of NASA driving requirements and system requirements The NASA EPFD team will verify the driving requirements and system requirement using analysis and inspection methods from data that are produced by the Industry Partner and provided to NASA during project execution. Each requirement specifies the verification method that will be used by NASA to verify the EPFD system requirements as well as a method that NASA recommends that the Industry Partner use to verify each requirement. The actual verification methods used by the Industry Partner may vary. Table 7 defines the verification methods.

4.0 EPFD SYSTEM REQUIREMENTS

This section contains the EPFD system level requirements.

4.1 Requirements that Primarily Support Driving Requirement 1 The following requirements are primarily traceable to DR 1: The EPFD integrated MW-class powertrain system ground and flight demonstration(s) shall reduce barrier technical risks associated with the system to enable U.S. industry to be first to market.

System Requirements that primarily support DR 1 SRD-01 - EPFD Transport Mission Types SRD-02 - Flight Test Environment SRD-03 - Data Rights

SRD-01 - EPFD Transport Mission Types

The EPFD integrated MW-class powertrain system flight demonstration(s) shall demonstrate integrated MW-class prowertrain technologies applicable to commercial aircraft transports for the single-aisle, regional, or thin haul markets.

Rationale:

The EPFD project is maturing integrated MW-class powertrains for use in EAP Vision Vehicles operating in the single-aisle, regional, or thin haul markets.

Verification Method:

NASA method: Analysis, Recommended method to Industry Partner: Demonstration

Traceability:

OBJ: 1, 3, 5

DR: 1, 2, 3, 7, 8

Allocation Project, SOO-Sections I, II, III

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SRD-02 - Flight Test Environment

The EPFD integrated MW-class powertrain system flight demonstration(s) shall occur at flight conditions (cruise altitudes and Mach) representative of commercial transports.

Rationale:

The operational environments for turboprop and turbofan transport aircraft are different. Turboprops typically cruise below 25kft at less than 0.5 Mach. Turbofan aircraft can cruise at altitudes greater 40kft at 0.7- 0.8 Mach. The operational EPFD flight test altitudes and Mach numbers should be representative of the associated EAP Vision Vehicle that the technology is being tested for. Refer to EPFD-02-06 Technical Measures of Effectivness.

Verification Method:

NASA method: Analysis, Recommended method to Industry Partner: Demonstration

Traceability:

OBJ: 1,2, 3, 5

DR: 1, 2, 3, 7, 8

ConOps: 4.1 6.2

Allocation SOO-Sections II, III

SRD-03 - Data Rights The data created by the Industry Partner during the conduct of this work, and provided to NASA, shall contain the appropriate marking identifying it as limited, and/or unlimited rights.

Rationale:

Data created under this contract will be marked accordingly to define the level of Government authorized use. Existing, prior Industry Partner owned data may be marked proprietary. Dissemination of data belonging to the government will facilitate reduction of barrier technical risks.

Limited rights data means data, other than computer software, that embody trade secrets or are commercial or financial and confidential or privileged, to the extent that such data pertain to items, components, or processes developed at private expense, including minor modifications.

Unlimited rights mean the rights of the Government to use, disclose, reproduce, prepare derivative works, distribute copies to the public, and perform publicly and display publicly, in any manner and for any purpose, and to have or permit others to do so.

Verification Method:

NASA method: Inspection, Recommended method to Industry Partner: Inspection

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Traceability:

OBJ: 1, 5

DR: 1, 7, 8

Allocation Multiple DRD’s

4.2 Requirements that Primarily Support Driving Requirement 2 The following requirements are primarily traceable to DR 2: The EPFD integrated MW-class powertrain system flight demonstration(s) shall demonstrate in flight high voltage operation at all relevant ground and flight conditions.

System Requirements that primarily support DR 2 SRD-04 - Flight Test Demonstration of high voltage Integrated MW-class powertrain systems SRD-05 - Flight Test Demonstration of high power Integrated MW-class powertrain systems SRD-06 – Electromagnetic Interference (EMI) and Electromagnetic Compatibility (EMC) SRD-07 – Demonstrate an Energy Storage System SRD-08 - EPFD Propulsion during Flight Phases

SRD-04 - Flight Test Demonstration of high voltage Integrated MW-class powertrain systems

The EPFD integrated MW-class powertrain system flight demonstration shall conduct flight tests of a MW-class, integrated, high voltage electrical propulsion system.

Rationale:

EPFD will demonstrate technologies and vehicle-level integration of high-voltage (MW class) electrified aircraft propulsion systems with advanced airframe systems to small transport aircraft. Refer to EPFD-02-06 Technical Measures of Effectivness Table 7 for voltage levels.

Verification Method:

NASA method: Analysis, Recommended method to Industry Partner: Demonstration

Traceability:

OBJ: 1, 2, 3, 5

DR: 1, 2, 3, 5, 6, 7, 8, 9

Allocation SOO-Section II, III

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SRD-05 - Flight Test Demonstration of high power Integrated MW-class powertrain systems The EPFD integrated MW-class powertrain system flight demonstration shall shall conduct flight tests with MW power levels required for MW-class powertrains.

Rationale: The primary focus of EPFD is MW-class systems. Refer to EPFD-02- 06 Technical Measures of Effectivness Table 7.

Verification Method:

NASA method: Analysis, Recommended method to Industry Partner: Demonstration

Traceability:

OBJ: 1, 3

DR: 1, 2, 7

Allocation SOO- Section II, III

SRD-06 – Electromagnetic Interference (EMI) and Electromagnetic Compatibility

(EMC)

The EPFD integrated MW-class powertrain system flight demonstrator(s) shall demonstrate correct operation of production aircraft systems and MW-class powertrain systems in a common electromagnetic environment.

Rationale:

A MW-class electric propulsion system is four times higher power than typical state of the art aircraft electrical systems and often exhibit high frequency switching that can potentially lead to radiated and conducted electromagnetic interference (EMI) onto other aircraft systems (e.g.

production aircraft systems). The integrated MW-class powertrain system will necessitate robust subsystem level EMI/EMC protections be developed for this unique application with the goal to prevent failure modes during integration while preventing unintended collateral impact to existing robust high Technical Readiness Level (TRL) aircraft systems. Subsystem EMI/EMC testing will identify conditions early, prior to integration, preventing damage to neighboring systems. This will ensure integrated MW-class powertrain aircraft remain safe for continued safe flight and landing through the planned range of flight conditions. Existing standards such as “DO-160, Environmental Conditions and Test Procedures for Airborne Equipment” may be used as the basis for EMI/EMC testing.

Verification Method:

NASA method: Analysis, Recommended method to Industry Partner: Test

Traceability:

OBJ: 2, 3, 5

DR: 1, 2, 8

Allocation DRD SM-08

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SRD-07 – Demonstrate an Energy Storage System

The EPFD integrated MW-class powertrain system flight demonstration(s) shall demonstrate an electrical energy storage system as part of the integrated MW-class powertrain capable of operating in the flight environment compatible with the Electrified Aircraft Propulsion Vision Vehicle.

Rationale:

The integrated MW-class powertrain flight demonstration(s) will demonstrate an electrical energy storage system with capablity levels that trace to the needs to the related Vision Vehicle. Electrical energy storage systems for this application typically will operate at significantly higher voltages and much higher energy levels than current aircraft systems.

Verification Method:

NASA method: Analysis, Recommended method to Industry Partner: Demonstration

Traceability:

OBJ: 2, 3

DR: 1, 2, 3, 7

ConOps: 3.2

Allocation Directly to Industry Partner

SRD-08 - EPFD Propulsion during Flight Phases

The EPFD integrated MW-class powertrain system shall have the capability to demonstrate electrified aircraft propulsion during any phase of ground and flight that the system would be used for the associated EAP Vision Vehicle .

Rationale:

The flight test aircraft should utilize an integrated MW-class powertrain system during the mission phases where electrified aircraft propulsion is planned for use in the related Vision Vehicle.

Flight phases include taxi, takeoff, climb, cruise, descent, approach and landing.

Verification Method:

NASA method: Analysis, Recommended method to Industry Partner: Demonstration

Traceability:

OBJ: 1, 2, 3, 5

DR: 1, 2, 3, 5, 7, 8

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4.3 Requirements that Primarily Support Driving Requirement 3 The following requirements are primarily traceable to DR 3: The EPFD integrated MW-class powertrain system flight demonstration(s) shall conduct crewed (human rated) flight operations and testing.

System Requirements that primarily support DR 3 SRD-09 - EPFD Crewed Flight Testing SRD-10 - Airworthiness and Flight Safety Review Process SRD-11 – Industry Partner Proposed Airworthiness Process.

SRD-12 - Environmental Testing SRD-13 - Structural Airworthiness Requirements SRD-14 – Software Requirements

SRD-09 - EPFD Crewed Flight Testing

The EPFD integrated MW-class powertrain system flight demonstration(s) shall conduct human crewed flight testing.

Rationale: The integrated MW-class powertrain technologies will be flown on crewed, passenger carrying aircraft.

Verification Method:

NASA method: Inspection, Recommended method to Industry Partner: Demonstration

Traceability:

OBJ: 1, 2, 3, 5

DR: 1, 2, 3, 5, 6, 7, 8

ConOps: 3.1.1

Allocation Directly to Industry Partner

SRD-10 - Airworthiness and Flight Safety Review Process Airworthiness approval for the EPFD flight demonstrations shall follow the airworthiness and flight safety review process as described in NPR 7900.3d.

Rationale:

In order to ensure an airworthiness and flight safety review process that is tailorable to the partners objectives and consistent with NPR 7900.3d, Verification Method:

NASA method: Analysis, Recommended method to Industry Partner: Analysis

Traceability:

OBJ: 2, 3

DR: 3, 5, 6

ConOps: 6.2.1

Allocation DRD SE-22

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SRD-11 – Industry Partner Proposed Airworthiness Process.

The EPFD integrated MW-class powertrain system flight demonstrator Industry Partners shall present their airworthiness process to NASA for acceptance.

Rationale:

As outlined in NPR 7900.3d, the airworthiness process may be tailored and may include a process proposed by contract awardees.

The process should be coordinated with EPFD project technical authority.

Verification Method:

NASA method: Analyisis, Recommended method to Industry Partner: Analysis

Traceability:

OBJ: 2, 3

DR: 3, 5, 6

SRD-12 - Environmental Testing

The novel MW-class powertrain components that will be flown on EPFD integrated MW-class powertrain system flight demonstrator(s) shall demonstrate successful environmental tests in support of airworthiness, with tailored environmental testing standards that are appropriate for commercial transport flight environments.

Rationale:

Integrated MW-class powertrain systems must be safely demonstrated in flight. One of the desired outcomes for the EPFD project is to develop environmental testing standards that account for high voltage and high power MW-class Electrified Aircraft Propulsion technologies. Given a number of unprecedented altitude dependent high voltage and power electrical boundary conditions in this TRL raising activity, additional specifications will be needed when tailoring existing environmental qualification and acceptance metrics. EPFD partners should propose the environmental testing standards that will be tailored to ensure airworthiness of integrated MW-class components that will be used on the demonstrator aircraft. Existing standards such as “DO-160, Environmental Conditions and Test Procedures for Airborne Equipment,” and “AFOP-7900.3-004, Environmental Acceptance Testing: Electronic & Electromechanical Equipment,” may be used as the basis for developing these standards.

Verification Method:

NASA method: Inspection Recommended method to Industry Partner: Test

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OBJ: 1, 2, 3, 5

DR: 1, 2, 3, 5, 6, 8

Allocation DRD SM-04, SM-08, SE-22

SRD-13 - Structural Airworthiness Requirements

EPFD Industry Partners shall develop an airworthiness approach for integration of MW-Class powertrain technologies into the flight test aircraft structures.

Rationale:

Integrated MW-class powertrain systems must be safely tested in flight.

Structural modifications will be required for integration of any integrated MW-class powertrain technology into the flight test aircraft.

This will have and impact on static and dynamic structures. The Industry Partner should propose a structural airworthiness process.

NASA AFRCdocument, AFG-7123.1-001 "Aircraft structural safety of flight guidelines" may be to be referred to for guidance.

Verification Method:

NASA method: Analysis Recommended method to Industry Partner: Analysis

Traceability: DR: 3

SRD-14 – Software Requirements

The software development approach used by the Industry Partners shall be tailored to comply with NPR 7150.2C NASA Software Engineering Requirements and NASA-HDBK-2203B, NASA Software Engineering Handbook.

Rationale:

Industry Partner(s) under contract are required to follow NASA software engineering requirements for safety critical software developed as part of EPFD. The EFPD Software Management Plan is based on NPR 7150.2C and allows provisions for Industry Partner(s) to use DO-178C (Software Considerations in Airborne System and Equipment Certification, DO- 178C), which is the standard used by most commercial aircraft developers.

Verification Method:

NASA method: Inspection Recommended method to Industry Partner: Inspection

Traceability: DR: 3

Allocation DRD SW-01, SW-02, SW-03

Effective Date: Page 17

4.4 Requirements that Primarily Support Driving Requirement 4 The following requirements are primarily traceable to DR 4: The EPFD integrated MW-class powertrain system flight demonstration(s) shall conduct first flight no later than 2023 if feasible and no later than March of 2024. Spiral developments may extend into 2025..

System Requirements that primarily support DR 4 SRD-15 - First Flight No Later Than Date

SRD-15 - First Flight No Later Than Date

The EPFD flight demonstration(s) should perform first flight no later than 2023 if feasible and no later than March of 2024.

Rationale:

To meet Stakeholders Expectations and the timeline for technology development that enables insertion into industry commercial vision vehicles, EPFD first flight is required to occur no later than March 2024. Spiral developments may extend into 2025.

Verification Method:

NASA method: Inspection Recommended method to Industry Partner: Inspection

Traceability:

OBJ: 1, 4

DR: 1, 4

Allocation Project, Directly to Industry Partner

4.5 Requirements that Primarily Support Driving Requirement 5 The following requirements are primarily traceable to DR 5: The EPFD integrated MW-class powertrain system flight demonstration(s) shall demonstrate in flight a thermal management system for the electrical power system.

System Requirements that primarily support DR 5 SRD-16 - Thermal Management System SRD-17 - Hot Day Operations

Effective Date: Page 18

SRD-16 - Thermal Management System The EPFD integrated MW-class powertrain system flight demonstrator(s) shall demonstrate in-flight a thermal management system for the integrated MW-class powertrain.

Rationale:

Thermal management for MW-class powertrain systems is a challenge because large amounts of waste heat are produced at relatively low rejection temperatures. Thermal management must be considered through all phases of operation.

Verification Method:

NASA method: Analysis Recommended method to Industry Partner: Demonstration

Traceability:

OBJ: 3

DR: 5

Allocation Directly to Industry Partner

SRD-17 - Hot Day Operations

The EPFD integrated MW-class powertrain system shall be capable of demonstrating integrated MW-class powertrain technology at SAE AS210 10% hot day conditons during ground and takeoff operations.

Rationale:

The thermal management system must function properly under all expected operating conditions, including Hot Day Operations. This requirement does not imply that the aircraft must perform flight demonstrations at EAFB under hot day conditions.

The Industry Partner shall design the integrated MW-class powertrain system to the temperatures in SAE international AS210 “Definition of Commonly Used Day Types (Atmospheric Ambient Temperature Characteristics Versus Pressure Altitude),” Table A10 which provides 10% Hot Day temperature versus pressure altitude based on Table XIX, “Supplementary High Temperature Values for the Worldwide Air Environment”, of MIL- HDBK-310, dated 9 January, 1987.

Example: Table A10 lists a temperature of 113° F (45° C) at a pressure altitude of 0 ft (0 m).

Verification Method:

NASA method: Analysis Recommended method to Industry Partner: Analsyis

Traceability:

OBJ: 2, 3

DR: 2, 5, 8

Effective Date: Page 19

4.6 Requirements that Primarily Support Driving Requirement 6

The following requirements are primarily traceable to DR 6: The EPFD integrated MW-class powertrain system flight demonstration(s) shall demonstrate in flight a control system which manages electrical faults while maintaining fail-safe aircraft operations.

System Requirements that primarily support DR 6 SRD-18 - Fault Control System

SRD-18 - Fault Control System

The EPFD integrated MW-class powertrain system shall demonstrate in-flight a control system that detects, mitigates, and safely manages electrified powertrain system faults.

Rationale:

The integrated MW-class powertrain requires robust protection functions for electrically related faults (e.g. ground faults, line-to-line low and high impedance faults) that can potentially impact the propulsion system and other aircraft systems. Fault detection, isolation, and reporting need to be demonstrated. A fail-safe design will detect and mitigate failures using both software and hardware approaches. In addition, fail safe operation should be demonstrated with faults being isolated. Cascading failures and collateral impact to aircraft systems should be avoided.

Verification Method:

NASA method: Analysis Recommended method to Industry Partner: Demonstration

Traceability:

OBJ: 1, 3, 5

DR: 1, 3, 6

Effective Date: Page 20

4.7 Requirements that Primarily Support Driving Requirement 7 The following requirements are primarily traceable to DR 7: The EPFD integrated MW-class powertrain system flight demonstration(s) shall measure the performance of the system against the technical performance metrics (TPMs) – Reference EPFD 02-06 for TPMs.

System Requirements that primarily support DR 7 SRD-19 - Obtain Integrated MW-class Powertrain Test Data In-Flight SRD-20 - Removed SRD-21 - Engineering Units

SRD-19 - Obtain Integrated MW-class Powertrain Test Data In-Flight

The EPFD integrated MW-class powertrain system flight demonstration(s) shall obtain in-flight test data of the integrated MW-class powertrain systems and components.

Rationale:

Integrated MW-class powertrain system flight data is need to validate electrified powertrain systems and components in a relavant environment.

This data will directly support EPFD risk mitigations, regulation and standard development and technology readiness level progression. The flight data plan will drive the instrumentation sensor allocation, redundancy and placement locations derived from system test requirements during project development. This data should be recorded in flight for post-processing and analysis on ground. The Industry Partners will develop a Master Measurement List (MML) that will be provided to the NASA EPFD project.

Verification Method:

NASA method: Analysis Recommended method to Industry Partner: Demonstration

Traceability:

OBJ: 3

DR: 2, 5, 7, 9

Allocation DRD SE-13, SE-16, SE-23, SE-24

SRD-20 - Removed

Effective Date: Page 21

SRD-21 - Engineering Units Data from the EPFD industry partner shall be provided with both The United States Customary Units (USCU) – length (feet, ft), force (pound-force, lbf), temperature (degrees Fahrenheit, °F), mass (slug), and time (seconds, s) and equivalent International System of Units (SI) values in parentheses.

Rationale:

By declaring the preferred units of engineering ensures a common set of units throughout the EPFD project.

Example format: 10.00 ft (3.05 m).

Verification Method: NASA: Inspection, Industry Partner: Inspection

Traceability:

OBJ: 1

DR: 7, 8, 9

Allocation Project, Contract

Effective Date: Page 22

4.8 Requirements that Primarily Support Driving Requirement 8 The following requirements are primarily traceable to DR 8: The EPFD integrated MW-class powertrain system flight demonstration(s) shall provide ground and flight test data to address gaps in regulations and standards associated with system application to commercial transport aircraft.

System Requirements that primarily support DR 8 SRD-22 – Identify & Develop Standards Identified In Regulations and Standards Gap Analysis SRD-23 - Dissemination of MW-Class Powertrain data

SRD-22 – Identify & Develop Standards Identified In Regulations and Standards Gap

Analysis The EPFD Project team, consisting of NASA and industry partners, shall work with US aviation to identify and address the standards to support means-of-compliance for the highest priority gaps identified by gaps in the current regulations in Title 14 of the Code of Federal Regulations (CFR) Chapter I, Subchapter C, Aircraft that enables timely market introduction of integrated MW-class powertrain system technology in commercial aircraft.

Rationale:

Electrification of aircraft and its technology are evolving more rapidly than the Regulations and Standards necessary to support them. An Assessment of the regulations is required to identify gaps in the current regulations, and identify the highest priority standards that need to be developed. The regulations for the aircraft and technology of interest to the EPFD Project is focused on Title 14 of the Code of Federal Regulations (CFR) Part 33, Aircraft Engines. In addition, Turbofan aircraft will also examine 14 CFR Part 25, Large Transport Category Aircraft. Finally, Turboprop aircraft will examine both 14 CFR Part 23, Normal Category Aircraft, and Part 35, Propellers, in addition to 14 CFR Part 33. The identified highest priority competitive and pre-competitive (Unlimited Rights) MW-class electrified aircraft propulsion regulations and standards gaps will be documented, and recommended means-of-compliance will inform the development of new standards, and potentially updating regulations.

Verification Method:

NASA method: Analysis, Recommended method to Industry Partner: Demonstration, Analysis

Traceability:

OBJ: 5

Allocation Project, SOO Section II, DRD SE-02

Effective Date: Page 23

SRD-23 - Dissemination of MW-Class Powertrain data

EPFD Project team, consisiting of NASA and Industry Partners, shall disseminate non-proprietary MW-class powertrain ground and flight test data and regulatory gap data of component technologies and integrated systems to the broader community.

Rationale:

This requirement affirms NASA's commitment to publish information and data arising from technology development projects. This information and data will be available to the technical community and the general public as agreed upon with Industry Partners. Data and reports shall be provided in an unlimited rights version and a government purposes version.

Verification Method:

NASA: Inspection, Recommended method to Industry Partner: Inspection

Traceability:

OBJ: 1, 4, 5

Allocation Project, Directly to Industry Partner

4.9 Requirements that Primarily Support Driving Requirement 9 The following requirements are primarily traceable to DR 9: The EPFD integrated MW-class powertrain system flight demonstration(s) shall acquire ground and flight data used to validate NASA modeling tools and research.

System Requirements that primarily support DR 9 SRD-24 - Obtain Integrated MW-Class Powertrain Ground Test Data SRD-25 - EPFD Ground Testing SRD-26 - Pre/Post System Performance Model Data

SRD-24 - Obtain Integrated MW-Class Powertrain Ground Test Data

The EPFD Industry Partners shall obtain test data from the integrated MW-class powertrain systems and components during ground demonstration(s).

Rationale:

Ground test data from the integrated MW-class powertrain system is need to characterize the integrated MW-class powertrain prior to the flight test. This data will directly support EPFD risk mitigations, regulations and standards development, technology readiness level progression and integration onto the EPFD aircraft.

Verification Method:

NASA: Inspection, Recommended method to Industry Partner: Inspection

Traceability:

OBJ: 2, 5

DR: 1, 2, 8, 9

Allocation SOO-Section I, II, III, DRD SE-12, SE-13, SE-16

Effective Date: Page 24

SRD-25 - EPFD Ground Testing

The EPFD Industry Partners shall conduct selected ground demonstration(s) of the integrated MW-class powertrain system to raise TRL level and validate performance ahead of the flight demonstration.

Rationale:

Integrated testing of integrated MW-class powertrain hardware and software at the power levels expected during flight is essential to ensuring a successful demonstration. Ground tests may be performed in a laboratory, an environmental facility, and/or on a copper bird to evaluate integrated MW-class powertrain systems and components at conditions that are representative of flight conditions when possible.

Verification Method:

NASA: Analysis, Recommended method to Industry Partner: Analysis, Demonstration

Traceability:

OBJ: 2, 5

DR: 1, 2, 8, 9

Allocation SOO-Section I, II, DRD SE-12, SE-13, SE-16

SRD-26 - Pre/Post System Performance Model Data The EPFD industry partner shall provide pre-test mathematical model data, and post-test mathematical model data of their integrated MW-class powertrain system, reasonably validated with the assessed uncertainty of the resulting ground and fight test data.

Rationale:

Data and analytical models will be used as the basis of a demonstration-by-analysis framework for performance assessment of EAP Vision Vehicles. Technical performance measurements will be used to track progress on the integrated MW-class powertrain and used to estimate performance of that system in a range of reference EAP Vision Vehicles. The model data along with ground and flight data, will be used to validate internal NASA tools that predict Electrified Aircraft Propulsion system performance for future aircraft design.

Verification Method:

NASA: Analysis, Recommended method to Industry Partner: Analysis

OBJ: 3

DR: 1, 2, 9

Allocation Project, DRD SE-09

Effective Date: Page 25

APPENDIX A EPFD PROJECT NEEDS, GOALS AND OBJECTIVES

A.1 EPFD Project Need

The need for EPFD is found in the NASA ARMD Strategic Thrust 3 and Critical Commitment 3.1

Table 5 - ARMD Needs from NASA Critical Commitment

Strategic Thrust Critical Commitment 3 Ultra-Efficient Subsonic Transports:

Realize revolutionary improvements in economics and environmental performance for subsonic transports with opportunities to alternative propulsion and energy.

3.1 Demonstrate practical vehicle-level

integration of MW-class electrified aircraft propulsion systems, leveraging advanced airframe systems to reinvigorate the regional and emerging smaller aircraft markets and strengthen the single aisle aircraft market.

A.2 EPFD Project Goals Goal 1: Collaborate with United States (U.S.) Industry and other NASA projects on EAP development, flight testing, flight test instrumentation, and range support.

Goal 2: Conduct necessary ground demonstrations of integrated electrified aircraft propulsion systems with U.S. Industry to support flight test.

Goal 3: Conduct flight testing of a crewed aircraft with an electrified aircraft propulsion powertrain system with U.S. Industry.

Goal 4: If possible, within the specified time frame and budget, allow for spiral developments of EAP technology.

Goal 5: Will plan ground and flight test campaigns to provide appropriate data to address gaps in regulations and standards.

A.3 EPFD Project Objectives Objective 1 Develop partnership agreements, including contractual arrangements, with U.S.

industry for EAP technology development and flight testing to enable rapid technology transition to the U.S. fleet. (Traces to Goal 1) Objectives 2: Conduct Technology Maturation and risk reduction ground tests of MW-class, powertrain components and system to support flight testing. (Traces to Goal 2) Objective 3: Flight demonstrate technologies for practical vehicle-level integration of high power (MW-class) electrified aircraft propulsion systems maturation to a TRL 6. (Traces to Goal 3) Objective 4: If possible, within the specified time frame and budget, provide a flexible architecture to demonstrate additional, emerging technology with flight test insertions. (Traces to Goal 4) Objective 5: Collaborate with Flight Demonstration and Capabilities (FDC) project personnel and U.S. Industry to identify regulation and standards gaps and through ground and/or flight testing. (Traces to Goal 5)

Effective Date: Page 26

APPENDIX B EPFD VERIFICATION MATRIX

Table 6 -SRD Verification Matrix

Inspection Analysis Demonstrate Test

SRD-01 NASA IP

SRD-02 NASA IP

SRD-03 NASA, IP

SRD-04 NASA IP

SRD-05 NASA IP

SRD-06 NASA IP

SRD-07 NASA IP

SRD-08 NASA IP

SRD-09 NASA IP

SRD-10 NASA, IP

SRD-11 NASA, IP

SRD-12 NASA IP

SRD-13 NASA, IP

SRD-14 NASA, IP

SRD-15 NASA, IP

SRD-16 NASA IP

SRD-17 NASA IP

SRD-18 NASA IP

SRD-19 NASA IP

SRD-20 Removed

SRD-21 NASA, IP

SRD-22 NASA, IP

SRD-23 NASA, IP

SRD-24 NASA, IP

SRD-25 NASA, IP IP

SRD-26 NASA, IP

NASA: Indicates the verification method that the EPFD project will use to verify this requirement.

IP: Indicates the desired verification method that the EPFD expects the Industry Partner (IP) will use to verify this requirement.

Effective Date: Page 27

Table 7 - EPFD Verification Methods

Verification Methods* *V&V Plan’s method definitions have precedence

Inspection

This method of verification is the examination of documentation or physical characteristics that determines compliance of the item with requirements without the use of special laboratory equipment, procedures, test support items, or services. Inspection uses standard methods such as visuals, gauges, etc., to verify compliance with requirements.

Analysis

This method of verification utilizes techniques and tools such as computer and hardware simulations, analog modeling, similarity assessments, and validation of records to confirm that design requirements to be verified have been satisfied. Analysis is the evaluation of the results of multiple tests and analyses at a lower level as it would apply to a higher level of assembly.

Demonstration

This method of verification is a qualitative exhibition of functional performance (i.e. serviceability, accessibility, transportability and human engineering features) usually accomplished with no or minimal instrumentation.

Test

This method of verification is a method where requirements are verified by quantitative measurement during or after the controlled application of functional and environmental stimuli.