Tailored Systems Engineering Approach

In order to gather the information needed to answer the previously posed questions and to address research objectives, a tailored SE approach was proposed. As the scope of the effort was limited to the evaluation of a prototype HE-RPA, the SE efforts focused on pre-systems acquisition events. The Defense Acquisition Guidebook (DAG) [34] provides a framework that allows acquisition professionals to develop and procure systems for the Defense Department in accordance with DoD directives. The DAG addresses these pre-acquisition events within the Defense Acquisition Management System depicted in Figure 10. The pre-systems acquisition phase includes materiel solution analysis and technology development; however, the vast majority of this effort was centered on the technology development phase. The equivalent of a materiel

development decision for this project was essentially concluded via a previous decision to explore the HE-RPA concept as a materiel solution versus alternate doctrine,

organization, training, material, leadership, personnel, or facilities (DOTMLPF) solutions [35].

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Narrowing the scope to essentially the technology development phase was a key aspect of utilizing a tailored systems engineering approach to perform the concept evaluation of the HE-RPA within a compressed development cycle. The inherent constraints of the technology development phase limited the scope of this effort to the development and demonstration of a prototype system, which was consistent with the previously mentioned limitations of this effort. The HE-RPA was considered an emerging technology and had not yet been successfully demonstrated [12] , making a comparative analysis to other HE-RPA technology difficult. A key component of the concept evaluation was to determine the potential performance improvements resulting from inclusion of the HEPS over a baseline configuration. Therefore, a component of the systems engineering approach was to include the development and baseline evaluation of an RPA powered by an ICE propulsion system. All aspects of the tailored SE process were therefore needed to account for two airframes; airframe 1 (ICE powered) and airframe 2 (HE powered).

Although tailored for the evaluation of the HE-RPA, the selected approach still encompasses most of the elements associated with robust systems engineering. These elements were represented by the systems engineering V-model depicted below in Figure 11.

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Figure 11:Systems Engineering V-Model [36]

The tailored SE approach leverages previous HE-RPA conceptual studies [10, 11, 20] to create a CONOPS, and the generation of systems architecture to define system requirements and to allocate system functions to subsystems. This approach also utilizes a team concept somewhat resembling an integrated product team. Team members included the authors, along with Ausserer [12] and Giacomo [13]; contributing to development of the HE propulsion system and airframe characterization, respectively.

At project initiation, the HE-RPA development team decided to use the following SE principles as the foundation of the tailored SE process used in this research.

 Event driven

 Defined entry and exit criteria  Value added

 Formal and informal format

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The HE-RPA development team also identified the following systems engineering activities as critical for the development of the HE-RPA and essential to the tailored SE process.

 Preliminary design review

 Developmental test and evaluation  DoD architecture framework  Human factor/systems integration  Critical design review

 Prototype/engineering development model  Risk assessment

 System requirements review

 Systems engineering and technology development  Test & evaluation master plan (TEMP)

 Test Readiness Review/ Safety review Board

Early identification and solidification of primary research objectives and

evaluation criteria/questions lead to the generation of measures of effectiveness (MOEs) and measures of performance (MOPs) for testing captured in the TEMP, Appendix K. Previous work conducted by Greiser [24], Rotramel [14], and Mengistu [25] along with concurrent work by Ausserer [12] were utilized and tracked via an evolving integrated master schedule (IMS) in order to establish a detailed design for the HEPS. The tailored

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SE approach took advantage of previous work by Harmon et al [11, 20] and Hiserote [20], as well as ongoing efforts by Giacomo [13] for airframe design parameters for the HE-RPA. The component level designs were evaluated in order to identify only those performance characteristics and parameters that contributed to meeting the overarching research objectives and evaluation criteria.

The test planning and evaluation techniques of these objectives are addressed within the TEMP (Appendix K) and the evaluation section which follows later in Chapter III. As this effort was focused on the technology development phase with a prototype system, component and system verification utilized a build-up approach, incorporating three main levels of testing; functionality, safety, and performance. Functionality testing focused on basic system operation and is intended to verify system design and operation. The HE-RPA incorporated potentially hazardous systems; therefore, it was critical that the safety aspects of the system be vetted via the planned risk mitigation efforts and safety review boards. Ultimately, the performance of the HE-RPA needed to be

characterized by the development team in order evaluate the concept. Therefore, ground testing and flight testing were conducted in order to collect sufficient information. Testing and evaluation results are discussed in detail in Chapter IV.

As mentioned previously, time was the primary constraint to this effort.

Therefore, risk analysis and risk management strategies were implemented throughout, with utmost attention on schedule risk. Risk is further addressed later in this chapter, section 3.8.

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A key aspect of evaluating the hybrid-electric RPA concept using a tailored SE process was following an event driven process focused on just the elements deemed necessary to evaluate the prototype system against the CONOPS. The generation of an initial IMS ensured all events were planned in a logical and sequential manner. The IMS was also critical to monitoring progress and managing risk.