Development of FMEA for Direct Field Acoustic Testing (DFAN)

The implementation of Direct Field Acoustic Testing (DFAN) for large-scale test articles is gaining prominence due to its logistical advantages over conventional RFAT testing. In preparing to conduct DFAN testing on a reusable spaceplane project—a test article exceeding ten meters in height—ARS has undertaken an extensive Failure Modes and Effects Analysis (FMEA) aimed at large-scale DFAN configurations. By identifying potential failure modes and their associated consequences, ARS has crafted standard operating procedures (SOPs) that prioritize the safety, health and welfare of personnel and flight hardware.

The FMEA for the proprietary Neutron™ system was carried out by a multidisciplinary team of subject matter experts with vast experience in flight hardware, test planning, construction practices, and the execution of acoustic tests. The analysis addressed failure modes such as personnel safety during the loading and stacking of large-scale acoustic devices, usage of overhead lifting fixtures, structural stability during construction and acoustic exposure of personnel and adjacent flight hardware during testing. Each failure mode’s probability, severity and detection were evaluated to quantify risks and prioritize actions within the SOPs effectively.

One exemplary application of FMEA can be observed in ARS’s internal policies and SOPs concerning the Neutron™ 104 Lifting Fixture and associated rigging hardware. The use of below-the-hook lifting devices for overhead rigging introduces several potential failure modes affecting both personnel safety and the integrity of flight hardware. Failures in rigging hardware, for example, could stem from structural defects, improper use or connection of equipment or lifting loads beyond the specified safe working load. Consequences of such overhead rigging failures could include damage to the lifted object or harm to personnel and flight hardware below the fixture at the time of failure. Although severe, these risks can be detected and mitigated, thus reducing their probability of occurrence. Mitigation strategies include annual load testing of rigging, visual inspections of structures and connection points prior to lifting and displaying the safe working load on lifting hardware, revalidated annually by a certified testing facility. Additional safety measures include the use of hardhats and the clearance of areas below suspended loads during lifting operations.

Unique challenges often present unique opportunities for industry growth and development. Utilization of FMEA has enabled ARS to identify blind spots in traditional protocols and continuously promote the industry’s progress toward safe and effective DFAN practices.

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