Regulatory pathways to certifiable condition based maintenance solutions in aviation: A comprehensive review

Aircraft maintenance is characterized by strict regulations to ensure airworthiness throughout an air vehicle’s complete lifetime. While the traditional maintenance approach of regular inspections and functional checks has led to extraordinary high levels of safety, it is also cause for considerable maintenance-related downtimes and substantial operating cost contributions. At the same time, the vast majority of performed inspections does not reveal any defects and will leave the aircraft’s condition unchanged. Therefore, the promise of substantial cost savings pushes manufacturers and operators constantly towards replacement of those tasks by automated Condition Monitoring (CM) and Health Management (HM) systems. However, regulatory guidance for the development of certifiable HM solutions to substitute manual scheduled maintenance tasks by Condition Based Maintenance (CBM) approaches is sparse. Consequently, the introduction of these technologies remains slow while current use cases are limited to non-critical maintenance tasks or the avoidance of unscheduled maintenance events due to system breakdowns. With this work, we will provide an in-depth review of existing guidelines from (a) regulatory authorities, (b) institutions such as SAE and the International Organization for Standardization (ISO), and (c) academic publications. Using these insights, we will derive a holistic framework that provides HM experts a guiding document to support their development of certifiable technical solutions. As a result, this guidance will help to exploit the existing technical capabilities for a continuous CM to determine airworthiness statuses and to replace scheduled preventive maintenance tasks by automation.