Bowtie Methodology for Risk Analysis of Visual Borescope Inspection during Aircraft Engine Maintenance

Abstract

Background—The inspection of aircraft parts is critical, as a defective part has many potentially adverse consequences. Faulty parts can initiate a system failure on an aircraft, which can lead to aircraft mishap if not well managed and has the potential to cause fatalities and serious injuries of passengers and crew. Hence, there is value in better understanding the risks in visual inspection during aircraft maintenance. Purpose—This paper identifies the risks inherent in visual inspection tasks during aircraft engine maintenance and how it differs from aircraft operations. Method—A Bowtie analysis was performed, and potential hazards, threats, consequences, and barriers were identified based on semi-structured interviews with industry experts and researchers’ insights gained by observation of the inspection activities. Findings—The Bowtie diagram for visual inspection in engine maintenance identifies new consequences in the maintenance context. It provides a new understanding of the importance of certain controls in the workflow. Originality—This work adapts the Bowtie analysis to provide a risk assessment of the borescope inspection activity on aircraft maintenance tasks, which was otherwise not shown in the literature. The consequences for maintenance are also different compared to flight operations, in the way operational economics are included.

Aircraft Trajectory Tracking Using Radar Equipment with Fuzzy Logic Algorithm

“…The fact that a target with the characteristics of a military aircraft can accelerate, turn, execute quick maneuvers, thus turning away from a trajectory with constant speed due to the orders received and due to the atmospheric turbulences, makes the pursuit of a target a difficult task. In order to handle these problems, different approach models have been developed [22]. These models are usually developed based on some statistic models regarding the measurement and processing of noise and target dynamics.…”

A Systematic Methodology for Developing Bowtie in Risk Assessment: Application to Borescope Inspection

“…As per the ICAO Safety Management Manual, a hazard is defined as "condition, object, process or activity with the potential of causing harm or damage, including injuries to personnel, damage to equipment, properties or environment, loss of material or reduction in ability to perform a prescribed function" [27]. Previous work showed that Bowtie is a useful tool for such risk assessments, but has some limitations, such as the process of constructing a Bowtie being ad hoc and arbitrary [7]. It highly depends on expert knowledge and the personal preferences and outlook of the analyst [4,[20][21][22].…”

“…The next step is defining the top event, which describes the release or loss of control over the hazard. "It has not caused any damage or negative impact yet, but can lead to undesired outcomes if all prevention barriers fail" [7]. The terminology of the 'top event' originates form the fault tree analysis.…”

“…The method is especially good at visually representing the event chains from the root cause to the consequence and identifying barriers that are in place, missing or ineffective. Industries in which the Bowtie method is particularly popular include oil and gas [1,2], aviation [3][4][5][6][7], transportation [8][9][10], chemical and process [11,12], mining [2,13], IT [14][15][16], and medical [17][18][19].…”

“…A high-level MRO process with the different borescope inspection procedures and related risks is presented in Figure 1. Previous work showed that Bowtie is a useful tool for such risk assessments, but has some limitations, such as the process of constructing a Bowtie being ad hoc and arbitrary [7]. It highly depends on expert knowledge and the personal preferences and outlook of the analyst [4,[20][21][22].…”