## 1 Introduction
In particular, an excellent FMECA team was mentioned in the paper who efficiently identified the faults in a new system design. As mentioned earlier, the advantages of using FMECA in the reliability evaluation process are that it can identify the root causes of the failures and develop corrective actions, as well as helping the reliability analysis to be conducted efficiently through interventions at the system design stage. For example, in the failure analysis of a heavy-duty diesel engine piston [12], the use of FMECA to identify the piston failure modes reduced the engine maintenance costs. In addition, scholars [13] have also assessed the risks of vehicles in operation. Scholars have also used fuzzy FMECA to identify the potential failure modes and hazards of a vehicle turbocharger [14] and a fighter engine [15]. Lastly, FMECA was applied to identify the failure modes and hazards of key components in an automotive diesel engine [16]. FHA is widely used for the risk assessment of new systems [17]. The authors of [18; 19] summarized the advantages and disadvantages of using FHA in the application process. In air transportation, it provides reliable references for civil aviation flight safety to improve the safety and reliability of aircraft resistance runway mechanisms [20] and aviation aircraft systems [21]. Similarly, FHA can minimize the time that is required for civil aircraft airworthiness qualification and improve safety [22]. In addition, combined with gray system theory [23], FHA was used to establish a comprehensive application method for the safety assessment of aircraft landing gear. Lastly, the combination of FHA and system theoretical process analysis (STPA) was applied to the risk assessment of new electric vertical lift vehicles [24] in the operational stage. FTA has a wide range of applicability within the existing literature [25]. Many studies have described the applicability of this method [26; 27]. In the field of road traffic, FTA was used for the risk assessment of a gantry crane system [28], including the power system of the crane, to meet the safety requirements of the vehicle during operation. Others have also combined FTA with the Monte Carlo algorithm [29] for the risk assessment of rail vehicles, thereby minimizing the stopping time and improving the reliability of the rail vehicles. In [30], [PERSON] analyzed the reliability of unmanned vehicles by combining state transition diagrams with FTA in order to solve the problems that are encountered in the concept design stage of unmanned vehicles, which provided some references for the design and analysis of unmanned vehicle systems. Lastly, [PERSON] [31] used FTA to assess the potential failure risks of key power equipment in EVs and put forward comprehensive and forward-looking development recommendations for improving the safety of EVs. In the existing studies, a FRACAS has often been used in the development and design of new complex systems [32] to facilitate fault management during system operation or maintenance. The FRACAS has often been used in combination with other reliability assessment methods in many of the existing studies and its compatibility has been documented in many references [33; 34]. In the aerospace industry, a FRACAS was used to control the reliability of unmanned aerial vehicles [35] throughout their life cycle. In addition, the reliability control of locomotives and vehicles was carried out by combining a FRACAS with the FMECA method [36]. As a result, the surface method provided an increase in true reliability with the best turnaround time. Lastly, a FRACAS was combined with the FTA-FMECA method to control the reliability of a vehicle power system [37]. The test showed that this method provides a theoretical basis and technical support for the elimination of early faults in electromechanical products.