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In this study, a multi-criteria decision-making (MCDM) approach for evaluating airworthiness factors were presented. The purpose of this study is to develop an acceptable rationale for operational activities in civil and military aviation and for design, production and maintenance activities in the aviation industry that can be used in-flight safety programs and evaluations.

In aviation, while the initial and continuing airworthiness of aircraft is related to technical airworthiness, identifying and minimizing risks for avoiding losses and damages are related to operational airworthiness. Thus, the airworthiness factors in civil and military aviation were evaluated under these two categories as the technical and operational airworthiness factors by the analytic hierarchy process and analytic network process. Three technical and five operational airworthiness criteria for civil aviation, three technical and nine operational airworthiness criteria for military aviation were defined, evaluated, prioritized and compared in terms of flight safety.

The most important technical factor is the “airworthiness status of the aircraft” both in civil (81.9%) and military (77.6%) aviation, which means that aircraft should initially be designed for safety. The most significant operational factors are the “air traffic control system” in civil (30.9%) and “threat” in the military (26.6%) aviation. The differences within factor weights may stem from the design requirements and acceptable safety levels (frequency of occurrences 1 in 10⁷ in military and 1 in 10⁹ in civil aircraft design) of civil and military aircraft with the mission achievement requirements in civil and military aviation operations. The damage acceptance criteria for civil and military aircraft are different. The operation risks are accepted in the military and acceptance of specific tasks and the risk levels can vary with aircraft purpose and type.

This study provides an acceptable rationale for safety programs and evaluations in aviation activities. The results of this study can be used in real-world airworthiness applications and safety management by the aviation industry and furthermore, critical factor weights should be considered both in civil and military aviation operations and flights. The safety levels of airlines with respect to our airworthiness factor weights or the safety level of military operations can be computed.

This is the first study considering technical and operational airworthiness factors as an MCDM problem. Originality and value of this paper are defining critical airworthiness factors for civil and military aviation, ranking these factors, revealing the most important ones and using MCDM methods for the evaluations of airworthiness factors for the first time. In civil aviation flight safety is the basic tenet of airworthiness activities in risk analysis, on the other hand in military aviation high levels of risks are to be avoided in peace training or operational tasks. However, even high risks have to be accepted during the war, if the operational requirements impose, as mission achievement is vital. The paper is one of a kind on airworthiness evaluations for flight safety.

The purpose of this paper is to introduce the multidisciplinary design optimization method using approximation model for the aircraft engine fan blade based on the airworthiness compliance such as stress, vibration, and bird impact.

Firstly, the airworthiness analysis of the typical fan blade was carried out based on the numerical simulation. Secondly, the design of experiment (DOE) was utilized to construct the approximation model of the fan blade. Finally, the airworthiness optimization of fan blade was carried out based on Kriging approximation model.

The numerical simulation result shows that the analysis method can show the airworthiness compliance in the design stage. And the optimization result shows that structure, bird impact and vibration characteristics improve obviously, satisfying the constraints conditions of optimization.

The multidisciplinary design optimization method of fan blade based on the airworthiness and approximation model is presented and achieved.

The Annual Conference held in London and sponsored by British Caledonian Airways attracted delegates from 18 countries covered many aspects of airworthiness.

To reduce the flammability exposure assessment time and meet the requirements of airworthiness regulations of transport aircraft, inerting system has become the standard configuration of modern civil aircraft. Therefore, airworthiness regulations put forward definite quantitative index requirements for the safety of inerting system, and to obtain the quantitative data of the safety of inerting system, it is necessary to solve the calculation method. As one of the quantitative/qualitative evaluation techniques for system safety, fault tree analysis is recognized by international airworthiness organizations and national airworthiness certification agencies. When fault tree analysis technology is applied to quantitative analysis of the safety of inerted system, there are still some problems, such as heavy margin of constructing fault tree, great difficulty, high requirement for analysts and poor accuracy of solving when there are too many minimum cut sets. However, based on tens of thousands of flight simulation tests, Monte Carlo random number generation method can solve this problem.

In this paper, the fault tree of airborne inerting system is established, and the top event is airborne inerting system losing air separation function. Monte Carlo method based on random number generation is used to carry out system security analysis. The reliability of this method is verified.

The static fault tree analysis method based on Monte Carlo random number generation can not only solve the problem of quantitative analysis of inerting system, but can also avoid the defects of complicated solution and inaccurate solution caused by the large number of minimum cut sets, and its calculation results have good reliability.

The research results of this paper can be used as supporting evidence for airworthiness compliance of airborne inerting system.

The research results of this paper can provide practical guidance for the current civil airworthiness certification work.

In my introductory article, “Airworthiness — A Systems Approach”, last March, I expressed the hope that eminent engineers from all the disciplines and activities on which “total airworthiness” (my phrase) depends, would be persuaded by Aircraft Engineering to contribute articles on their own specialisations.

Major changes of an aircraft configuration are conducted during the early design stage. It is important to include the airworthiness regulations at this stage while there is extensive freedom for designing. The purpose of this paper is to introduce an efficient design framework that integrates airworthiness guidelines and documentation at the early design stage.

A new design and optimization process is proposed that logically includes the airworthiness regulations as design parameters and constraints by constructing a certification database. The design framework comprises requirements analysis, preliminary sizing, conceptual design synthesis and loads analysis. A design certification relation table (DCRT) describes the legal regulations in terms of parameters and values suitable for use in design optimization.

The developed framework has been validated and demonstrated for the design of a Federal Aviation Regulations (FAR) 23 four-seater small aircraft. The validation results show an acceptable level of accuracy to be applied during the early design stage. The total mass minimization problem has been successfully solved while satisfying all the design requirements and certification constraints specified in the DCRT. Moreover, successful compliance with FAR 23 subpart C is demonstrated. The proposed method is a useful tool for design optimization and compliance verifications during the early stages of aircraft development.

The new certification database proposed in this research makes it simpler for engineers to access a large amount of legal documentation related to airworthiness regulations and provides a link between the regulation text and actual design parameters and their bounds.

The proposed design optimization framework integrates the certification database that is built of several types of legal documents such as regulations, advisory circulars and standards. The Engineering Requirements and Guide summarizes all the documents and design requirements into a single document. The DCRT is created as a summary table that indicates the design parameters affected by a given regulation(s), the design stage at which the parameter can be evaluated and its value bounds. The introduction of the certification database into the design optimization framework significantly reduces the engineer’s load related for airworthiness regulations.

This article is written by Mr. Major at the invitation of the publishers of AIRCRAFT ENGINEERING as an introduction to the series that is being published during 1980, (as was said in the Comment in the January issue), on the important subject of Airworthiness. Mr. Major says “My comments are not intended to be an official expression of views of the Society of which I am President, and they are based on experience in civil air transport covering technical development, aircraft maintenance and ground operations and, in the aircraft manufacturing industry, covering structural and detail design, production and after‐sales liaison with military users. This fairly diverse experience and some of the events which have occurred in the course of acquiring it, have led me to the view that many (perhaps most) of the airworthiness shortcomings that occur are due to the ‘gulfs’ which develop between specializations, or to the lack of communication (in the widest sense — and both ways) between the elements contributing to ‘total’ airworthiness.”

The International Federation of Airworthiness in an issue of its introductory brochure is presenting a new image, that of a link in the Airworthiness Chain.

The purpose of this paper is to discuss European Aviation Safety Agency’s (EASA’s) Prototype Regulation on Unmanned Aircraft Operation and introduce the tool Operational Risk Considerations for Unmanned Aircraft Systems (O.R.C.U.S.). In contrast to existing airworthiness regulations for civil manned aircraft, EASA’s approach is focussed on flight operations and not aircraft, a significant change for the domain of civil airworthiness.

O.R.C.U.S. is a software risk analysis tool developed by the corresponding author. It encompasses all relevant factors for flight operations of light Unmanned Aircraft Systems (UAS) above populated areas in Germany. The tool generates predictions of possible fatalities in the event of a light Unmanned Aircraft crash through the use of validated statistics and considering the time and location of a mission. An example mission, including a discussion of the results, is provided to demonstrate and discuss the capabilities of O.R.C.U.S.

EASA’s Prototype Regulation on Unmanned Aircraft Operation makes a sound risk assessment of UAS flight operations indispensable. O.R.C.U.S. is able to increase risk awareness for operators and airworthiness authorities even if only less to none information about the UAS is available, supporting the possible approval of such an operation.

In this paper, O.R.C.U.S. is presented for the first time. O.R.C.U.S. can provide risk estimations for UAS operations in Germany, even if only minimum information about the UAS is available. In contrast to other tools, O.R.C.U.S. offers a unique risk prediction by combining aspects of the flying Unmanned Aircraft as well as the overflown area.

IF the history of air transport is traced back we find that superimposed on a steady rate of development, there have been several important milestones standing out as major jumps in technological progress. The first cabin airliner‐the first monoplane‐the first pressure cabin‐the first turbine‐the first jet and now the first supersonic transport.