Special Issue "Civil and Military Airworthiness: Recent Developments and Challenges"

A special issue of Aerospace (ISSN 2226-4310).

Deadline for manuscript submissions: 30 November 2018

Special Issue Editor

Guest Editor
Dr. Kyriakos I. Kourousis

Senior Lecturer (Associate Professor)
School of Engineering, University of Limerick, Limerick, Ireland
Website | E-Mail
Interests: continuing airworthiness management; aircraft engineering, maintenance and technical support; aviation safety; defence engineering and support; engineering education and training

Special Issue Information

Dear Colleagues,

The “Civil and Military Airworthiness: Recent Developments and Challenges” Special Issue aims to cover a broad coverage of contemporary issues and research conducted in the fields of initial and continuing airworthiness, both in the civil and military aviation. This Special Issue offers the opportunity to academics, researchers and industry practitioners working in the broader airworthiness area to publish their original research and review articles.

Particular emphasis will be given on state-of-the art review works and theoretical, experimental, computational research and applied engineering work conducted on:

Initial Airworthiness

  • Aircraft and aeronautical components testing and certification;
  • Qualification and certification of new technologies, i.e., supersonic transport aircraft, electric and hybrid propulsion aircraft, etc.
  • Certification of systems specific to military aircraft;
  • Qualification and certification of additively manufactured metallic and non-metallic safe/non-safety critical aircraft parts;
  • Advanced testing and computational techniques for composite aircraft testing and certification;
  • Reliability engineering methodologies and practice in aircraft design and engineering changes;
  • Safety and risk assessment methodologies and practice in aircraft development;
  • Human factors’ considerations in aircraft design.

Continuing Airworthiness

  • Safety and risk assessment in aircraft flight and technical operations;
  • Reliability analysis of aircraft systems and components;
  • Continuing airworthiness management practice in civil and military aviation;
  • Development and optimization of aircraft maintenance programmes;
  • Development and optimization of military aircraft structural integrity (ASI) management programmes;
  • Effective and efficient inspection and sustainment techniques for composite aircraft;
  • Human factors in aircraft maintenance and operations;
  • Safety management effectiveness in flight and technical operations;
  • Quality management and optimization in aircraft maintenance organisations;
  • Aircraft technical and non-technical cost analysis and estimation techniques.

Dr. Kyriakos I. Kourousis
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Aerospace is an international peer-reviewed open access quarterly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 550 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Published Papers (8 papers)

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Research

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Open AccessArticle Crack Growth in a Range of Additively Manufactured Aerospace Structural Materials
Aerospace 2018, 5(4), 118; https://doi.org/10.3390/aerospace5040118
Received: 26 September 2018 / Revised: 25 October 2018 / Accepted: 2 November 2018 / Published: 9 November 2018
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Abstract
The aerospace industry is now beginning to adopt Additive Manufacturing (AM), both for new aircraft design and to help improve aircraft availability (aircraft sustainment). However, MIL-STD 1530 highlights that to certify airworthiness, the operational life of the airframe must be determined by a
[...] Read more.
The aerospace industry is now beginning to adopt Additive Manufacturing (AM), both for new aircraft design and to help improve aircraft availability (aircraft sustainment). However, MIL-STD 1530 highlights that to certify airworthiness, the operational life of the airframe must be determined by a damage tolerance analysis. MIL-STD 1530 also states that in this process, the role of testing is merely to validate or correct the analysis. Consequently, if AM-produced parts are to be used as load-carrying members, it is important that the d a / d N versus ΔK curves be determined and, if possible, a valid mathematical representation determined. The present paper demonstrates that for AM Ti-6Al-4V, AM 316L stainless steel, and AM AerMet 100 steel, the d a / d N versus ΔK curves can be represented reasonably well by the Hartman-Schijve variant of the NASGRO crack growth equation. It is also shown that the variability in the various AM d a / d N versus Δ K curves is captured reasonably well by using the curve determined for conventionally manufactured materials and allowing for changes in the threshold and the cyclic fracture toughness terms. Full article
(This article belongs to the Special Issue Civil and Military Airworthiness: Recent Developments and Challenges)
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Open AccessArticle Damage Localization in Composite Structures Using a Guided Waves Based Multi-Parameter Approach
Aerospace 2018, 5(4), 111; https://doi.org/10.3390/aerospace5040111
Received: 19 September 2018 / Revised: 15 October 2018 / Accepted: 16 October 2018 / Published: 19 October 2018
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Abstract
Aerospace vehicles are demanded to withstand harsh conditions with a low weight impact. Composites have been increasingly adopted to meet such performances but they are affected by sudden and barely visible failures when subjected to low velocity impacts. The design criteria and the
[...] Read more.
Aerospace vehicles are demanded to withstand harsh conditions with a low weight impact. Composites have been increasingly adopted to meet such performances but they are affected by sudden and barely visible failures when subjected to low velocity impacts. The design criteria and the maintenance tasks in a damage tolerant approach are unavoidably compromised. Structural Health Monitoring is expected to avoid typical accommodations employed during design and lifetime management by achieving a cost-effective and on condition maintenance. This paper describes the use of guided ultrasonic waves excited and sensed by permanently attached piezoelectric transducers for detection and localization of unforeseen and hidden flaws in composite structures. A composite stiffened structures designed for real scale components is investigated to test a multi-parameter detection technique capable of predicting different wave features affected by hidden failures to detect any possible change in the structure. Usually, propagation behavior is exploited to detect changes in the waveguide focusing on the analysis of an intrinsic feature of the propagating wave. Numerical simulations and measurements carried out on a real-scale aircraft structure demonstrate that increasing the observed characteristics improves the result making efficient the diagnosis. Furthermore, it is shown that accounting a multi-parameter analysis of ultrasonic data enhances the localization reliability making use of the same reconstruction algorithm with data fusion approach while facing with different kind of damages. Full article
(This article belongs to the Special Issue Civil and Military Airworthiness: Recent Developments and Challenges)
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Open AccessArticle The Development of an Ordinary Least Squares Parametric Model to Estimate the Cost Per Flying Hour of ‘Unknown’ Aircraft Types and a Comparative Application
Aerospace 2018, 5(4), 104; https://doi.org/10.3390/aerospace5040104
Received: 19 August 2018 / Revised: 20 September 2018 / Accepted: 29 September 2018 / Published: 3 October 2018
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Abstract
The development of a parametric model for the variable portion of the Cost Per Flying Hour (CPFH) of an ‘unknown’ aircraft platform and its application to diverse types of fixed and rotary wing aircraft development programs (F-35A, Su-57, Dassault Rafale, T-X candidates, AW189,
[...] Read more.
The development of a parametric model for the variable portion of the Cost Per Flying Hour (CPFH) of an ‘unknown’ aircraft platform and its application to diverse types of fixed and rotary wing aircraft development programs (F-35A, Su-57, Dassault Rafale, T-X candidates, AW189, Airbus RACER among others) is presented. The novelty of this paper lies in the utilization of a diverse sample of aircraft types, aiming to obtain a ‘universal’ Cost Estimating Relationship (CER) applicable to a wide range of platforms. Moreover, the model does not produce absolute cost figures but rather analogy ratios versus the F-16’s CPFH, broadening the model’s applicability. The model will enable an analyst to carry out timely and reliable Operational and Support (O&S) cost estimates for a wide range of ‘unknown’ aircraft platforms at their early stages of conceptual design, despite the lack of actual data from the utilization and support life cycle stages. The statistical analysis is based on Ordinary Least Squares (OLS) regression, conducted with R software (v5.3.1, released on 2 July 2018). The model’s output is validated against officially published CPFH data of several existing ‘mature’ aircraft platforms, including one of the most prolific fighter jet types all over the world, the F-16C/D, which is also used as a reference to compare CPFH estimates of various next generation aircraft platforms. Actual CPFH data of the Hellenic Air Force (HAF) have been used to develop the parametric model, the application of which is expected to significantly inform high level decision making regarding aircraft procurement, budgeting and future force structure planning, including decisions related to large scale aircraft modifications and upgrades. Full article
(This article belongs to the Special Issue Civil and Military Airworthiness: Recent Developments and Challenges)
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Open AccessArticle EASA’s “Open” Category for Military UAS: Opportunities and Limitations in the Field of Airworthiness
Received: 31 May 2018 / Revised: 22 June 2018 / Accepted: 25 June 2018 / Published: 1 July 2018
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Abstract
The European Aviation Safety Agency (EASA) plans to establish a sole risk-based set of regulations for drones to grant access to European airspace, thus opening a multibillion-euro market. One part of this new regulation set is the so-called “open” category, imposing only a
[...] Read more.
The European Aviation Safety Agency (EASA) plans to establish a sole risk-based set of regulations for drones to grant access to European airspace, thus opening a multibillion-euro market. One part of this new regulation set is the so-called “open” category, imposing only a minimum set of regulations. The EASA’s approach presents a strong converse to traditional and prescriptive airworthiness regulations. For decades, unmanned aircraft systems (UAS) have been state-of-the-art assets in military forces. Aiming at the fulfilment of complex missions in extreme environments, in different theatres of operation, and with different partners, military UAS need to be reliable, safe, and interoperable. Therefore, NATO established internationally accepted airworthiness standards. However, these standards might be too severe to be adhered to by small, commercial, off-the-shelf UAS in the up-to-25 kg category, preventing the military from benefiting from the now fast-growing civil drone market. Based on a sound literature review, the paper presents the EASA’s upcoming regulations for civil UAS and discusses if they are applicable to military UAS. Possible opportunities, challenges, and limitations of applying the approach for the military are shown. Full article
(This article belongs to the Special Issue Civil and Military Airworthiness: Recent Developments and Challenges)
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Open AccessArticle Use of Cost-Adjusted Importance Measures for Aircraft System Maintenance Optimization
Received: 28 May 2018 / Revised: 20 June 2018 / Accepted: 21 June 2018 / Published: 24 June 2018
Cited by 2 | PDF Full-text (2133 KB) | HTML Full-text | XML Full-text
Abstract
The development of an aircraft maintenance planning optimization tool and its application to an aircraft component is presented. Various reliability concepts and approaches have been analyzed, together with objective criteria which can be used to optimize the maintenance planning of an aircraft system,
[...] Read more.
The development of an aircraft maintenance planning optimization tool and its application to an aircraft component is presented. Various reliability concepts and approaches have been analyzed, together with objective criteria which can be used to optimize the maintenance planning of an aircraft system, subsystem or component. Wolfram® Mathematica v10.3 9 (Witney, UK) has been used to develop the novel optimization tool, the application of which is expected to yield significant benefits in selecting the most appropriate maintenance intervention based on objective criteria, in estimating the probability of nonscheduled maintenance and in estimating the required number of spare components for both scheduled and nonscheduled maintenance. As such, the results of the application of the tool can be used to assist the risk planning process for future system malfunctions, providing safe projections to facilitate the supply chain of the end user of the system, resulting in higher aircraft fleet operational availability. Full article
(This article belongs to the Special Issue Civil and Military Airworthiness: Recent Developments and Challenges)
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Open AccessArticle Differences in Risk Perception Factors and Behaviours amongst and within Professionals and Trainees in the Aviation Engineering Domain
Received: 5 April 2018 / Revised: 21 May 2018 / Accepted: 4 June 2018 / Published: 10 June 2018
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Abstract
In the aviation sector, the variability in the appreciation of safety risk perception factors and responses to risk behaviours has not been sufficiently studied for engineers and technicians. Through a questionnaire survey, this study investigated differences amongst professionals and trainees across eleven risk
[...] Read more.
In the aviation sector, the variability in the appreciation of safety risk perception factors and responses to risk behaviours has not been sufficiently studied for engineers and technicians. Through a questionnaire survey, this study investigated differences amongst professionals and trainees across eleven risk perception factors and five indicative risk behaviour scenarios. The findings indicated significant differences between the two groups in four factors and three scenarios as well as within groups. Moreover, age, years of work and study and educational level were other factors accounting for such differences within each group of professionals and trainees. The results showing these significant differences are aligned with relevant research about pilots and indicate that the appreciation of risk perception factors by aviation engineers and the development of their risk behaviours deserves more attention. Our findings cannot be generalised due to the small sample and its distribution across the demographic variables. However, the results of this study suggest the need tailoring risk communication and training to address the different degrees to which influences of risk perception factors are comprehended, and risk behaviours emerge in aviation engineering trainees and professionals. Further research could focus on the development of a respective uniform framework and tool for the specific workforce group and could administer surveys to more extensive and more representative samples by including open-ended questions and broader social, organisational and systemic factors. Full article
(This article belongs to the Special Issue Civil and Military Airworthiness: Recent Developments and Challenges)

Review

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Open AccessReview The Regulatory Framework for Safety Management Systems in Airworthiness Organisations
Aerospace 2018, 5(4), 117; https://doi.org/10.3390/aerospace5040117
Received: 31 August 2018 / Revised: 23 October 2018 / Accepted: 1 November 2018 / Published: 7 November 2018
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Abstract
In recent years, a growing emphasis on safety has driven various industries, both in manufacturing and service, to implement a Safety Management System (SMS) in their organisations. SMSs have also been widely implemented in aviation due to both regulatory requirements and voluntary implementation
[...] Read more.
In recent years, a growing emphasis on safety has driven various industries, both in manufacturing and service, to implement a Safety Management System (SMS) in their organisations. SMSs have also been widely implemented in aviation due to both regulatory requirements and voluntary implementation with the aim of decreasing incidents and accidents whilst reducing inefficiencies and costs stemming from the repercussions of safety failures. The aviation industry involves various players for the provision of services ranging from airline operations, maintenance, aerodrome operations, air traffic services, aircraft and component design, manufacturing, and training. Not all organisations in the aviation industry have implemented SMSs. Furthermore, SMS is currently not regulated for all aviation organisations. Whilst technology has played a key role in driving down the number of accidents and incidents in aviation, the growth in air traffic demands having programs in place to further drive down accident rates. In this context, this article provides an investigation to the regulatory framework for the implementation of SMSs in aviation, including the requirements stipulated by the International Civil Aviation Organisation (ICAO) and the status of SMS regulation of key National Aviation Authorities (NAA) and Military Aviation Authorities (MAA), with a focus on organisations involved in airworthiness including initial and continuing airworthiness. This article also investigates the challenges of implementing SMSs in organisations involved in Airworthiness, as well as the benefits that could be gained by service providers as well as NAA’s or MAA’s through SMSs. Full article
(This article belongs to the Special Issue Civil and Military Airworthiness: Recent Developments and Challenges)
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Open AccessReview Cost-Effectiveness of Structural Health Monitoring in Fuselage Maintenance of the Civil Aviation Industry
Received: 6 June 2018 / Revised: 21 July 2018 / Accepted: 7 August 2018 / Published: 13 August 2018
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Abstract
Although structural health monitoring (SHM) technologies using sensors have dramatically been developed recently, their capability should be evaluated from the perspective of the maintenance industry. As a first step toward utilizing sensors, the objective of the paper is to investigate the possibility of
[...] Read more.
Although structural health monitoring (SHM) technologies using sensors have dramatically been developed recently, their capability should be evaluated from the perspective of the maintenance industry. As a first step toward utilizing sensors, the objective of the paper is to investigate the possibility of using sensors for inspecting the entire fuselage during C-check. First, we reviewed various sensors for their detection range, detectable damage size, and installed weight, which revealed that the piezoelectric wafer active sensor (PWAS) is the most promising sensor for aircraft SHM. Second, we performed a case study of inspecting the fuselage of Boeing-737NG using PWAS. To maintain the same detecting capability of manual inspection in C-check, we estimated the total number of sensors required. It turned out that utilizing sensors can reduce the maintenance downtime and thus, maintenance cost. However, even with a very conservative estimate, the lifetime cost was significantly increased due to the weight of sensor systems. The cost due to the weight increase was an order of magnitude higher than the cost saved by using SHM. We found that a large number of sensors were required to detect damage at unknown locations, which was the main cause of the weight increase. We concluded that to make SHM cost-effective, it would be necessary either to improve the current sensor technologies so that a less number of sensors are used or to modify the aircraft design concept for SHM. Full article
(This article belongs to the Special Issue Civil and Military Airworthiness: Recent Developments and Challenges)
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