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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 investigate into the improvement strategies for lead time reduction of military aircraft major overhaul (enhance the overhaul task from present seven to nine-plus aircrafts as agreed to customer) for ABC Company.

This research has been conducted based on the available knowledge and extensive experience gained while working in the overhaul unit of the case organization for a long period of time. The research employs an integrated approach of multi-criteria decision method (in specific analytic hierarchy process (AHP)), theory of constraint (TOC) and simulation for M/M/1/K queuing environment for investigating the improvement strategies for lead time reduction in major overhaul of military aircraft. This has mainly included: Step 1: analysis of existing activity network using actual overhaul data; Step 2: ranking of constraint activities that most affects the lead time using AHP; Step 3: revised flow activity network using time buffers (TBs) concept of TOC; Step 4: mathematical model formulation for effective utilization of TB using single server finite queuing approach (M/M/1/K queuing environment); Step 5: discrete event simulation representing present overhaul conditions and revised overhaul conditions with different scenarios; and Step 6: sensitivity analysis and interpretation of results. The proposed methodology has been tested on an industrial case study dealing with an aircraft overhaul in India (namely ABC Company).

The proposed overhaul lead-time reduction plan points out the augmentation of resources in order to achieve more than 50 per cent reduction in lead time and waiting time under two scenarios – with overtime and without overtime.

An integrated approach proposed has so far been applicable to the specific aircrafts (Jaguar/Mirage/Kiran) of the ABC Company overhaul division. However, the particular methodology can be proved potentially useful and highly practical when applying to other aircraft types.

The results indicate several problems with the current overhaul strategies that need focused process improvements and a need for capacity augmentation for achieving the enhanced overhaul task of nine+ aircrafts per year with reduced overhaul lead time. The proposed approach also provides the maintenance planners with a platform for decision analysis and support often ignored the capacity augmentation.

The following extracts from the Plowden Committee's report on the aircraft industry cover the conclusions and summary of recommendations made by the Committee, and includes the reservation by Mr Aubrey Jones. Excerpts from some of the earlier chapters, discussing the environment in which the industry operates and its history, are also given, together with the first three chapters of Section 4] on ‘The Case for an Aircraft Industry’. The text is slightly abridged in some places. The full report, Command 2853, is obtainable at 10s. from Her Majesty's Stationery Office.

This paper reviews the growth of the Brazilian aircraft industry, and evaluates the strategic choices and government policies that have influenced its development. Brazil's goals of military independence, technological development and improvement of its balance of payments have influenced the development path chosen and the requirements for success. Brazil's attempts to overcome the barriers to achieving technological competence, cost competitiveness, market acceptance and financial sustainability are described. It is argued that the government has played a crucial role in providing financial resources and a protected domestic market, but that it has allowed the key enterprise, Embraer, to maintain an emphasis on commercial viability and international competitiveness. Embraer's emphasis on product niches where it has potential competitive advantages has been a key to its success. It is argued that a clear competitive strategy, based on a thorough analysis to the key success factors in the industry, is a vital link between government goals and support and international competitive success.

The growth in air mobility, rising fuel prices and ambitious targets in emission reduction are some of the driving factors behind research towards more efficient aircraft. The purpose of this paper is to assess the application of a blended wing body (BWB) aircraft configuration with turbo-electric distributed propulsion in the military sector and to highlight the potential benefits that could be achieved for long-range and heavy payload applications.

Mission performance has been simulated using a point-mass approach and an engine performance code (TURBOMATCH) for the propulsion system. Payload-range charts were created to compare the performance of a BWB aircraft with various different fuels against the existing Boeing 777-200LR as a baseline.

When using kerosene, an increase in payload of 42 per cent was achieved but the use of liquefied natural gas enabled a 50 per cent payload increase over a design range of 7,500 NM. When liquid hydrogen (LH2) is used, the range may be limited to about 3,000 NM by the volume available for this low-density fuel, but the payload at this range could be increased by 137 per cent to 127,000 kg.

The results presented to estimate the extent to which the efficiency of military operations could be improved by making fewer trips to transport high-density and irregular cargo items and indicate how well the proposed alternatives would compare with present military aircraft. There are no existing NATO aircraft with such extended payload and range capacities. This paper, therefore, explores the potential of BWB aircraft with turbo-electric distributed propulsion as effective military transports.

The purpose of this paper is to develop a stochastic detailed schedule for a preventive/scheduled/periodic maintenance program of a military aircraft, specifically a rotorcraft or helicopter.

The new model, entitled the military “periodic aviation maintenance stochastic schedule” (PAM-SS), develops a stochastic detailed schedule for a PUMA SA 330SM helicopter for the 50-h periodic inspection, using cyclic operation network (CYCLONE) and Monte Carlo simulation (MCS) techniques. The PAM-SS model identifies the different periodic inspection tasks of the maintenance schedule, allocates the resources required for each task, evaluates a stochastic duration of each inspection task, evaluates the probability of occurrence for each breakdown or repair, develops the CYCLONE model of the stochastic schedule and simulates the model using MCS.

The 50-h maintenance stochastic duration follows a normal probability distribution and has a mean value of 323 min and a standard deviation of 23.7 min. Also, the stochastic maintenance schedule lies between 299 and 306 min for a 99 per cent confidence level. Furthermore, except the pilot and the electrical team (approximately 90 per cent idle), all other teams are around 40 per cent idle. A sensitivity analysis is also performed and yielded that the PAM-SS model is not sensitive to the number of technicians in each team; however, it is highly sensitive to the probability of occurrence of the breakdowns/repairs.

The PAM-SS model is specifically developed for military rotorcrafts, to manage the different resources involved in the detailed planning and scheduling of the periodic/scheduled maintenance, mainly the 50-h inspection. It evaluates the resources utilization (idleness and queue), the stochastic maintenance duration and identifies backlogs and bottlenecks.

The PAM-SS tackles military aircraft planning and scheduling in a stochastic methodology, considering uncertainties in all inspection task durations and breakdown or repair durations. The PAM-SS, although developed for rotorcrafts can be further developed for any other type of military aircraft or any other scheduled maintenance program interval.

Accles & Pollock Ltd. of Oldbury, Worcestershire, a TI Steel Tube Division company, will be exhibiting a comprehensive range of precision steel tube and tubular products, including plain, annularly convoluted and thin wall tube, at Farnborough.

IN setting out to study the exhibits at a great international exhibition such as that recently held at Olympia, one is naturally inclined in the first place to walk round the exhibition as a whole, so as to form some general impressions before examining the individual stands in detail. In the same way it is proposed in this article to make a general review of the exhibition as a whole before embarking on detailed comments on particular items of interest which were to be found at the various stands. It is by no means an easy matter to analyse the general tendencies of design as demonstrated at the Exhibition for the principal reason that there is so little to go upon in the way of existing standards. No less than nine years have passed since the previous International Aero Exhibition at Olympia, and during that long period there has been no general exposition of British aircraft design. It is true that there has been a succession of International Aero Exhibitions in Paris and that last year, for the first time since the war, there was an International Aero Exhibition at Berlin, but British design has been very poorly represented at any of these or the several other exhibitions held on the Continent.

On show for the first time, a new and unique super lightweight headset to be known as the Minilite will be the main feature of the Amplivox Communications stand at the Paris Salon.