Aviation Maintenance Management Theory and Practices

Aviation Maintenance Management Theory & Practices

Aeronautics is considered to be the most secured and fastest mode of journey. But the frequent air accidents and resulting consequences reduce our reliance on the mode. Human flaws are acknowledged to be very critical in diverse fields like medicine, mining, shipping so also aviation. Irrespective of the fact that the role human component is widely acknowledged in the cockpit, its contribution in sphere of aircraft maintenance has been ignored to a great extent. (Special Investigation Reports: Aircraft Maintenance Safety Survey) The first ever air accident as a consequence of manufacturing and designing error was associated with lcarus while many held the mistakes committed by pilot as responsible for the same. The faulty maintenance and irregular maintenance is considered to be a major cause of most of the air disasters presently. The accident of Aloha Airlines in Hawaii during 1988 occurred as a result of isolation of fuselage of the plane at the floor line while flying. (Aircraft maintenance management)

Traditionally, the analysis of the actions and inactions of operational staff in retrospect is resorted to in order to evaluate the influence of human performance with regard to safety. While analyzing in such lines it is customary to refer to normally established standards and prevailing conventions about the facts constituting safe and unsafe acts so as to find out the acts and behaviors that would have been successfully avoided the occurrence of the incident. However, the conclusions so drawn are normally based on limited facts with regard to the processes that results in insufficient conclusions. Moreover, when assessing the incidents the investigators could know that the activities portrayed by the operational staff were bad or inappropriate since the negative outcomes are in record. The traditional safety paradigm prescribes that safety is the first in aviation. Consequently, human activities and decision making activities in aviation functions are regarded as cent percent safety oriented. However, this does not hold good. More realistically, human behaviors and decision making in relation to the operational fields are considered to be a balance between the production influenced activities and decisions and safety oriented behaviors and decisions. The optimization of the behavior to attain the production requisites may not be fully compatible with the optimum behaviors to attain the theoretical safety requirements. (Human error in aviation maintenance: the years to come)

As per the survey conducted about the Boeings about 12% of major aircraft accidents are attributed to the poor maintenance and about 50% of delays in flight timings in the U.S. are due maintenance snags. The Australian Transport Safety Bureau - ATSB in 1998 circulated a safety survey to all licensed aircraft maintenance engineers in Australia that is considered to be the first ever survey conducted in the World. The survey collected incident reports as well as reports on minor errors and shortcuts applying the technique pioneered by road safety researchers in the UK. The survey concentrated on collection of common occurrence of such events in relation to one another in addition to the event frequency information. Most of the errors have been reported to be 'near misses'. However, accumulation of such information gathers to have grave consequences. The findings of ATSB are not specific to Australia alone but can be equally applicable to the safety agencies all over the world. (Special Investigation Reports: Aircraft Maintenance Safety Survey)

The Bureau previously published the findings of the survey in Asia Pacific Air Safety articles with a number of recommendation such as, the necessity for refresher training for aircraft maintenance engineers, the necessity to remove obstacles that dissuade aircraft maintenance engineers from reporting incidents; the necessity for fatigue management programs; training of human resources for management and engineers; rationalize the effect of simultaneous disturbance of multiple of parallel systems, like both engines or twin engine aircraft. Later in 2000 the ATSB supplemented and published in Flight Safety Australia and advised the aircraft maintenance engineers in respect of the memory lapses, pressure, and fatigue and coordination problems. (Special Investigation Reports: Aircraft Maintenance Safety Survey)

In consequence with the fast growing technical attributes of physical assets, dramatic evolution have been seen in the field of the maintenance management over the last three decades. The necessity for a new type of asset management was first felt by the commercial aviation industry in 1970, when the traditional maintenance techniques were acknowledged to be neither cost effective nor safe. The foundation for modern practices was laid with their inter-disciplinary collaborative activities. The major aircraft manufactures like the FAA and major U.S. airlines, during 1970 united to generate a sequence of reports, recommendations and revisions in relation to maintenance activities in respect of complex systems of modern physical assets. The Federal Government commissioned their findings under the heading of Reliability Centered Maintenance and became the source of the modern Reliance Centered Management practice. Ever since the origin of Reliability Centered Maintenance innovative ideas, enhanced flexibility, and new maintenance techniques are regularly been incorporated and the modern maintenance management systems have been evolved with further refinement. (The History of Modern Maintenance Management Systems)

The Reliability Centered Maintenance-based maintenance management systems are in application presently in varied industries through out the world. Reliance Centered Management is felt to be incredible customized having its strength lying in the center of Reliance Centered Management ideology. The Reliance Centered Management practitioners seem to deploy maintenance management systems that target the specific needs and consequences of any potential failure state of affairs. However, Reliance Centered Management is not viewed as a mere improvement of the traditional maintenance strategies. It is considered almost a complete turnaround of them and actually reveals the magnitude that the function of assets has varied in the business environment. Before the analysis made during 1970s there prevailed a maintenance model for the failure of tools and equipments thereby enabling the asset managers to treat all the assets equally. Ever since the origin of Reliance Centered Management and modern maintenance management systems, the amount of accepted outline for conditional potential of failure increasing to six normally which turned around the basic ideology behind the old failure pattern model. (The History of Modern Maintenance Management Systems)

Traditionally, the task of aircraft maintenance and inspections were primarily regulated by the manufacturer of the aircraft or aeronautical products. This strategy was adequately serving the industry for quite a long a time. However, the users who are desirous of doing the things differently find this strategy to be more restrictive. The traditional system envisaged the lumping together of everyone with out any regard to operation experience, environment and geographical location. This evidently resulted in enhanced operational costs for those companies not prone to such maintenance problems or alternatively to those who were not in a position to accept proactive maintenance techniques. Many controlling agencies around the globe, taking into consideration such problems and being confronted with the challenges exerted by aviation maintenance industries sought for other inspection strategies or methods as a basis for approving inspection programs. In Canada, this gave rise to a basic distortion in the late 1970s, so as to provide the individual operators adequate scope to design their own programs. Presently, all the operators of commercial aircraft in Canada is required to furnish a maintenance schedule in respect of each of the aircraft type in their fleet, for authentication by the regulatory authorities. (Maintenance Schedules - A Key to Success)

This is considered as a regulatory requirement of the Aircraft Requirements, CAR 605. In this respect the proposals are to be submitted in consonance with the guidelines and principles framed in the Aircraft Equipment and Maintenance Standards, STD 625, Appendix D. These are mainly based on the prescriptions of the manufacturers or on the processes prescribed by Maintenance Review Board. These are subjected to the principles framed under STD 625, Appendix B, in case of small aircraft. The maintenance schedule commonly termed as Inspection Program Approval is considered as a prime regulatory tool by which the Transport Canada allows an air operator to regulate its own inspection program under certain conditions. The procedure is proven to be quite effective and approval to the individual programs is accorded taking into consideration proven performance data normally referring to the MRB Report or the Maintenance Planning Document - MPD for the product and are also inclusive of the own applicable operational experience of the company.

The Transport Canada communicates the key aspects of its approval. Even though the approved maintenance schedule does not in itself incorporate the detailed maintenance or inspection task elements yet acts as a facilitating document. Thus the basic principles of the program approval of the operator remain the same while the detailed job-associated components are regulated separately by the respective manuals or work cards. It has been stipulated that the modifications affecting the principal areas of the maintenance schedule is to be duly approved by the Transport Canada irrespective the choice of the programs. The operator is at its liberty within this structure to rework or amend the task-related details within the approved stands in consonance with the operational requirements. Irrespective of the fact that the maintenance schedule is normally approved by the Transport Canada independently, it still constitutes a part of the larger maintenance strategy and is to be detected as such in the Maintenance Control Manual of the air operator. (Maintenance Schedules - A Key to Success)

Irrespective of the fact the maintenance schedules may be based on the program of another operator when submitted to Transport Canada for approval, however once approved these maintenance schedules are not transferable. Even though there are some similarities, the variations in operational experience, maintenance management systems, reliability programs and other necessary supportive process distinguish the two approvals. Many benefits have been visualized in designing a program to cater to the individual operational requirements, in addition to greater economy and with no diminution to the aviation safety. The operators having large fleets finds it very cost effective than simply depending upon the hard time-based programs. The company finds itself to be in a good position to customize its inspection frequencies and maintenance tasks so as to satisfy its intended operational requirements. The concept of maintenance schedules is however not regarded as new, however, seen as suitable to the present environment where leased aircraft move from one fleet operator program to another instantly.

The prorating concept is also applied conveniently to the components. There is a stipulation that the components can be used for up to 100 hours without actually adhering to the prorating formula. This provision is seen to have benefited the operator in terms of saving of time and money. Invariably, the operators that find it difficult to adopt strong analysis or reliability programs to adhere to the maintenance activities, seems to gain more autonomy from the regulatory regime. The uniqueness of the approved maintenance schedule applied in combination with other regulatory program options like inspection tolerance controls, Minimum Equipment Lists and in-house Ferry Flight Authority control, the unique aspects of an approved maintenance schedule can entail the operator with enhanced independent program regulation. It is significant to become accustomed to the criteria administering the maintenance schedule approval process as the benefits entailed from a dynamic program will be rapidly acknowledged by an improved bottom line. (Maintenance Schedules - A Key to Success)

During the past years the concept of maintenance management has attracted growing attention of academics, industrial practitioners and consultants who devised a number of theories associated with it. This gave rise to a state of confusion and conflict under the terminology of 'Maintenance Theory Jungle'. The concept of 'Management Theory Jungle', depicting the conflicting approaches to management theory was first introduced to the students and practitioners of the management by Harold Koontz during 1961. The similarities between the elements of 'management jungle' devised by the Koontz and the present status of maintenance management theory have been visualized. The original 'Management Theory Jungle' was proposed amidst a state of affairs where the development of the management theory has grown at least for two decades. The state of affairs for this was characterized by the systematic analysis of the management as a product of a period of 20 years; prior to that no significant contribution had been visualized; the management theory were to concentrate on the observations of the experienced practitioners prior to that; during the subsequent two decades a number of theories flooded the management scenario resulting in great differences of opinions and confusions. (The Maintenance Theory Jungle)

Koontz visualized the 'Management Theory Jungle' as a symbol of the 'unsophisticated adolescence' of the management theory during the period. It has further been perceived that the appearance of the management theory jungle constituted the recent curiosity in the subject matter by a diverse range of scientists, scholars and enterprise managers. This is found to have resulted in the devising and development of management theory as being both challenging and being profitable. The frustration of great social potential for improved management as a result of the confused and destructive jungle warfare has been seen by the conflicting jungle warfare. In line with this similar maintenance theory jungle is perceived to have existed in respect of the maintenance theories giving rise to the concept of the maintenance theory jungle. The maintenance management theories have been observed by Visser to be only of recent origin. Irrespective of the fact that it was applied during the post Second World War periods, it has been developed to be a separate academic discipline only during 1980. A few of the earliest writings on maintenance management were evident prior to 1975.

Anderson was able to find out about 110 publications associated with maintenance and maintenance management, however, only a few out of those dates back prior to 1975. The writings of Sack in 1963 and Newborough in 1967 were considered to be illustrations of early writings in maintenance. The era after 1975 was regarded as most productive in respect of the publications with regard to maintenance management. This era initiated with the publications by Mann and Heitzelman during 1976 and Kelly and Harris in 1978. However, more than 95% of the identified publications in maintenance management are observed to have devised only after 1975 that stands as a testimony to the conclusion that the development of the maintenance management theories as an academic discipline have only developed within the last two decades. In between the earliest documentation approach and contemporary maintenance management there emerged enormous associated and unassociated ideas. (The Maintenance Theory Jungle)

The advocates of maintenance theories have affirmed that there existed a large body of approaches and 'approachers' to the maintenance theory. The number of literatures of maintenance management seems to have been compounded in every five-year period from 1976. The prevailing models were reformulated and renamed and new theories were generated from the existing ones in absence of a universally agreeable approach to the maintenance management which led to confusion. All such contribute to conclude existence of a similar state of affairs for emergence of the Maintenance Theory Jungle in line with the Management Theory Jungle observed by Koontz as earlier as 1963. On the basis of the categories of major theories prevalent six schools of thought associated with maintenance management can conveniently be traced out. Those are Management Process School, Empirical School, Human Behavior School, Social System School, Decision Theory School, and Mathematical School.

The Process School of thought represents the study of maintenance as a process or sequential occurrence of the process. The strategy of the maintenance process school is to become aware of the purpose function and philosophy of different attributes of management and to document them for further analysis. The strategy is to prescribe standards for the practice of maintenance management those involve the stages of the auditing the maintenance process, teaching the fundamentals of maintenance management theory and conducting research and development in the sphere of maintenance management processes. The process school emphasizes on the generic or non-industry specific attributes of the maintenance. The process school of thought is associated with detection of all the attributes of management of maintenance. In consequence to this the outcomes are taken to be of universally applicable in nature. The process school employs other techniques as instruments for attaining the results of the maintenance management. The Mathematical School is associated with identifying quantitative solutions to the problems of maintenance management. The strategy involves defining the maintenance problem in logical terms and then represents the same as a mathematical function. The maintenance problems are solved as a solution to the mathematical functions. The quantitative solutions in this ideology are normally aimed at an economic optimization of the maintenance effort. (The Maintenance Theory Jungle)

To illustrate the works by Jardine that prescribes for the standards of replacement of equipment and decision making after inspection, maximizing organizational structures, reliability and scheduling and sequence activities of decisions taken is grouped under this category. The strategies involved in mathematical school are further developed to constitute the computerized maintenance management solutions. The Reliability School embodies a multitude of approaches that indicate the processes for innovating maintenance approaches on the basis of the analysis of the maintenance resulting in items of a facility. Unlike the ideology of Mathematical school the reliability school of thought is less concerned with the application of the data and statistics relating to failures however, more concerned with priori analysis and with mandatory or economic failure avoidance relying on the perceived failure consequences. The concept of Reliability Centered Maintenance is a better example of the thoughts of the reliability school. The Failure Modes and Effect Analysis - FMEA is also another outcome of this school.

The concepts of failure modes and effect analysis give rise to infusion of the concept of criticality to FMEA to form the model of Failure Modes, Effects and Criticality Analysis - FMECA on the basis of blending of reliability and severity. FMECA was successfully be developed by NASA for Apollo Space Programs in the 1960s. Presently it has been applied to detect the modes of failure for equipment in the operations phase of operating plant and also to devise maintenance approaches essential to predict the onset of failure or combat the impact of the failure. Application of the 'Fuzzy Logic' is found presently in greater intensity to analyze the failure criticality. Many theories have been devised with slight variations of the RCM and FMEA ideology. The earliest reference to the Quality School of management seems to have developed from Japan in 1940. In line with the thoughts of Deming, Ohno developed systems for Toyota so as to attain the highest quality product and to avoid wastes. Such systems entailed the basics for the origination of the quality maintenance systems those were initially targeted at the deployment of the quality tools to the maintenance related problems. The quality school of maintenance envisages Total Productive Maintenance - TPM that refers to the productive maintenance resorted to by all employees by means of small group activities. It is the duty of the machine operator to maintain the machine along with operating, in TPM approach. (The Maintenance Theory Jungle)

The other attributes of the TPM philosophy is based on team based approaches to solve problems to avoid significant losses and also to avoid wastes in the process. The application of the TPM concept is seen in many of the contemporary approaches having similar philosophies. The Condition-Based School emphasizes on the condition-based maintenance that involves reference to the monitoring of the condition, predictive maintenance or just in time maintenance. The school is associated with the identifying and measuring of the parameters that is used to find out or predict the prevalence of failure. This is applied to rectify the condition before the failure would result in. This school backs a wide range of techniques. The techniques starts from simple elements of tangible look, listen, smell and touch and extend to the complex technical and specialized procedures like oil analysis, vibration analysis and thermography. The ideology also advocates the matters of fault detection and diagnosis. (The Maintenance Theory Jungle)