W. van Rijn MSc


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The impact of a new maintenance approach on the RNLAF Apache maintenance organization

The AH-64D is the world’s most advanced multi role armed helicopter and represents a major advancement in war fighting capability and will provide commanders an unprecedented tactical advantage on the modern battlefield. The Apache’s ability to perform all RNLAF missions without reconfiguration is unmatched by any armed helicopter in production or under development. During recent years the initial Operational Tempo, the expected amount of flying hours per main weapons system per year, has changed because of the change in operations. In 2006 the Apache was sent to Afghanistan for home nation support for a period of 4 years, until mid 2010.

The Aim of this dissertation is to provide information on the usage of the Apache AH-64D, the effect of the introduction of Condition Based Maintenance (CBM) on the Apache AH-64D maintenance organization, and ways to optimize the design and representation of the maintenance plan as a contribution to the maintenance organization. The objectives of this dissertation are to review the existing knowledge of the usage of the Apache, describe situations or problems in relation to CBM, analyze the usability of an existing system like the Health an Usage Monitoring System, and usability of the Modernized Signal Processing Unit (MSPU) in relation to CBM. In order to achieve the aim and objectives of this research, it is important to understand what knowledge is necessary. For this purpose a research question was formulated.

In what way the change in the maintenance plan affect the maintenance organization in order to achieve maximum maintenance effectiveness of the Apache helicopter?

The current maintenance plans are based on flight hours and time change items, and therefore this current maintenance plan has an effect on availability, maintainability and the Total Life Cycle Costs of the Apache. To reduce these Life Cycle Costs and to improve the availability, the Original Equipment Manufacturer (OEM) and the US Army (main user) continuously improve the Apache maintenance plan. At the beginning of the introduction of the Apache, the main focus of these improvements was the Mean Time Between Failure (MTBF) of components. Current innovations and refinements of the maintenance programs have helped and will help the RNLAF to decrease the Life Cycle Costs even more.

A later study based on the diagnosis and prognosis of mechanical systems was performed at the University of South Carolina’s Department of Mechanical Engineering and was called on-board Vibration Management Enhancement Program (VMEP). The primary functionality of VMEP consists of Rotor Track and Balance (RT&B) and Vibration Monitoring. This system consists of an on-board unit, a personal computer-based ground station and web-based data storage and analysis tools. The VMEP program objective is to develop a low cost, highly effective diagnostic tool, that is easily configurable to any future requirements, for rotor smoothing and vibration monitoring.

Considering the way the Apache usage affects the maintenance intensity as based on the maintenance plan, in order to achieve maximum maintenance effectiveness, the RNLAF would like to have possibilities for optimization of the Apache AH-64D Maintenance Plan. Together with the introduction of CBM, the intensity of the maintenance in the usage will also have an impact on the maintenance organization. CBM must lead to Maintenance effectiveness and this Maintenance effectiveness is the Availability divided by the Maintenance Cost. Because the program is delayed within the RNLAF a case study cannot be performed and therefore only a framework for a case study could be provided.

The main conclusions, findings and recommendations, of this dissertation are:

  • VMEP/MSPU has been developed with a background of using vibrations as indicators of aircraft health and fault diagnosis, and to capture detailed usage data for comparison with maintenance costs and availability.
  • Nowhere in literature, reviewed on HUMS, MSPU or CBM, was the impact of these systems on the maintenance organization addressed. The only impact mentioned was the morale and performance of the people, to convince flight and maintenance crew to believe in a predictive system.
  • The changes in usage will have impact on structural integrity and is expected not to be major on others like drive train system.
  • Based on what-if analysis and on the demand for corrective maintenance a FMECA of the drive train system is performed, and it is noted that the failure behavior was covered by different kind of inspections or indications.
  • Because of the introduction of MSPU as part of CBM the way of thinking and working, of the current organization, will change.
  • From the pre fielding survey it can noted that the majority of the staff members is familiar with the definition of CBM and VMEP/MSPU, but only about 40% of the staff members think that there will be a change in thinking; from reactive to proactive.
  • Because of the expected morale behavior of the maintainers, pilots, etc. It is very important that results of the introduction of MSPU be briefed frequently. Also other developments regarding CBM needs to be communicated to the involved.
  • Because of the fact MSPU is just introduced within the Apache Maintenance organization it would be recommended to evaluate the system by performing a case study.

De Thesis kunt u hier bekijken.(EN)

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