System Maintenance

Introduction

For a system to be sustained throughout its system life cycle, the Maintenance Process has to be executed concurrently with the Operations Process (ISO 15288 Clause 6.4.9). The requirements for maintenance have to be defined upfront during the Stakeholder’s Requirement Definition Process (Clause 6.4.1). Considerations include:

• Maximizing system availability to meet the operational requirements. This has to take into account the designed-in reliability and maintainability of the system.

• Preserving system operating potential through proper planning of system scheduled maintenance. This requires a reliability-centered maintenance strategy that incorporates preventive maintenance in order to preempt failures thereby extending the mean time between corrective maintenance and this enhances the availability of the system.

• Outsourcing non-critical maintenance activities so as to optimize scarce technical manpower resources.

• Harness IT technology for maintenance management. This involves rigorous and systematic capturing and tracking of operating and maintenance activity to facilitate analysis and planning.

Maintenance management concerns the development and review of maintenance plans, securing and coordinating resources such as budget, service parts provisioning, etc., and management of supporting tasks such as contract administration, engineering support and quality assurance.

Process Approaches

The purpose of the Maintenance Process is to sustain the capability of the system to provide a service. This process monitors the system’s capability to deliver services, records problems for analysis, takes corrective, adaptive, perfective and preventive actions and confirms restored capability.

As a result of the successful implementation of the Maintenance Process:

• A maintenance strategy is developed.
• Maintenance constraints are provided as inputs to requirements.
• Replacement system elements are made available.
• Services meeting stakeholder requirements are sustained.
• The need for corrective design changes is reported.
• Failure and lifetime data is recorded.

The project should implement the following activities and tasks in accordance with applicable organization policies and procedures with respect to the Maintenance Process:

• System preparation for operations, including system performance verification before operation.
• Scheduled servicing such as daily inspection/checks, servicing, cleaning.
• Unscheduled servicing (carrying out fault detection and isolation to the faulty replaceable unit and replacement of the failed unit).
• Re-configuration of the system for different roles or functions.
• Scheduled servicing - higher level scheduled servicing but below Depot level.
• Unscheduled servicing (carrying out more complicated fault isolation to the faulty replaceable unit and replacement of the failed unit).
• Minor modifications.
• Minor damage repairs.
• Major scheduled servicing, e.g. overhaul, corrosion treatment
• Major repairs (beyond normal removal and replacement tasks).
• Major modifications.

The maintenance plan specifies the scheduled servicing tasks and intervals (Preventive Maintenance) and the unscheduled servicing tasks (Adaptive or Corrective Maintenance). All the tasks in the maintenance plan are allocated to the various maintenance agencies. A Maintenance Allocation Chart is developed to tag the maintenance tasks to the appropriate maintenance agencies. These include in-service or in-house work centers, approved contractors, affiliated maintenance or repair facilities, OEMs, etc. The maintenance plan also establishes the requirements for the support resources.

Related activities such as resource planning, budgeting, performance monitoring, upgrade, longer term supportability and sustenance also need to be managed. These activities are being planned, managed and executed over a longer time horizon and they concern the well being of the system over the entire life cycle.

Proper maintenance of the system relies very much on the availability of support resources such as Support and Test Equipment (STE), Technical Data, and Facilities. These have to be factored in during the Acquisition Agreement Process.

Methods & Tools

Training and Certification

Adequate training must be provided for the technical personnel maintaining the system. While initial training may have been provided during the Transition Process, additional personnel may need to be trained to cope with the increased number of systems being fielded as well as to cater to staff turnover. It is important to define the certification standards and contract for the training materials as part of the Supply Agreement.

Practical Considerations

The organization responsible for maintaining the system should have clear thresholds established to determine whether a change requested by end users, changes to correct latent defects, or changes required to fulfill the evolving mission are within the scope of a maintenance change or require a more formal project to step through the entire systems engineering life-cycle. Evaluation criteria to make such a decision could include cost, schedule, risk, or criticality characteristics.

References

Primary References

Blanchard, B.S., Fabrycky, W.J. Systems Engineering and Analysis, 3rd Edition, Prentice Hall, 1997

Systems Engineering Book of Knowledge, Ver 2.0, Institution of Engineers, Singapore, Singapore.

INCOSE Systems Engineering Handbook, Section 6.7 Acquisition Process, INCOSE-TP-2003-002-03.1, Version 3.1, August 2007.

ISO/IEC 15288, IEEE Std 15288-2008 (2008). Systems and software engineering - System life cycle processes (2nd edition). Software & Systems Engineering Standards Committee, IEEE Computer Society.

Defense Acquisition University, Defense Acquisition Guidebook, https://acc.dau.mil/CommunityBrowser.aspx?id=289207, 17 December 2009

Additional References

All additional references should be listed in alphabetical order.

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