This Appendix is an essential part of MIL-HDBK-470A. The information contained herein is intended for reference only. Much of this appendix is based on the information that was contained in MIL-HDBK-471 (formerly MIL-STD-471A), Maintainability Verification/ Demonstration /Evaluation. Although the referenced document covered verification, demonstration and evaluation, the methods presented dealt primarily with maintainability demonstration. Part of the reason is that separate tests designed and planned specifically to verify or evaluate the maintainability characteristics of a design have not typically been part of a system development program. In the case of reliability, testing such as reliability growth testing is a separate process from reliability qualification testing or production reliability acceptance testing. No such techniques, in the form of handbooks or standards have been developed for similar (e.g., maintainability growth) testing associated with maintainability. Consequently, in this Appendix, specific techniques for maintainability demonstration testing will be presented, while other types of maintainability testing (i.e., verification and evaluation) will be addressed from a more qualitative aspect.
This Appendix is for guidance only and cannot be cited as a requirement. If
it is, the contractor does not have to comply.
B.1.1 - Purpose
The purpose of conducting maintainability tests is to verify, demonstrate
and evaluate both quantitative and qualitative maintainability
characteristics of a design. Quantitative parameters include metrics
discussed elsewhere in this handbook, such as MTTR, Mct, or
B.1.2 - Definitions
The following terms, used and discussed within this appendix are as
defined as follows:
B.1.2.1 - Maintenance Task
The maintenance effort necessary for retaining an item in, changing to,
or restoring it to a specified condition.
B.1.2.2 - Maintainability Model
A quantifiable representation of a test or process the purpose of which
is to analyze results to determine specific relationships of a set of
quantifiable maintainability parameters.
B.1.2.3 - Verification
The effort performed from system concept through the hardware development
phase to: determine the accuracy of and update the analytical (predicted)
data obtained from the maintainability engineering analysis, identify
maintainability design deficiencies, and gain progressive assurance that the
maintainability of the system or item can be achieved and demonstrated in
B.1.2.4 - Demonstration
The effort (often performed jointly by the system developer and system
procuring activity) to determine whether specified maintainability
B.1.2.5 - Evaluation
The procuring activity effort to determine, at all levels of maintenance,
the impact of the operational, maintenance and support environment on the
maintainability parameters of the system or item and to demonstrate depot
level maintenance tasks.
B.1.2.6 - Maintenance Concept
A description of the planned general scheme for maintenance and support
of an item in the operational environment.
B.1.2.7 - Maintenance Environment
climatic, geographical, physical and operational conditions (e.g., combat,
mobile, continental) under which an item will be maintained.