the legacy approach of three distinct tests, that is, shaking a load first in its x axis, then its y axis, and finally in its z axis. A matrix of the tests and methods of MIL-STD-810 through Revision G is available on the web and quite useful in comparing the changes among the various revisions . The following table traces the specification's evolution in terms of environmental tailoring to meet a specific user's needs. MIL-STD-810, Part one - General program guidelines Part One of MIL-STD-810 describes management, engineering, and technical roles in the environmental design and test tailoring process. It focuses on the process of tailoring design and test criteria to the specific environmental conditions an equipment item is likely to encounter during its service life. New appendices support the succinctly presented text of Part One. It describes the tailoring process (i.e., systematically considering detrimental effects that various environmental factors may have on a specific equipment throughout its service life) and applies this process throughout the equipment's life cycle to meet user and interoperability needs. MIL-STD-810, Part two - Laboratory test methods Part Two of MIL-STD-810 contains the environmental laboratory test methods to be applied using the test tailoring guidelines described in Part One of the document. With the exception of Test Method 528, these methods are not mandatory, but rather the appropriate method is selected and tailored to generate the most relevant test data possible. Each test method in Part Two contains some environmental data and references, and it identifies particular tailoring opportunities. Each test method supports the test engineer by describing preferred laboratory test facilities and methodologies. These environmental management and engineering processes can be of enormous value to generate confidence in the environmental worthiness and overall durability of equipment and materiel. Still, the user must recognize that there are limitations inherent in laboratory testing that make it imperative to use engineering judgment when extrapolating from laboratory results to results that may be obtained under actual service conditions. In many cases, real-world environmental stresses (singularly or in combination) cannot be duplicated practically or reliably in test laboratories. Therefore, users should not assume that a system or component that passes laboratory tests of this standard also would pass field/fleet verification trials. Specific examples of Test Methods called out in MIL-STD-810 are listed below: Test Method 500.6 Low Pressure (Altitude) Test Method 501.6 High Temperature Test Method 502.6 Low Temperature