ENGINEERING ADVANTAGE
MIL-HDBK-1916—the companion document to MIL-STD-1916, for guidance only—describes tools such as Process Capability and Statistical Process Control that can be used to meet MIL-STD-1916 requirements.
The AOZ sampling tables are the alternate methods of acceptance. MIL- STD-1916 has a unified approach to lot inspection by attributes, lot inspec- tion by variables, and continuous sampling by attributes. The verifica- tion levels (VLs) determine the level of effort in the sampling plan; the higher the verification level, the larger the sample size. All sampling plans use lot acceptance on zero nonconforming items in the sample and lot rejection on one nonconforming item.
While technical data packages note the VLs associated with the characteristics, that does not indicate a preference for acceptance by sampling, merely a minimum threshold that must be met if acceptance by sampling is desired. This misunderstanding has cre- ated confusion among government and contractor personnel.
2. MIL-STD-1916 is not applicable because specifications note 100 percent inspection for Critical Characteristics.
MIL-STD-1916, when specified in the contract, includes requirements that go beyond 100 percent inspec- tion. More specifically, Paragraph 4.4 calls for a VL-VII sample to be taken after 100 percent inspection to vali- date the effectiveness of the inspection equipment and the applicable process. Consequently, detection of any criti- cal nonconformance would result in actions as prescribed in Paragraph 4.5 of MIL-STD-1916.
3. MIL-STD-1916’s sampling tables specify an AQL and therefore inher- ently allow acceptance of some nonconforming product.
Sampling plans do not use AQLs, and the government’s expectation is total conformance to contract require- ments. In certain cases, misinformed positions have stated that due to the statistical probability of a defect occurring within the lot, the AOZ plan is equivalent to an AQL-based acceptance requirement. This is false.
MIL-STD-1916 HAS OFTEN BEEN MISUNDERSTOOD, RESULTING IN MISAPPLICATION OF REQUIREMENTS AND PREVENTING THE GOVERNMENT
AND/OR CONTRACTOR FROM REAPING ITS FULL BENEFITS.
90 Army AL&T Magazine
There is always a balance between producer and consumer risks; the AOZ plan stipulated in MIL-STD-1916 reinforces the cus- tomer’s expectation that if a defect is found in the sample, the manufacturer must screen the prod- uct (at 100 percent) to remove any nonconformances.
The incentive is to guide contractors toward acceptance based upon pro- cess control, thereby preventing defects from occurring, rather than sampling and not improving their processes. The contractor’s quality system, including manufacturing, inspection, material handling processes, and quality control measures, will be established and oper- ated to consistently produce product that meets all requirements in accordance with Federal Acquisition Regulation 52.246-11, Higher-Level Contract Quality Requirement, or similar local nonstan- dard clauses that typically specify an ISO 9001-based QMS. Absence of any inspection or process control requirement in the contract does not relieve the con- tractor of responsibility for ensuring that all product submitted to the government conforms to all contract requirements.
The sampling plans and procedures of MIL-STD-1916 are not intended for use with destructive tests or when product screening is not feasible or desirable. In such cases, the sampling plans for use will be specified in the contract or product specifications. Paragraph 1.5 of MIL- STD-1916 notes these limitations.
OPPORTUNITIES FOR EFFICIENCIES Notwithstanding the inefficient aspects of sampling, MIL-STD-1916 provides sets of sampling plans. However, as noted previously, these are alternate preferences. The primary focus of MIL-STD-1916
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