When is a statistical sampling plan typically applied in aerospace manufacturing?

When is a statistical sampling plan typically applied in aerospace manufacturing?

• A. A plan specifying inspection for all items always.
• B. A plan specifying sample size and acceptance criteria; used in incoming, in-process, or final inspections based on risk.
• C. A schedule for calibration of equipment.
• D. A method for tracing materials in the supply chain.

Answer: (B)

A statistical sampling plan defines how many items to inspect and what results will trigger acceptance or rejection, with decisions based on risk. In aerospace manufacturing, this approach is used at multiple points—incoming supplier lots, in-process production, or final acceptance—so quality decisions can be made without inspecting every item. The plan specifies the sample size for a given lot, the lot size, and the acceptance criteria (how many defects are allowable in the sample). If the observed defects stay within the acceptance number, the lot passes; if they exceed it, the lot is rejected or subjected to further action. This balances the need for safety and reliability with the cost and time of inspection, adapting to the risk associated with different parts and processes. The other options describe exhaustive inspection, calibration scheduling, or traceability methods, which are separate activities and do not define a statistical sampling approach.

A statistical sampling plan defines how many items to inspect and what results will trigger acceptance or rejection, with decisions based on risk. In aerospace manufacturing, this approach is used at multiple points—incoming supplier lots, in-process production, or final acceptance—so quality decisions can be made without inspecting every item. The plan specifies the sample size for a given lot, the lot size, and the acceptance criteria (how many defects are allowable in the sample). If the observed defects stay within the acceptance number, the lot passes; if they exceed it, the lot is rejected or subjected to further action. This balances the need for safety and reliability with the cost and time of inspection, adapting to the risk associated with different parts and processes. The other options describe exhaustive inspection, calibration scheduling, or traceability methods, which are separate activities and do not define a statistical sampling approach.