A Framework for Objective Cosmetic Acceptance of Decoratively Laminated Aircraft Interior Panels: Defect Taxonomy, Severity Grading, and a Protocol for Measuring Inter-Inspector Variance

Decoratively laminated honeycomb and composite panels used in commercial aircraft cabins are released to the customer on the basis of a cosmetic acceptance inspection performed by the unaided eye. That inspection is commonly the one measurement in the quality system whose reproducibility has not been quantified and whose acceptance limits are not written in physical units. The consequence is a conformity decision that cannot be reproduced between inspectors, cannot be defended in a customer dispute, and cannot be used as a baseline for process improvement. This paper proposes a framework intended to make that decision measurable. It contains four parts. First, a set of three defined reference observation conditions, diffuse, grazing and specular, specifying illuminance, correlated color temperature, illumination geometry, observation distance, observation angle and dwell time, so that an inspection result is attached to the conditions under which it was obtained. Second, a taxonomy of nine cosmetic defect classes for decoratively laminated interior surfaces, each defined by its physical mechanism rather than by shop vocabulary, with a stable alphanumeric code. Third, a five-level severity grading scale, G0 through G4, in which every boundary between graded levels is expressed in a measurable physical quantity rather than as an adjective. Fourth, a protocol for measuring inter-inspector variance on a plant's own parts, which separates the search subtask from the disposition subtask, measures each with its own statistic, and states how the results are to be interpreted and reported. The framework is descriptive of method, not prescriptive of limits. It specifies how a cosmetic acceptance criterion should be written, measured and verified. It does not state what any particular manufacturer, customer or program should accept, and it reproduces no proprietary specification. The grading tables are templates with the physical dimension fixed and the acceptance threshold left to the contracting parties. The framework addresses appearance only. It has no regulatory status and no bearing on airworthiness, on flammability, smoke and heat release, or on structural integrity.