Qualification of low-density materials for aircraft corrosion protection and integral fuel tank sealing

摘要

Low-density polysulfide-based sealants are at the leading edge of engineering technology for sealing processes applicable to military and commercial aircraft. This paper focuses on a major aircraft manufacturer's quality assurance (QA) system dedicated to testing and evaluating sealants for placement on applicable Qualified Products Lists (QPLs). This QA system enabled this aircraft manufacturer to qualify two Class C designations - Classes C-2 and C-48 - of low-density sealants. The generic procedure for qualification of low-density sealants, especially Class C materials, is explained from the aircraft manufacturer's point of view. The Engineering decision-making process for selecting and documenting property test requirements for qualification of aircraft sealants is discussed. Despite the time-intensive nature of the generic sealant qualification process, the author concludes that sealant qualification is a worthwhile and necessary effort, which demands comprehensive testing and frequent technical coordination within airframe manufacturer's Engineering and Material organizations and with suppliers of aircraft sealing products.