Boeing declined to comment on details that are under investigation by the National Transportation Safety Board. The report follows an earlier one from Reuters that said Boeing has a key role in installing and checking the part, made by fuselage supplier Spirit AeroSystems, which was spun off from Boeing in 2005. Sources told Reuters that Boeing typically removes the panel and replaces it, while a source familiar with Boeing's standard industrial processes insisted Boeing only adjusts or removes the panel if there are signs it was installed incorrectly.