Like 'airframe', 'air vehicle' and 'aircraft', 'air system' is appropriate when used in the correct context. But to replace all instances of 'aircraft' with 'air system' would be to show a worrying lack of understanding, akin to inappropriate use of 'fault' and 'defect'. What aircrew really need to know is that the people responsible for each are doing their jobs correctly. Initially, and in practice, getting it wrong means there ain't enough funding. Look at it positively. This could be an attempt to return to making correct materiel and financial provision, which is a Service HQ function. If only they knew it.