Exhaust springs falling off into the prop is popularly supposed only to affect 447 'pusher' planes, but the springs should be stainless steel lock wire secured individually through the centre and then to each one's lug so at least they cannot fall away.
Silicone "RTV" sealant squeezed out of its tube to form a 'slug' over the length of each spring will prevent it vibrating/chattering which action otherwise would wear the spring eye through or the tab on the exhaust itself can wear badly.
