What you need to be concerned about, in ANY tip tanked Cessna, is the fact that right behind that pretty looking firewall, lies the crossfeed line. Now, all you knowledgeable wizzs' now that in the tip tank Cessna's there is NO way to shut off the crossfeeds. And also known is the crossfeeds go from one tank, clear across to the other sides fuel valve, located outside of the engine nacelle. So, if the exhaust elbow burns through (hidden behind a nice shield that is hard to inspect) you get about 1500 to 1600 degree exhaust burning a nice hole though that flimsy little aluminum firewall. Next stop,,, crossfeed line!
And, no way to shut it off. 50 gallons on fire inside your wing. Might be 100 gallons if it clips both lines. Did I mention that just behind the crossfied line was the spar?? OOOPS
Wings were lost. No joke. But just about every technician out there really does want us to live, so all the wise ones check that hidden exhaust bend like death warmed over. Just might be sad if the good guys who were privy to the mayhem retire, and the new generation don't know/remember what it was all about.
Hung