When is an aircraft too old to fly?

Too old to fly is usually a topic associated with the age of the pilot but when is an aircraft too old to fly? A recent article by Richard Collins for Air Facts Journal noted that 1979 was the last year that a significant number of aircraft were built (along with the few year period before that) while the last time production figures were this low was in 1952. This means that much of the aircraft fleet is around 33 years old or older. Hence and for younger pilots, the aircraft they fly might actually be older than they are.

Moreover, Richard noted that a friend of his has put in at least $30,000 into an old twin for routine maintenance over 12 months – and the aircraft is probably worth only about five times as much that maintenance bill. And while Richard pointed out that its easy to think that some aircraft will never wear out (think of the B-52s or DC-3s that are still flying), that’s only true if you have significant amounts of money to spend on maintenance (the USAF etc.) and perhaps if the aircraft’s maker is still in business. After all, getting parts for an old aircraft can be a challenge – especially if the aircraft maker has long sense merged or been put out of existence. 

Finally and aside from the maintenance cost issue, the next concern with older aircraft would be the risks associated with flying one. Richard wrote that he has researched the subject of risk with older aircraft and has concluded that there is no way to know for sure just what the relationship is between the number of hours flown and accident rates.

Of course, mechanical related incidents with older aircraft are always higher than with newer aircraft with poor or inadequate maintenance usually be blamed for any incident. 

That brings us to the following question: How comfortable are you flying older aircraft (even if you know its probably been reasonably well maintained) verses newer aircraft? In other words and aside from any cost considerations, do you feel more comfortable flying a newer aircraft verses an older aircraft and just when is an aircraft too old to fly?