Originally Posted by
EWR764
As it relates to N641UA, yes it is an "old" airframe in person-years, but at present utilization levels it has no fewer than 6-7 years of "life" left before reaching its certificated design limit... which is well short of its actual (tested) structural life limit. The question is at which point the cost to maintain becomes so prohibitive that it negates the cash flow the asset can generate in service, especially considering how valuable the 767's core mission in the UAL network has become in the last few years. I think the proof is in the pudding.
As you said, this type of damage has occurred on multiple 767-300s at multiple operators. As far as I know, they have all been repaired and returned to service.
It might be worthwhile to consider what happens to 767s when they are retired by passenger airlines. They are converted into freighters and continue to fly for several decades longer delivering your Amazon and DHL, and other packages and freight. (I'm not sure if UPS or FDX have used any converted passenger 767s or if all of their's were purchased new)
These airplanes have a lot of life in them when passenger airlines typically retire them. That gives passenger airlines a lot of flexibility in the refurbish vs. replace decision. At the moment, there is no direct replacement for the missions that these airplanes fly so refurbish is going to win out for longer than it otherwise might.