Originally Posted by
researcher1005
One thing I don't understand is many of 767/A310/A340/ built in 80s and even the oldest 777 have been retired and scrapped. Why would anyone retire a plane with plenty of cycles left?
Aircraft age is only one of many relevant factors.
The 340s turned out to be total fuel hogs compared to the available alternatives; many airlines that could afford to drop them, did, for a short-term loss but a long-term savings.
Age and cycles don't necessarily correspond either. For example, Dragonair (Cathay's regional arm) runs their A330 fleet on exclusively short routes - I think the longest is about 5 hours - so each airframe might rack up 3-5 cycles every day.
Meanwhile, Lufthansa, KLM and China Southern all use their A330s mainly on 8-12 hour routes - so each airframe will do 2 legs a day, max. Since as you've noted, cycles are one of the key factors in how long an airframe stays in service, Dragonair's 330s will be ready for retirement long before KLM's.
Last, keep in mind that the President of the United States flies around in a plane that's older than all of Air Canada's 767s.
Good mechanics make all the difference.