Ascend research suggests that while there is evidence of a current downtrend in the useful economic life of aircraft, it is too early to conclude if this is a cyclical or structural trend.
"From today's perspective, there is little doubt that commercial jet aircraft are presently retiring earlier, and also in larger volumes, compared with the period before 2008," writes Ascend's senior analyst Rob Morris in the firm's current Viewpoint newsletter.
According to data extracted from the Ascend Online Fleets database, in 2008 the average age of the 521 commercial jet aircraft permanently retired from service was 31.5 years, or 28 years, if adjusted for time spent in storage prior to final retirement. Whereas, in 2012, those average ages had fallen to 27.1 years and 24.8 years, respectively for the 591 aircraft currently recorded as retired, according to Morris.
About 49% of the aircraft retired in 2012 were less than 25 years old and 9% - 54 aircraft - were less than 15 years old at retirement.
In addition, since 2010, 6.1% of all aircraft retired have been less than 15 years old.
According to Morris, high fuel prices, probably here to stay, support the argument of a structural trend.
"High fuel prices are challenging the operating economics of previous and some current generation aircraft types," he says.
Furthermore, increasing levels of aircraft age restrictions, which prevent the import of aircraft to some countries beyond a certain age, as well as increased utilisation, which has driven aircraft and engines to "significant and costly maintenance events" earlier than would have previously occurred, are also suggestive of structural change, notes Morris.
On the flip side, continued high production rates reinforce the argument of a cyclical trend, he says.
"This has inflated the availability of new current generation aircraft, driving the premature retirement of aircraft that may otherwise have remained in service in the absence of new aircraft deliveries," according to Morris.
Since 2008, Ascend estimates that 55% of all passenger aircraft deliveries have been for replacement rather than growth.
Further fuelling the cyclicality argument are low interest rates, "which have driven cheap and available financing".
"This, together with the continued growth of operating leasing, have facilitated the delivery of new aircraft, often to operators that would not have been able to access new aircraft for fleet growth or replacement in previous cycles," says Morris.
In addition, limited financing for older aircraft, weak freight markets and an increasing level of airline failures further back the argument of cyclical change, he says.
"This whole debate has a long way to go before a conclusion can be reached and Ascend will continue to monitor and participate in this discussion as our thoughts develop," Morris concludes.