Looking at the 2014 Allianz Global Aviation Safety Study for airliners:

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The last generation of aircraft (1974 and forward, including A320 and B737) have a very low rate of accidents: less than 2 accidents per million of departures. This rate is better than all previous generations.

However this rate is lower only one to 2 years after the model has been on the market. Prior to this milestone, the rate is higher than previous generations, except the very first one.

  • Why is the first year rate of accidents so relatively high? It seems we have almost the same number of accidents before two years, than during the rest of the aircraft life.

  • Is there an obvious reason for having aircraft of the last generation apparently less safe at their life beginning than the two previous generations?

  • 2
    $\begingroup$ For all generations, this looks rather like a bathtub curve. But the numbers here are small, so I'm not sure how to draw good conclusions from them. $\endgroup$
    – Pondlife
    Feb 4, 2018 at 4:45

1 Answer 1


Just a thought - when a new aircraft is introduced, if there is an accident/incident early on there are very few aircraft of that model flying and the million hour mark is hard to reach.

This may skew the accident rate wildly. Earlier generations were simpler and were turned out of the factory at a higher rate than newer, more complex aircraft.

  • 1
    $\begingroup$ The amplification effect plays a role in both cases: If accidents happen late in the period required to have 1M flights, the ratio is much lower during this period. So your answer is valid if the accidents happen early. So my first question: Are aircraft less safe at the beginning? On the other hand can 12 to 24 months be the time for having enough aircraft for 1M flights per year (2,700 flights per day) to explain much lower and stable rates? $\endgroup$
    – mins
    Feb 4, 2018 at 13:22
  • 1
    $\begingroup$ As time goes by, more experience and knowledge accumulates. This should increase the safety with each generation. The increasing complexity on the other hand, leaves more chance for so-called "infant failures" to creep into the operation. As I said, just a thought. $\endgroup$
    – Mike Brass
    Feb 5, 2018 at 0:31

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