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We're still riding the 737 MAX scare wave (from 2019) in the news, so while these incidents are infrequent, they are not as new as this reporting might suggest.

We're still riding the 737 MAX scare wave (from 2019) in the news, so while these incidents are infrequent, they are not as new as this reporting might suggest. 2018, passenger killed when fan blade penetrated cabin. Also mentions a 2016 incident: https://www.seattletimes.com/business/boeing-aerospace/one-southwest-passenger-dead-others-injured-after-boeing-737-engine-blowout/ https://www.seattletimes.com/business/boeing-aerospace/one-s... 2018, A320s grounded due to P&W failures: https://www.businesstoday.in/sectors/aviation/dgca-grounds-11-a320-neo-planes-pratt-and-whitney-engines-indigo-engine-failure/story/272444.html https://www.businesstoday.in/sectors/aviation/dgca-grounds-1... 2017, similar cowling stripped off in flight on A380: https://www.journalinquirer.com/business/pratt-ge-engine-failure-forces-emergency-landing/article_7f9fb4b0-a786-11e7-9693-9fd0838f36b8.html https://www.journalinquirer.com/business/pratt-ge-engine-fai...

jojobas 6y ago
Flight frequency is still less than half of normal. With reduced frequency you wouldn't expect a years worth of total engine failures in a week. Poisson distribution could tell how improbable it is but I'm lazy.
- raws 6y ago
  2¹⁰⁴*e-²2/(104!)=2.66523e−136 If annual occurence is 2 and it happens twice every week in a year. But it has not so far :) Weekly occurence of 0 has 13.5% chance of happening this being the case for 7 weeks before this last 8th 2021, 13.5*7/8= 11.8% so far. But I'm no statistician.
  - jojobas 6y ago
    I've run the numbers here https://stattrek.com/online-calculator/poisson.aspx https://stattrek.com/online-calculator/poisson.aspx At a weekly probability of 0.04 (2 failures/52 weeks) the probability of 2 failures within a week is 0.077%. The probability of 0 failures in a week is 96%. Accounting or halving of flight frequency it's 0.02% and 98% respectively.
    - raws 6y ago
      Oh right k for a week is not 2 but 2/52!

jojobas 6y ago

Flight frequency is still less than half of normal. With reduced frequency you wouldn't expect a years worth of total engine failures in a week. Poisson distribution could tell how improbable it is but I'm lazy.

raws 6y ago
2¹⁰⁴*e-²2/(104!)=2.66523e−136 If annual occurence is 2 and it happens twice every week in a year. But it has not so far :) Weekly occurence of 0 has 13.5% chance of happening this being the case for 7 weeks before this last 8th 2021, 13.5*7/8= 11.8% so far. But I'm no statistician.
- jojobas 6y ago
  I've run the numbers here https://stattrek.com/online-calculator/poisson.aspx https://stattrek.com/online-calculator/poisson.aspx At a weekly probability of 0.04 (2 failures/52 weeks) the probability of 2 failures within a week is 0.077%. The probability of 0 failures in a week is 96%. Accounting or halving of flight frequency it's 0.02% and 98% respectively.
  - raws 6y ago
    Oh right k for a week is not 2 but 2/52!