Item — HN Reader

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-s...

2018, A320s grounded due to P&W failures: 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-fai...

1 comments

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.

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.

I've run the numbers here

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.

Oh right k for a week is not 2 but 2/52!