Is it all coincidence or is there some environmental factor? These engines aren't exactly new -- they were first introduced in 1984. I'd expect design issues would have manifested already.
The significant environmental factor is that many planes have been sitting idle for months. This is exceptionally unusual in the life of most airframes. Idle time is an opportunity for parts or fluids to settle in a way they might not otherwise.
For example an extremely slow fluid leak could be “reset” every time the engine is operated. Allow time for fluid to accumulate and suddenly there’s enough fluid where it shouldn’t be, perhaps causing just enough mechanical stress to exacerbate an previously unknown wear point or design flaw present in a tiny minority of copies.
(Of course this hypothetical flaw couldn’t cause catastrophe on first flight, as that is generally an empty plane travelling from long term storage back to the airline’s hub airport. The flaw would have to subtly weaken a part which then fails after multiple rounds of uneventful flights.)
I recall reading an article in Aviation Week maybe 30 years ago about turbine blades failing for an unknown reason, and it turned out it had to do with contaminates in the water they were using during engine builds or some such.
This was an elderly freighter, for which months of idle time in between owners isn't exactly uncommon in normal times. And in the case of this aircraft, it was actually acquired last year because the charter operator saw an increase in demand.
"Another [Boeing's (if you insist)] Pratt and Whitney Engine ..." would be a better title, Boeing has little to nothing to do with the engine, and Pratt and Whitney engines are found on Airbus aircraft too.
Jet engine metallurgy takes a lot of work to get right. It’s highly technical and the mfgs hold on to their know-how as much as they can.
So aircraft, yes, a number of countries are capable of building their own and do. Jet engines are more specialized and we’ve ended up with three major specialized engine mgfs: Rolls, P&W and GE. Anyone know of other contenders?
I am wondering how much is this a maintenance issue during pandemics - planes are likely flying less often, exposing some issues from standing still; repair crews might not be available all the time or suddenly overloaded and because of these factors the rate of incidents rises?
Planes are grounded if maintenance can't be done. The quality of maintenance can vary from the norm as maintenance companies are starved for work and lay people off.
Normal maintenance doesn't involve disassembling engines and messing with turbine blades.
Normally it's birds causing these blade destructions. All those incidents point to birds. The question should be, why suddenly so many birds near airports?
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.
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.
24 comments
[ 2.1 ms ] story [ 54.8 ms ] threadFor example an extremely slow fluid leak could be “reset” every time the engine is operated. Allow time for fluid to accumulate and suddenly there’s enough fluid where it shouldn’t be, perhaps causing just enough mechanical stress to exacerbate an previously unknown wear point or design flaw present in a tiny minority of copies.
(Of course this hypothetical flaw couldn’t cause catastrophe on first flight, as that is generally an empty plane travelling from long term storage back to the airline’s hub airport. The flaw would have to subtly weaken a part which then fails after multiple rounds of uneventful flights.)
> Boeing 747 loses parts after take-off from Maastricht – 2 injuries (aviation24.be)
> 104 points by UncleOxidant 2 days ago | 40 comments
https://news.ycombinator.com/item?id=26209611
I can't wait for the Chinese to build aircrafts too so we can get a bit of a kick in the ass and re-focus.
So aircraft, yes, a number of countries are capable of building their own and do. Jet engines are more specialized and we’ve ended up with three major specialized engine mgfs: Rolls, P&W and GE. Anyone know of other contenders?
https://en.wikipedia.org/wiki/Williams_International
Upon checking it turns out Safran engines are a franco-american partnership anyway with GE, grrr :D
Normal maintenance doesn't involve disassembling engines and messing with turbine blades.
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...
Poisson distribution could tell how improbable it is but I'm lazy.
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.
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.