Your comment does not deserve to be downvoted, there is absolutely nothing wrong with it.
It's _exactly_ the kind of comment that deserves to be downvoted here.
It's curiosity, it's learning, it's looking for an explanation.
That's exactly the kind of comment that deserves to be here.
>[...] who doesn't have any relevant expertise,
Is that a requirement to comment on this thread?
Do you fulfill that requirement you brought in?
If I'm wrong, then apologies to the OP.
Yes, I've been on this website quite a long time, unfortunately.
Is that the topic of this thread?
So I was wondering what if current plane designs had 4 smaller but equally as efficient engines instead of 2. The vast majority of airplane accidents happen at takeoff or landings, if some of those can be avoided by having 4 engines for commercial aircraft, its a worthwhile idea to explore.
Also I would venture that 99% of comments on public forums like this are from people without expertise. My expertise in this space is a curiosity about planes for a few decades, taking some actual flying lessons, and being generally interested in aviation to go to airshows, watch youtube content from pilots, etc. I probably have about the same aviation knowledge as an average HN person.
Unironically, you're probably way more qualified than most of the people here throwing rubbish at you.
A classic on places like this.
Impossible to answer until we know the cause. If it was independent powerplant failures, then yes. If it was e.g. fuel contamination, pilots improperly shutting down the engine, some other crap failing, then no.
Speaking as someone with aerospace engineering and GA pilot experience.
It's pretty clear what the guy is inquiring about.
Speaking as someone without aerospace engineering or GA pilot experience. My only relevant experience here is being able to read.
Double bird strikes are “independent powerplant failures.”
"4 smaller but equally efficient engines" feels like a unicorn though (we'll probably get to the point in future where four large engines are superior in efficiency to two of today's engines, but two large engines to that latest design will still be more efficient than four smaller ones...)
With turbines, yes, for fundamental reasons. With electric motors, on the other hand, perhaps not, though not particularly relevant to a long-haul route like AMD-LON.
(I get to write about arrayed space thrusters in the day job too, but again, fundamentally different physics and goals...)
Apologies!
Smaller turbofan engines are less efficient than larger ones. This is because they have a lower bypass ratio - thrust generated by turning the big fan over the thrust generated by combustion.
So expect even bigger engines.
Larger jet engines are more fuel efficient than smaller ones, because larger diameters allow for more bypass air and therefore more fuel efficiency [1]. It is a function of size and a lot of the engineering goes into materials and designs to be able to increase size and maintain strength. So you simply can't make 4 engines that are as efficient as 2 large ones, and that is compounded by the significant additional weight (and drag) of the duplicated engine parts and mounting structures.
>if some of those can be avoided by having 4 engines for commercial aircraft, its a worthwhile idea to explore
Everything comes with tradeoffs. Adding more engines mean more complexity, more maintenance, more chance of single engine failures, etc. You don't want to introduce more failure modes than what you are trying to fix. The move to two engines for large aircraft and the evolution of ETOPS (Extended Twin-engine Operational Performance Standards) involved a lot of people considering a lot of scenarios. I can guarantee the "why not 4 engines" question has been studied extensively.
[1] https://simpleflying.com/why-do-jet-engines-keep-getting-lar...
We won't know until we have all the details and the exact cause of the shutdown.