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Comment by ExoticPearTree | Hacker News Reader

I'm curious how much it was saved in money and/or weight that it made sense to someone to make the cowling out of "plastic" :)

Sometimes it feels like the decision process at Boeing is:

- How big of a problem $this can be?

- Disaster like

- Go for it.

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Very likely no money was saved by Boeing, composites are almost always more expensive.

Maybe someone with aviation industry knowledge can reply, but my guess is adding a trivial timed shutoff would have triggered an elaborate FAA approval and certification process. That’s probably where the savings were.

The “savings” is entirely due to weight. More weight requires more fuel. The single biggest cost by a large margin in the life of a commercial airline jet is fuel. Increase fuel efficiency by even 1% and you save the airline industry billions.

Source to backup the claim of the scale of worldwide airline fuel usage: https://www.statista.com/statistics/655057/fuel-consumption-...

Source to give you an idea of how much US airlines pay for fuel: https://www.bts.gov/newsroom/us-airlines-january-2023-fuel-c...

I was thinking about weight, but the cowlings are pretty small compared to other parts of the plane where composite materials are used. So i'm not sure a single digit saving in pounds of fuel per hour or flight was a good tradeoff considering the risks associated with the alternative they went with.

But, like someone else said this here, I would love someone with knowledge about this to chime in.

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