[noughtme]

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.

[jsjohnst]

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...

[ExoticPearTree]

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.