[oceanplexian]

A modern airliner is rated to something like 3-4G's including the safety factor, probably much more if it's not at max takeoff weight. I'm sure you could do a Mythbusters-style test but I'd assume most passengers would pass out from the negative and positive G forces long before the aircraft structurally failed.

[TylerE]

You'd lose that bet. The wings would fail long before people blacked out. They're only required to withstand 2.5g positive. Blacking out takes more like 6. We can see from various crashes that that sort of G load does in fact cause most wings to fail.

Aircraft have to be built light for the sake of efficiency (or even, just, being able to get off the ground.

There are certainly factors of safety... but not 3x+. Probably closer to 1.5.

[bozhark]

I would like proof of this absurdly low 2.5g wing rating.

[TylerE]

It's right in the FAA regs.

https://www.law.cornell.edu/cfr/text/14/25.337

"(b) The positive limit maneuvering load factor n for any speed up to Vn may not be less than 2.1 + 24,000/ (W + 10,000) except that n may not be less than 2.5 and need not be greater than 3.8—where W is the design maximum takeoff weight.

(c) The negative limit maneuvering load factor—

(1) May not be less than −1.0 at speeds up to VC; and "

The 2.5 number is important. That right there is the +2.5 to -1.0 requirments for transport (i.e. seating more than 19 passengers) category aircraft.

Here's a quote from Boeing: "Our airplanes are built to withstand 3.75 G load before there is any kind of damage — that's almost four times gravity,” said Doug Alder, a spokesman for Boeing. “Some of the worst turbulence gets in the range of 2 to 2.5 G's, well below the damage tolerance.”

3.75 is not nearly enough to cause a blackout. It's also exactly 1.5 (typical airplane factor of safety) times 2.5