"(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
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