FAR 25.303 requires a substantial safety margin for structural loads. § 25.303 Factor of safety. Unless otherwise specified, a factor of safety of 1.5 must be

FAR 25.303 requires a substantial safety margin for structural loads. § 25.303 Factor of safety. Unless otherwise specified, a factor of safety of 1.5 must be applied to the prescribed limit load which are considered external loads on the structure. When a loading condition is prescribed in terms of ultimate loads, a factor of safety need not be applied unless otherwise specified. https://www.law.cornell.edu/cfr/text/14/25.303 https://www.law.cornell.edu/cfr/text/14/25.303 Airplanes in the United States are extraordinarily well maintained. Certified airplanes (which include all airliners) must be inspected annually to maintain airworthiness. Yes, you do hear stories of inspections sometimes being pencil-whipped, but these are by far the exceptional cases. The inspection has to be at least supervised (if not performed) and signed off by a certified Airframe & Powerplant (A&P) mechanic with an Inspection Authorization (IA). The A&P certificate requires training, passing a written knowledge test, passing an oral grilling, and passing a practical test. The IA requires additional training and testing. Someone with that much invested is not going to screw around. The annual inspection itself is detailed and thorough, not a quick eyeball. Any discrepancies or issues (squawks) the A&P discovers are potential followon work. Serious squawks must be addressed before the airplane is airworthy, i.e., legal to fly. Further, any airplane flown commercially (be it for flight instruction, aerial survey, or transportation) must be inspected to the standard above after every hundred flight hours. Commercial operators have special certificates to allow them to conduct business that they likewise will not jeopardize by foolishly cutting corners. Commercial pilots have hundreds or thousands of hours and tens of thousands of dollars invested, so they also have a huge personal stake in playing by the rules. Turbulence is no fun. Catastrophic failure would be even less fun. Safety rules, procedures, systems, and backups are in place that keep safety at the forefront. The airplane can take it. People with significant stake personally and financially have checked, rechecked, and signed off saying that it is safe.