Re:Joby Aviation: Stress Engineer -- Occupant Seat (Score 1)

There are FAA regulations for passenger seating on airlines and can't be installed without proper certification. If they are not compliant, the plane will be grounded until airworthiness is provided. Airlines themselves are typically not responsible for the certification, it's the companies designing and manufacturing the seats that do the testing and certification. One of the seat tests is a 16g forward load carried out on a sled. 180lb*16g = 2880lbf per person with a large moment that has to be reacted at the seat rails. You start with the payload (180lb), then analyze the reacted load at each component all the way down to the floor grid. Each component has a margin of safety requirement. Everything that is installed onto a passenger airline has to be certified (stress, flammability, etc.) with a paper trail. Older retrofitted airplanes (new seats, infotainment, stowage bins, closets, lavatories, etc.) aren't cheap. Every time an airline wants to change seats/seating layout, it has to be re-certified for each configuration which is expensive. Also, I wouldn't worry about the seat failing and breaking since the likelihood of surviving a 16g crash is probably low. I'd worry about projectiles in the cabin from lower impact crashes being a bigger issue. Working in aerospace stress, you develop an aversion to flying cause you see all the things in the cabin that are likely to fail first and kill you.