Why don't seats on airliners have shoulder straps, like the seats in (European) coaches often do? Wouldn't a shoulder-strap be more effective than adopting the brace position, in the event of a crash-landing?
There's no definite answer in the other question. Speculation that the brace position may be safer than a restrained torso but unrestrained head. Speculation that seats may not be strong enough to usefully hold a shoulder strap.
I'd like to know whether the lap-strap is a "legacy" pre-dating automotive shoulder-strap inertia-lock mechanisms (retained for economic reasons?), or whether lap-straps are actually known to be a safer solution in an aircraft environment (without air-bags, with a seat in front).