When I bought my Debonair from its previous owners, it had the original factory lap belts installed. As someone who had been flying airplanes equipped with three-point harnesses, it felt very exposed to be zooming around in something almost three times as fast as the car I drove to the airport but without even a shoulder strap to restrain me in the event “something” happened. One of the first upgrades I made to the plane was to add a set of four-point belts and harnesses to the front seats, and I’m happy to report I’ve never had to perform a real-world test of their effectiveness.
The Aeronca Champ I bought with a partner a couple of years back came with some kind of Rube Goldberg arrangement of belts purporting to restrain the occupant, but I’ve never been confident in them, and they actually make me reluctant to fly the airplane. Soon, they will be replaced with a system offering more comfort and at least as much restraint. If you’re still flying around with lap belts only, we strongly urge you to rethink your strategy and add some better restraints. Depending on the aircraft and your mouting options, it can as easy as getting your mechanic to install a few bolts and making a logbook entry.