“On many foreign carriers, parents can (loosely) secure their child with a belly loop belt that wraps around the baby’s torso and attaches to the adult’s seat belt. However, the FAA prohibits this accessory on U.S. carriers because of its potential dangers.”
Fwiw when I’ve used the baby-belts they felt very secure. Always wondered why US airlines didn’t use them.
There appear to be very good reasons.
From the Study on Child Restraint Systems: Final Report produced by TÜV Rheinland for the European Aviation Safety Agency in 2008 [0]:
–quote–
The loop belt is derived from the normal lap belt (width, material, buckle). The normal lap belt is designed to support the webbing on the iliac crest of the adult. In biomechanical terms, the adult is restrained by the lap belt over his or her iliac crest in an accident (cf. section 2.1.1). In infants, however, the iliac crest is not yet fully developed. The loop belt therefore rests by almost 100 percent within the infant’s abdominal region. The induction of forces into the abdominal region of the infant results in extremely serious internal injuries.
For this reason, the loop belt is no safety system for infants in turbulence, aborted take-off, hard landing, in emergency landing conditions and other accidents.
Furthermore, the infant is seated within the adult’s excursion path. Dummy tests in emergency landing dynamic conditions illustrate the situation of an infant fixed with a loop belt on the lap of an adult. They show the following pattern:
The inertia forces resulting from the mass of the infant and the effective accelerations affect the abdomen of the infant via the loop belt. Since the abdomen cannot induce exterior forces, the loop belt drives into the soft parts. The infant is additionally loaded by the pressure of the downward movement of the adult’s upper torso and his or her femurs hitting upwards. The loop belt drives through the infant’s abdomen and only stops at the vertebral spine. The adult hits onto the infant. The infant is pushed through the legs of the adult and hits onto the floor.
Infants fixed with a loop belt suffer extremely serious to fatal injuries due to their position within the adult’s excursion path and due to the restraint method.
–end quote–
[0] https://www.icao.int/safety/airnavigation/OPS/CabinSafety/Ca... (pp. 74-75)