sia777SINGAPORE—The Singapore Airs (SIA) Boeing 777-300ER that suffered severe turbulence on May 21 experienced a gravitational force shift from +1.35G to -1.5G overSINGAPORE—The Singapore Airs (SIA) Boeing 777-300ER that suffered severe turbulence on May 21 experienced a gravitational force shift from +1.35G to -1.5G over