SINGAPORE, May 29 (Reuters) - Preliminary findings from

an investigation into a Singapore Airlines flight hit

by severe turbulence last week showed a rapid change in

gravitational force and 54 metre altitude drop caused injuries,

Singapore's transport ministry said on Wednesday.

One passenger died of a suspected heart attack and dozens

were injured after Singapore Airline Flight SQ321, flying from

London to Singapore, encountered what the airline described as

sudden, extreme turbulence while flying over Myanmar. The

ministry said the investigation was ongoing.