SQ32I injuries likely caused by 54m drop in 4.6sec: Investigators

Preliminary analysis points to rapid changes in gravitational forces in those few seconds

- Mike Yeo

Over 4.6 seconds on May 21, Singapore Airlines flight SQ321 dropped 178 feet, or about 54m, which wreaked havoc in the plane cabin and likely caused the injuries to cabin crew and passengers.

The Boeing 777-300ER had encountered rapid changes in gravitational forces (G-forces) in those few seconds, which resulted in the drop in altitude, according to the findings of a preliminary investigation issued on May 29.

Investigators from the Transport Safety Investigation Bureau (TSIB) set out a timeline of the incident, based on a preliminary analysis using the data stored in the flight data and cockpit voice recorders.

Their initial findings showed that passengers had only eight seconds to react after pilots turned on the "fasten seat belt" sign before the aircraft was hit by severe turbulence, which injured dozens of people and claimed the life of a 73year-old British man.

The TSIB investigates air, marine and rail accidents, and is part of the Ministry of Transport. The SQ321 investigation team comprised TSIB investigators and representatives from the United States' National Transportation Safety Board, Federal Aviation Administration and aircraft manufacturer Boeing.