The plane was waiting to leave for Osaka, Japan, from Tan Son Nhat Airport on August 21 when the driver of the vehicle towing the ramp apparently lost control and struck it, leaving a 20cm x 20cm hole on its fuselage.
The ramp was managed by the Vietnam Airport Ground Services Company Limited.
The flight had to be postponed by a day and the aircraft has been sent for repairs and checks.
The Southern Airports Authority (SAA) and other relevant agencies have asked the driver and other personnel for a report.
The driver, who has not been named, said the vehicle "suddenly shifted gears" and crashed into the plane.
He did not test positive for alcohol, the SAA said.
As of Tuesday the repairs have not been completed.