The CEO of Qantas Airlines has announced that the company’s fleet of Airbus A380 planes will remain grounded for at least another 3 days.

Alan Joyce said the planes will not be returning to service until they can be 100 percent certain of the safety. In the investigation, three of the planes were discovered to have oil leaks beyond the normal tolerances according to Joyce and this continues the investigation.

He said the engines have been removed from the planes and are currently being examined by Rolls Royce, the maker of the engine.

The engine manufacturer has also made an announcement regarding the plane engines it produces.  Rolls Royce has announced that it has made progress on understanding the cause of the engine failure on Thursday’s flight and has determined the incident to be specific to the Trent 900 engine.

There have been a series of checks and inspections agreed to between the engine manufacturer, Airbus, the operators of the Trent 900 powered A380 and the airworthiness authorities.

Rolls Royce said they would issue a further update on November 12.

The investigation stems from an incident Thursday in which a Qantas flight was forced to return to Singapore’s Changi Airport shortly after take-off. The plane experienced engine failure and part of the cowling, or covering, to the engine fell from the plane. This led to Qantas grounding all A380 planes in its fleet.

The grounding of the planes left 500 residents temporarily stranded in Los Angeles, California over the weekend. The airline paid for hotels, expenses and phone calls and has announced there would be further compensation. It was believed that the last of those stranded would be out of Los Angeles on Monday.