Australian flag-carrier Qantas has said it cannot give any definite time frame as to when its fleet of six Airbus A380s will take to the skies again as it continues to carry out safety checks. Last week, one of the airline’s superjumbos experienced engine failure due to an explosion, forcing it to request an emergency landing at Changi Airport in Singapore.

Alan Joyce, Qantas’ chief executive, has since said that oil leaks found in three other Airbus engines have been discovered. Until the cause is fully understood, the airline will ground its fleet. Initially, the safety checks were expected to have been completed by yesterday.

Europe’s Aviation Safety Authority has told all airlines running aircraft with the Rolls-Royce Trent 900 engine to conduct thorough safety checks. The airline safety body said the most likely cause for the Qantas engine malfunction was a fire sparked by an oil leak.

Alan Joyce admitted that it was worrying to discover oil where it shouldn’t have been, especially considering that the Rolls-Royce manufactured engines were only a couple of years old. Qantas said it was currently amending its flight schedule to fit with the fact that it is not currently able to use its superjumbos.

Other carriers using the Trent 900 on their A380s include Singapore Airlines and Lufthansa. The German carrier said it was able to carry out the necessary checks on its planes without disrupting schedules. Singapore Airlines said it would be replacing three of its Trent 900s as a purely precautionary measure.