The discovery also prompted the Federal Aviation Administration in Washington to announce plans for similar inspections on Boeing 747s in the United States.
It has been reported that lines had to be replaced on eight of the Lufthansa’s 747-400 models, and all the jets later were returned to service.
The cracked lines were discovered early in the day during routine maintenance of one of the 747-400s, and Lufthansa decided to ground all the aircraft until they were inspected and their copper lines replaced.
A Boeing spokesman has said that he was unaware of other airlines reporting
similar problems, adding that fires in the turbine engines were rare but that the lines in question were critical to dousing any blaze.
In Seattle, Boeing spokeswoman Debbie Nomaguchi said the company issued a service bulletin for the same fire-extinguisher tubing in 1995, advising airlines flying 747-400s to replace it because of problems similar to those reported by Lufthansa.
MAS should explain whether it is grounding its Boeing 747-400 planes for safety inspection as Boeing is not certain whether this is an isolated case or if it's fleet-wide affecting all 747-400s.