The run of technical problems for Australia's Qantas Airways continued Sunday with a Singapore-London flight landing in Frankfurt after the captain of the Boeing 747-400 decided to shut down one of the engines, reported dpa. A Qantas spokeswoman said a vibration had developed and "as is standard procedure, the engine was shut down." The 350 passengers were put on other flights. "There was no safety issue at any time and the aircraft continued to Frankfurt, where it landed without incident," she said. Last week a faulty rudder delayed a plane from London for 15 hours and an internal flight was forced into an unscheduled landing because ground crew had forgotten to empty its toilet tanks. Two weeks ago engineers in Singapore discovered a body panel had fallen off a Qantas jumbo flying in from Melbourne. Australia's aviation safety watchdog, the Civil Aviation Safety Authority (CASA), is investigating the run of technical hitches. CASA said on Friday that the initial finding that an exploding oxygen cylinder had forced a Qantas jet to make an emergency in Manila on July 25 had been correct. The oxygen tank in the cargo bay punched a 3-metre hole in the fuselage of a 747-400 flying from Hong Kong to Melbourne, forcing the pilot to descended from 29,000 feet to 10,000 feet in about five minutes and make an emergency landing in Manila. A week after Qantas' Manila scare a domestic flight was forced to return to Adelaide after a wheel bay door on a Boeing 767 failed to close properly. Just days after that, a flight bound for Manila returned to Sydney after the pilot declared an emergency and dumped fuel because of a leak in the hydraulics operating a wing flap.