Sydney: A bird and a bolt of lightning were the latest problems to strike Qantas, the airline said Wednesday, causing the fourth flight turnaround since an engine blowout on one of its Airbus superjumbos caused a global safety scare.

The string of incidents on Qantas' older fleet of Boeing planes is unrelated to the A380 scare and were caused by various glitches and uncontrollable events that are not uncommon to any major carrier, the airline and a commercial aviation analyst said. But they were drawing extra attention following the superjumbo blowout.

In the latest incident, a Boeing 747 carrying 171 passengers bound for Sydney turned back to Johannesburg after a bird slammed into one of the jumbo's four engines shortly after takeoff late Tuesday, Qantas spokesman Tom Woodward said. It landed safely, but suffered damage to turbine blades in one engine that would take a day or two to repair, he said.

Also on Tuesday, a Qantas Boeing 717 sustained minor damage to its fuselage when it was struck by lightning during a domestic flight between the Outback cities of Alice Springs and Darwin. The plane did not have to turn back because of the strike, and continued safely to its destination of Darwin, Woodward said.

Four Qantas flights have turned back to port since the A380 incident because of various faults and problems. The airline says none of them were as serious as the superjumbo problem, and the turnarounds were in line with Qantas' routine safety procedures.

The day after the A380 problem, a Qantas Boeing 747 bound for Sydney turned around and landed safely in Singapore after an engine caught fire minutes after takeoff. Last Friday, a Boeing 767 turned back on a domestic flight in Australia after pilots detected abnormal vibrations in an engines.

On Monday, the flight crew aboard a Qantas Boeing 747 bound for Argentina donned oxygen masks and returned to Sydney after an electrical fault sent smoke into the cockpit.

Peter Harbison, the head of the respected consultancy the Center for Asia Pacific Aviation, said the various problems Qantas flights have experienced since the A380 incident are the kind of things that all airlines experience from time to time.

"None of them is uncommon in its own right, though it is relatively uncommon to have such a string of them so quickly, with no common cause," he said. "It's just one of those times - when you're unlucky, you're unlucky."
Extra attention has focused on Qantas - which has a reputation as one of the world's safest airlines - since the Nov. 4 A380 incident, when one of the plane's four Rolls-Royce Trent 900 engines disintegrated in flight and sent shrapnel ripping through the wing before it returned to Singapore and landed safely.

Aviation officials have identified an oil leak near a turbine as the flaw that caused a fire and the engine failure, and Qantas' six A380 - the world's largest passenger plane - remain grounded while the airline carries out checks and repairs. The other carriers using Trent 900s on their A380s, Singapore Airlines and Lufthansa, have returned their planes to service.