THIS dramatic picture shows damage caused when a Rolls-Royce engine failed in mid-air.

It reveals a hole torn in the Qantas airlines flight from San Francisco to Sydney, which had 212 passengers and 18 crew members on board.

It had to turn back shortly after take-off when the Rolls-Royce RB211 engine, which was developed in Derby, developed a mechanical fault.

Reports of the incident on Monday said passengers saw flames and sparks flying out of the engine.

The pilots dumped fuel before making an emergency landing at San Francisco.

A Rolls-Royce spokesman said last night it was helping the airline with its investigation.

He said: "It would not be appropriate to go into any further details while an investigation is still being carried out."

Meanwhile, it has also emerged that Rolls-Royce RB211 engines were the subject of a safety warning from the American-based Federal Aviation Administration last month.

An "airworthiness directive" was issued which said that "several low pressure turbine shafts had been found with cracks originating from the rear cooling air holes" in a number of Rolls-Royce RB211 engines.

Due to take effect from September 27, it calls for airlines to inspect blades for cracks during the next scheduled maintenance visit.

It says the cost of replacing parts, if found to be faulty, would be £10,000.

However, it is understood the information in the directive was first issued by another authority more than two years ago.

It is also understood that the type of RB211 engine that developed a fault on the Qantas flight was not affected by the safety bulletin.

David Learmount, safety editor of aviation website Flight Global, said about 100 directives were issued globally every day and were a "preventative" measure.

"It is not a major problem," he said. "Airworthiness directives are put out when a fault is found and it advises anyone else using the same part to carry out an inspection. It's basically saying 'someone else had a problem, why don't you avoid it by checking to see if it is down the line'?

"This is simply a very effective safety system. There might be a directive about a radio set which keeps getting short-circuits and issues electrical heat smells."