Qantas has suffered its third emergency scare in a fortnight after one of its 747s was forced to return to base mid-flight after the cockpit filled with smoke.

Pilots on the flight from Sydney to Buenos Aires were forced to wear oxygen masks and dump fuel over the Pacific Ocean before making a ‘priority landing’.

The incident is the third emergency that Qantas has suffered in the past fortnight, including the engine explosion of an Airbus A380, which led to the Australian flag carrier grounded all six of its fleet of superjumbos.

The latest incident is believed to have been caused by a faulty instrument panel.

The airline said the 747 was carrying 221 passengers and crew.

Passengers said the pilot informed them that there had been a problem with an instrument panel in the cockpit and the plane would return to Sydney.

Qantas spokesman Olivia Wirth said the passengers would be put on alternative flights.

She confirmed the “minor electrical fault” caused a “minimal” amount of smoke in the cockpit. No smoke entered the passenger cabin.

On Friday, a Qantas Boeing 767 was also forced to turn back on a domestic flight after pilots detected abnormal vibrations in one of its two General Electric engines.

And the week before, a Sydney-bound Qantas Boeing 747 landed safely in Singapore after an engine caught fire shortly after takeoff.

The A380 incident is being blamed on a fault in the Rolls-Royce Trent 900 engine, which led to leaking oil catching fire. This led to disintegration of metal parts of the engine. These also flew off and damaged vital systems in the wing, causing the pilots to lose control of the second engine and half of the brake flaps on the damaged wing.

Investigations by Qantas also revealed suspicious oil leaks in three engines on three different grounded A380s.

Singapore Airlines and Lufthansa, which both use A380s with Trent 900 engines, have conducted checks on their superjumbos and all but one have returned to service, the airlines say.

However Qantas’ A380s - the core of its lucrative international routes between Australia and Los Angeles, Singapore and London - remain grounded despite what experts say is financial pressure to fly them again.

“We are taking our normal and extremely conservative approach to safety and will not operate our A380 fleet until we are completely confident that it is safe to do so,” Simon Rushton, a Qantas spokesman, said.
Qantas was still hopeful of returning the A380s to service “in days, not weeks,” he added.

Engine manufacturer Rolls-Royce said that it would be replacing a collection of linked parts, on the Trent 900.

Airbus said Rolls-Royce would also be equipping the engines with software to shut them down before an oil leak could cause an engine to disintegrate.