Now a panel falls off a Qantas jet bound for London

The embarrassing malfunction was the latest in a string of incidents for the airline.

Inspectors conducting a routine check in Singapore on the Boeing 747-400 noticed the small panel had become detached, a Qantas spokeswoman said.

"This had absolutely no flight safety implications," said the spokeswoman, who spoke on condition of anonymity, as is customary.

A Qantas plane takes off at the airport in Sydney earlier this month

The panel - which is used by engineers to access various parts of the engine for inspections - was replaced, and the flight continued on to London after a delay of about six hours.

Australia's Civil Aviation Safety Authority spokesman Peter Gibson said planes are not affected if the panels detach, noting that it's "quite legal" to continue flying without them.

The force of air can sometimes pull the panels off if an engineer hasn't latched them tightly enough, he said.

The airline has been plagued by problems since an explosion on one of its planes forced an emergency landing in Manila last month.

Since then, another plane was forced to return to Adelaide because of an issue with its landing gear, and a Boeing 767 returned to Sydney soon after takeoff when air traffic controllers saw fluid streaming from a wing.

On Wednesday, one of four engines on a Boeing 747-300 from Melbourne was "reduced to idle" speed as the plane approached Auckland Airport in New Zealand, a Qantas spokeswoman said.

The pilot managed to land the aircraft with 219 passengers and 16 crew safely.

Also Wednesday, the safety authority said it would expand its investigation of Qantas after the airline announced it temporarily pulled six planes from service because of irregularities in maintenance records.

Qantas said it was a record-keeping issue and there were no safety implications for the aircraft.