Qantas explosion: What we know so far

An airplane's engine 'exploded' shortly after takeoff at Sydney Airport forcing an emergency landing and possibly sparking a massive grassfire.

It's understood Qantas flight QF520 had just taken off from Sydney to Brisbane shortly before 1pm when one of the engines failed and passengers heard a loud 'bang'.

The plane was forced to circle Botany Bay before making an emergency landing with all 174 passengers disembarking safely.

Around the same time, a huge grass fire started near the airport's third runway in the vicinity of Sir Joseph Banks Park. It is not known whether the two incidents are linked.

Huge clouds of smoke could be seen billowing above the airport as NSW Fire Service crews fought to get the blaze under control.

All flights in and out of the airport have reportedly been halted while fire crews battle the blaze.

Qantas Chief Pilot Captain Richard Tobiano said the plane suffered a 'suspected engine failure after take-off'.

'Our pilots are highly trained to handle situations like this and the aircraft landed safely after the appropriate procedures were conducted,' Mr Tobiano added.

'We understand this would have been a distressing experience for customers and we will be contacting all customers this afternoon to provide support.'

The airline has launched an investigation into what caused the incident.

A Sydney Airport spokesperson said their 'priority is to conduct a full inspection of its parallel runway and to return it to service as quickly as possible'.

'Sydney Airport's main runway is operational, however, passengers should also expect some delays and we thank everyone for their patience,' they added.

Georgina Lewis, a producer for the Today Show, was one of the passengers on board the flight.

'We had just taken off when we heard a bang. One of the engines appeared to have failed,' she told Channel 9.

'There was silence on board and for a while it felt like we weren't gaining much altitude.

'There were some worried looks throughout the cabin.

'About ten minutes later, the pilot came on to reassure us about safety, explaining that they'd had an issue with the right engine on takeoff and had to shut it down for safety reasons.

'I assume they then needed to notify everyone on the ground.

'So, we circled south of Sydney over the water for quite some time until we were finally able to land safely on one engine—there was a lot of cheering on board, I can tell you that.

'I'll be honest—I have a fear of flying, so this was not my happiest moment in the air when I heard that loud bang.

'But I'm just so grateful we're back on land. Kudos to Qantas for their handling of the situation.'

A Sydney Airport spokesperson said the Brisbane-bound flight was forced to make 'an emergency-return to Sydney Airport, landing safely just after 1pm'.

'This departure of aircraft coincided with a grass fire along the eastern side of the airport's parallel runway, which was brought under control by teams from the Aviation Rescue Fire Fighting Service,' they added.

'It's not clear at this stage if the two incidents are linked and investigations are continuing.'

The spokesperson said passengers should expect delays while they ensure the runway is safe to resume flights.