16 Qantas domestic flights cancelled

Qantas has cancelled 16 domestic flights today, with the airline blaming maintenance engineers for having to ground five planes as its dispute with pilots escalates.

It comes as engine trouble forced a Sydney-bound flight to turn back to Bangkok while Qantas faced criticism for losing track of an unaccompanied child.

Scrapped flights tally

Sixteen domestic flights were cancelled today as the airline grounded five of its aircraft, saying there was a maintenance backlog following disruptions caused by rolling strike action by engineers.

Qantas will cancel 400 flights over the next month, citing ongoing industrial action by the Australian Licensed Aircraft Engineers Association.

The ALAEA last week said it would not take further action until after the airline's annual general meeting on October 28.

The airline is battling union disputes on three fronts, with engineers, ground staff and pilots all stepping up their campaigns for better pay and conditions.

Today, pilots came out swinging against what they claim is Qantas's decision to walk away from conciliation talks before Fair Work Australia.

The Australian and International Pilots Association has ruled out taking strike action, but it has slammed the airline and urged it to return to negotiations.

"(Qantas) are clearly committed to aggravating and exacerbating this dispute and Australians deserve to know why," AIPA president Barry Jackson said in a statement.

Qantas spokeswoman Olivia Wirth says the pilots' claims are unreasonable.

"We are very much committed to these negotiations, however this one claim makes it very difficult for negotiations to make any headway and make any progress," she told ABC radio.

There was more negative publicity today after it emerged a Qantas flight from Bangkok to Sydney had to turn back after passengers heard a bang and the plane vibrated.

The pilot shut down one of the four engines and the plane landed back in Bangkok shortly before 11pm (AEDT) on Sunday with no further incident.

Meanwhile, the airline admitted it lost track of an unaccompanied 11-year-old boy and misplaced the paperwork involving his flight to Hobart.

The boy was forced to wander around Hobart Airport on his own late at night on September 28 after getting off a flight from Melbourne, Fairfax newspapers reported.

Qantas said the incident happened during a particularly busy night when the arrivals hall of Hobart Airport was in turmoil because storms in Melbourne had caused flight delays, passenger disruption and lost baggage.