Airbus’ long-suffering A380 superjumbo suffered another blow after Qantas Airways formally cancelled an outstanding order for the out-sized aircraft whose future is once again on the line.

The Australian airline, one of the initial operators of the double-decker plane, scrubbed an order for eight aircraft, which has a list price in excess of $445 million.

Sydney-based Qantas had been pushing back the 2006 commitment for the Airbus aircraft for years. In a statement Thursday, Qantas, however, said it will upgrade its existing fleet of 12 A380s, starting this year.

“These aircraft have not been part of the airline’s fleet and network plans for some time,” Qantas said in its statement, referring to the 2006 order.

The formal scrapping of the order puts the future of the flagship program in further doubt. Gulf carrier Emirates, the primary operator of the superjumbo, may convert some or all of its most recent 20 orders for the jet into smaller A350s, people familiar with the matter have said.

That switch would slash Airbus’s order backlog of its largest passenger aircraft.

Qantas has had a fractured relationship with the A380. The airline made global headlines in late 2010, when an A380 en-route from Singapore suffered a mid-flight engine explosion that ripped through the wing, though the aircraft returned to the airport safely and nobody was seriously hurt.

Qantas grounded its fleet of A380s for a few weeks immediately after the incident.

For all its imposing size and commanding presence in the skies, the A380 hasn’t managed to leave much of an imprint with most airlines, relegated instead to an afterthought for carriers who built their stables around nimbler planes.

Since entering commercial service a decade back, the A380 has faced an ever-shrinking fan base. Passengers love the plane for its modern layout, perks like spacious bars in business class and even enclosed cabins and showers in some first-class offerings, but airlines have been much harder to win over.

Some early prospective customers dropped out, others scaled back their order book.

Only Emirates became a true champion of the A380, building a large part of its globe-spanning fleet around the plane, with already more than 100 in operation.