A Qantas jetliner that was damaged by a midair explosion in July collided Tuesday with another of the airline's planes on an Australian airport tarmac, airline officials said.

Both Boeing 747 jets were damaged when they ran into each other while being towed at the Qantas maintenance base at Avalon Airport outside Melbourne, Qantas general manager of engineering David Cox said in a statement. No passengers were aboard.

Television news footage showed that the nose of one of the jets hit the left wing of the other. The nose cone caved in and the wing had a large dent.

"Both aircraft sustained some damage, and the extent of this is being assessed," Cox said.

The maintenance staff involved had been suspended from duty pending a full inquiry, he said. Qantas has not said how many personnel were involved.

On July 25, an oxygen tank exploded aboard one of the jets, ripping a hole in the fuselage and causing rapid cabin decompression as the plane flew over the South China Sea. None of the 365 people aboard was injured and the pilot safely made an emergency landing in Manila in the Philippines.

The jet was repaired in Manila and only returned to Australia last week, a spokesman said, on the company's usual condition of anonymity.

It was undergoing final maintenance work at Avalon, Qantas' maintenance base for 747s in Australia before returning to service, the spokesman said.

The collision is the latest in a series of accidents and malfunctions in recent months that have embarrassed Australia's' flagship carrier and have raised questions about its maintenance standards.