Airbus President and Chief Executive Tom Enders on Monday showed a picture at the Dubai Airshow of the A400M he said was taken the night before. It showed the inboard, port side propeller spinning rapidly.

Enders said each of the engines was run Sunday night outside the final assembly line in Seville, Spain, and will be tested together next week.

"What that means (is) that we are in serious countdown mode for (the) first flight," he said.

Enders declined to say when exactly when the hulking aircraft would first take to the air. But he reiterated Airbus' plan to test fly the plane before the end of the year.

"Certainly before Christmas, this bird should take to the skies," he said.

Last Friday, the France-based plane maker said it had moved the prototype from the factory for final ground tests.

Those tests include running up problem-plagued turboprop engines to full power, low- and high-speed taxiing, and aborted takeoffs designed to check all aircraft systems before the first flight, a spokeswoman said last week.

The A400M program was launched in 2003 with an order for 180 planes from seven countries: Belgium, Britain, France, Germany, Luxembourg, Spain and Turkey.

Defense ministers from those nations agreed to re-negotiate the contract on the 20 billion euro ($29 billion) multinational project earlier this year amid cost overruns and delays blamed in part on the new Europrop International TP400 engines.

The A400 is designed to replace smaller Lockheed C-130 Hercules and Franco-German Transall C-160 transports in Europe. It could also compete against U.S. made C-130s and the larger Boeing C-17 both on the continent and in overseas export markets.