"In some capabilities we are late at our end. On the other side, the acceptance process with customers is pretty painful," Harald Wilhelm told journalists after including a caveat on the aircraft in Airbus' quarterly results.

"Given our past history on it, the objective remains to avoid any incremental charge, but we are on the way to assessing it. If you ask me whether I can exclude it, I cannot say that this is the case, so it's work in progress."

He also said Airbus had recently put a brake on plans to sell part of its stake in French planemaker Dassault Aviation due to market volatility and may now wait until 2015.

"The last weeks in terms of market volatility were probably not the best ones to bring the stock to market," he said on a conference call.

"That's why we will look for better windows. In other words, there would have been a chance that it would have been in the market already, so we will watch out for the next windows to come. There are not many left before the end of the year, so don’t be surprised therefore if it falls in 2015."

He reported "good progress" in talks with Dassault and the French government on the future of the 46.3 percent stake.

(Reporting by Tim Hepher, Cyril Altmeyer; Editing by James Regan)

Stocks treated in this article : AIRBUS GROUP, DASSAULT AVIATION