However, deliveries of the world's largest turboprop engines for the Airbus plane have not been delayed as a result of the problems found during production at a parts supplier, Philippe Petitcolin, chief executive of France's Safran (>> SAFRAN), said.

Airbus Group (>> Airbus Group) said on Friday it was sticking to plans to deliver 20 of the European NATO transporter planes this year as it urged the four-nation engine consortium to fix problems in the propeller gearboxes.

It said two separate problems had been identified, requiring the aircraft to undergo regular inspections and to have parts replaced if necessary, but not forcing them to be grounded.

The A400M is powered by two pairs of turboprop engines whose propellors rotate in opposite directions, requiring two different versions of the gearbox.

Only one pair of engines is affected by the problems, which were discovered during production, Petitcolin said.

"There is no problem in the short term, but it affects reliability in the long term. It is being fixed," he said.

Asked how long it would take to resolve the problems, he said, "It's between several weeks and several months".

"There are no delivery delays today," he added.

The gearboxes are made by Italian supplier Avio Aero, owned by General Electric (>> General Electric Company) of the United States.

In an emailed statement, Avio Aero said its engineers were "fully engaged" with the consortium of engine suppliers and Airbus Defence & Space in investigating the problems.

Besides Safran, the engine consortium includes Rolls-Royce (>> Rolls-Royce Holding PLC), Germany's MTU Aero Engines and ITP of Spain.

Petitcolin was speaking on the sidelines of a ceremony at a Safran military plant to mark the signature of a 300 million-euro contract awarded by the French government for 14 tactical Patroller drones.

Safran beat rival Thales' (>> THALES) Watchkeeper system after a fierce competition earlier this year.

(Reporting by Cyril Altmeyer; Writing by Tim Hepher; Editing by Greg Mahlich)

By Cyril Altmeyer