FILE PHOTO: The logo of Airbus is pictured at the Airbus A330 final assembly line at Airbus headquarters in Colomiers, near Toulouse, France, November 26, 2018. REUTERS/Regis Duvignau

BERLIN (Reuters) - The fatal crash of a German armed forces helicopter in Mali last year was caused by the failure of mechanics from manufacturer Airbus to correctly set the aircraft’s rotor controls after repairs, a defense official told Reuters on Wednesday.

An armed forces investigation of the crash, which killed both pilots aboard the helicopter, found that neither a technical defect nor material fatigue were to blame, according to the official who has seen the report and a second source briefed on the matter.

“It was a maintenance error on the part of Airbus. The pilots were not at fault,” said the second source.

Airbus said in a statement that a German military investigation had identified an improper setting of controls as “one of the factors in the chain of events” that led to the crash, and precautionary measures had been implemented to prevent any reoccurrence of the issue.

It said the investigation had ruled out any design issue with the Tiger helicopter. The company said it would refrain from further statements due to pending proceedings on the case.

“Airbus must take responsibility,” said Agnes Strack-Zimmermann, deputy head of the Free Democrats and defense spokesperson for her party.

The Tiger helicopter had been deployed to support a peacekeeping mission in Mali’s desert when it lurched into a steep, uncontrolled forward dive so severe that the rotors fell to pieces during its rapid descent.

The report found that Airbus mechanics had incorrectly calibrated the Tiger helicopter’s rotor controls after repairs carried out at its home base of Fritzlar in central Germany.

The two highly experienced pilots, subjected to enormous G-forces during the plunge, had no chance of correcting the stall, the official said, speaking on condition of anonymity due to the sensitivity of the matter.