The Airbus A400 military transport aircraft crash last month was caused by faulty software configuration that froze three engines, the company published details of the investigation on Wednesday.
The initial findings of the crash released by Airbus officials confirmed that the erroneous engine control system software may have caused the engine to freeze but ruled our structural design flaws.
The A400M, designed as a troop and heavy cargo carrier for a group of European NATO nations, crashed shortly after takeoff on a test flight on May 9, killing four out of six crew.
The aircraft was being prepared for delivery to Turkey.
Airbus said 'black box' data and cockpit recordings indicated that three out of four of the plane's turboprop engines became stuck at high power shortly after takeoff.
At first, the three affected engines "did not respond to the crew’s attempts to control the power setting in the normal way," Airbus said in a statement.
A spokeswoman said investigators were looking mainly at "the different processes around the assembly of the aircraft, the engines and the preparations for first flight".
Investigators have found that all other systems worked correctly, Airbus said in a bulletin to the plane's operators.
On May 19, Airbus asked nations that have taken delivery of the A400M - Britain, France, Germany, Turkey and Malaysia - to carry out checks on the 'Electronic Control Unit,' part of the digital system used to control the West's largest turboprop engines. Other buyers include Belgium, Luxembourg and Spain.