"We underestimated the engine problems," Enders told the Sunday newspaper Bild am Sonntag.
At the start of the programme, Airbus had "let itself be persuaded by some well-known European leaders into using an engine made by an inexperienced consortium," Enders said.
Furthermore, it had let itself be roped into assuming full responsibility for this new type of turbo-prop engine, he continued.
"These are two massive problems which we're now paying for."
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Despite delivery delays and limitations in its operational readiness, Enders said governments should not start looking for alternatives.
"To write off the A400M would be the biggest mistake, because this plane has enormous potential," Enders said.
One day, the new transporter would "form the backbone of the European transporter fleets" and would be an exporting success, he argued.
The A400M is to replace the German army's ageing Transall aircarft.
The new military transport was commissioned jointly in 2003 by the governments of Germany, Belgium, France, Britain, Luxembourg, Spain and Turkey.
And new faults were discovered in the propellor engines earlier this year.