* Air force has 53 on order, taken deliver of 31
* Airbus says issues raised not safety critical
* Luftwaffe says aircraft cannot perform all tasks (Adds Airbus statement)
BERLIN, Nov 13 (Reuters) - Germany's air force said on Wednesday it had decided not to accept delivery of two Airbus A400M planes, citing recurring technical problems with the military transporters.
The air force said the A400M had taken part in nearly 1,700 missions and formed the backbone of its air transport for carrying personnel and material, air-to-air refuelling and humanitarian aid missions.
Although 31 aircraft of 53 ordered had been handed over, it said there were technical issues with the planes, including with nuts used on propellers. It said extra time was needed for inspections that undermined the readiness of the A400M fleet.
Airbus said in a statement that issues with the model were not safety critical.
"We are aware of findings related to dowel bolts/Propeller interface in some of our customer aircraft," it said. "This is not safety critical and our customers continue to accept and operate their aircraft."
It said it was working both with Europrop International (EPI), the consortium responsible for providing the troop carrier's turboprop engines, and Ratier-Figeac, the French company that makes the propellers, to alleviate the need for inspections.
The German air force said extra inspections were also needed to test engine mounts, combustion chambers and engine flaps and for crack detection on various parts. It said the A400M was still not able to perform all tasks, despite these checks.
"The overall technical defects and the realisation that the two planes due to be delivered also do not possess the characteristics that were guaranteed in the contract, have resulted in the armed forces not taking these aircraft," the Luftwaffe, or air force, said in a statement.
The A400M was commissioned in 2003 to give Europe an independent airlift capacity to support military or humanitarian missions, rather than relying on the Lockheed Martin C-130 or the now out-of-production Boeing C-17.
A 3.5-billion-euro bailout from Belgium, Britain, France, Germany, Luxembourg, Spain and Turkey rescued the A400M programme from cancellation in 2010 after delays and cost overruns. (Reporting by Sabine Siebold; Writing by Michelle Martin; Editing by Madeline Chambers and Edmund Blair)