(Adds Airbus C295 refuelling trials, last 2 paragraphs)
By Sabine Siebold and Andrea Shalal
BERLIN, Oct 5 (Reuters) - Germany is looking at buying 4-6 new Lockheed Martin C-130J troop transport planes and operating them jointly with France, placing a further dent in plans for a fully European airlift capability based on the delayed A400M.
German Defence Minister Ursula von der Leyen and her French counterpart, Jean-Yves Le Drian, signed an agreement in Paris late on Tuesday to study a joint tactical airlift pool of C-130J aircraft, the German defence ministry said.
The latest initiative in Franco-German defence co-operation comes against the backdrop of tough negotiations with Airbus Military over delays to the A400M, as well as growing European concerns over a possible shift in UK defence priorities away from its continental partners following the Brexit vote.
France is already in the process of buying four C-130J aircraft from Lockheed partly to allow refuelling of helicopters used by its special forces, a feature originally meant to be supplied by the A400M but abandoned for technical reasons.
"We expect considerable synergies from such a move," Markus Grubel, parliamentary state secretary in the German defence ministry, told lawmakers in a letter about the C-130J purchase.
There has been speculation that Germany could buy used C-130J aircraft from Britain to help meet near-term needs.
But a German defence ministry source said Berlin would buy up to six new aircraft directly from the United States.
Such a deal could be worth close to half a billion euros, based on the 330 million euros ($370 million) budgeted by France for its earlier purchase of four C-130Js.
"Current plans call for the procurement of new aircraft. There are no specific timelines for that purchase," a defence ministry source said.
The German-French agreement foresees the new joint tactical airlift capability being operational by 2021, but it is not certain Germany will have all its C-130Js by then.
Von der Leyen told Reuters last week Germany would make a decision soon on acquiring C-130s to cover what Berlin views as a gap in capabilities once the elderly Transall leaves service in 2021.
Germany is the largest customer for the A400M, initially developed for seven European NATO nations at a cost of 20 billion euros but mired in delays and heavy cost overruns.
Airbus declined to comment on Germany's C-130 proposals, but sought to dampen the political attention being given to its rival warplane by announcing separately that it had carried out successful trials of its C295 turboprop as a refuelling tanker.
The company, partly owned by the French and German governments, had lobbied France in vain to reject the C-130 for its special forces and to take the Spanish-built C295 instead.
$1 = 0.8921 euros Additional reporting by Tim Hepher; Editing by Elaine Hardcastle and Mark Potter