All 14 of the French air force's Lockheed Martin C-130H/H-30 Hercules have been grounded since 18 October following maintenance problems.
Portugal's state-owned OGMA military maintenance company won a six-year contract for the aircraft in June, beating incumbent French company Sogerma to the deal.
OGMA says it "recognises that there were difficulties at the beginning of the contract, mainly due to the short transition period for this agreement". It adds that it has taken several measures to "rapidly improve the situation", including a partnership deal with Lockheed Martin "for the supply of all necessary parts".
OGMA says: "The recovery plan is in place and results are expected within the very near-term, starting with an increased fleet availability this week."
Portuguese defence minister Paolo Portas announced last week a €50 million ($49 million) loan to OGMA. Company president Miguel Morais Leitao says: "This loan will not solve OGMA's problems, but it's a first step."
The air force says the problem is "certainly transitory".
Source: Flight International