A second RAF aircraft has left Paris with supplies and personnel to help the French military mission against rebel forces in Mali, the MoD has confirmed.
The C17's departure had been delayed to allow parts to be flown in from the UK to fix a hydraulic problem.
Another C17 carrying supplies has already landed in Mali.
Prime Minister David Cameron's decision to offer "limited" logistical support to France has been endorsed by the UK's National Security Council.
The C17s will carry military equipment such as French armoured vehicles and help transport servicemen and women to Mali.
French military officials insisted on Tuesday that the central town of Konna was not back in Malian control, contradicting state reports at the weekend.
Defence minister Jean-Yves Le Drian said air strikes by French forces had blocked the rebel advance, forcing them to withdraw into an area between Douentza and Gao.
But he insisted Konna has not yet been recaptured.
The four-engine jet left RAF Brize Norton in Oxfordshire on Sunday, but was grounded at the Evreux-Fauville airbase until Tuesday to allow the "minor technical fault" to be fixed.
After a meeting of the NSC on Tuesday, Mr Cameron's spokesman said: "The NSC agreed that our approach is the right one, which is logistical support to the French through airlift capability and the sharing of any intelligence that we may have, and continued diplomatic efforts with our international partners at the UN and elsewhere."
On Monday, Mr Cameron insisted no UK ground troops would be deployed to the conflict in Mali, where French forces are fighting Islamist rebels.
Meanwhile, defence minister Andrew Robathan told the House of Commons that the RAF's involvement in operations should only last a week and there were no plans to commit "further resources".
French troops began to attack the militants on Friday, as part of efforts to support Mali's government until an African force is able to take over.
French defence military officials said about 800 soldiers had been deployed in Mali, with a further 1,700 expected to arrive in the coming days.
A convoy of 40 to 50 trucks was en route to Mali from Ivory Coast to help French forces.
Nigeria has pledged to send 900 troops, with the first 200 arriving in Mali by Wednesday night.
President Francois Hollande insisted on Tuesday he had no desire for French troops to remain in Mali in the long term.
He said: "We have one objective - to ensure that when we leave, when we end our intervention, Mali is safe, has legitimate authorities, an electoral process and there are no more terrorists threatening the territorial integrity of Mali."