Boeing has agreed to pay Spirit AeroSystems up to $350 million in advance to keep producing products for it as the fuselage supplier works through a liquidity crunch. The jet maker said Tuesday that the advance payments are intended to help Spirit address high levels of inventory and lower operational cash flows.

One week after Spirit AeroSystems announced it has "substantial doubt" about its ability to continue as a going concern, Boeing is offering help.

Spirit Aerosystems (NYSE:SPR) rose 1.6% after the company confirmed that it entered into an advance payments pact with Boeing (BA). Boeing (BA) committed to pay as much as $350 million in the advanced payment pact,