By David Shepardson, Allison Lampert and Tim Hepher (Reuters) -Spirit AeroSystems said on Tuesday it would receive up to $350 million in advance payments from its largest customer Boeing, giving the struggling supplier a lifeline as it burns cash after four consecutive years of losses.

Boeing has agreed to loan aerostructures manufacturer Spirit AeroSystems up to $330 million, a move coming just days after Spirit warned that a cash crunch threatened the viability of its business.

In April, Boeing provided a $425 million advance to support Spirit's liquidity. Spirit, Wichita's largest employer with around 12,800 full-time workers, previously disclosed it has spent all of that money, as well as the entirety of a $350 million bridge loan that was set up earlier this year.

Spirit AeroSystems said Tuesday that planemaker Boeing will pay up to $350 million in advance payments to the firm, providing the struggling supplier a lifeline as it continues to burn cash after four consecutive years of losses.

The payments are intended to help address high levels of inventory and lower operational cash flows.

Spirit said this week it is seeking ways to raise liquidity including possible customer advances. The supplier has previously disclosed it has drawn down a $350-million bridge loan set up when Boeing agreed to acquire the supplier, and previous advances from both the U.S. planemaker and rival Airbus that Spirit has not repaid.

Hours after announcing it will receive up to $350 million in advance payments from Boeing, Spirit said it has an updated memorandum of agreement with Airbus stating the European aerospace giant will provide the major supplier with a $107 million non-interest-bearing line of credit.

Spirit AeroSystems said on Tuesday that Boeing will pay a total of up to $350 million in advance payments to the firm, providing the struggling supplier a lifeline as it continues to burn cash after four consecutive years of losses.