WASHINGTON (Reuters) -Shares of Spirit AeroSystems dropped 16% in extended trade after the company announced new measures meant to raise capital for the embattled aerospace supplier.

The company announced a proposed public sale of $200 million of its Class A common stock. It also plans to issue $200 million in convertible debt set to mature in 2028.

Its shares, which closed flat at $24.62, fell to $20.68 in after-hours trading.

Spirit - which produces large aircraft structures like wings and fuselages for Boeing and Airbus - has struggled with production quality problems that have slowed aircraft deliveries. Inflationary pressures, supply chain constraints and a hike in labor costs have also contributed to a $692 million net loss over the first nine months of 2023.

Its shares have fallen almost 20% since the beginning of the year, but showed some recovery after the October announcement of a new agreement with Boeing aimed at boosting Spirit's near-term revenue by increasing the price the U.S. planemaker pays for 787 Dreamliner components.

During an earnings call with investors last week, Spirit CEO Patrick Shanahan, who became its interim chief executive in October, said reaching a similar pricing agreement with Airbus is an "item of utmost urgency."

Chief Financial Officer Mark Suchinski said then that the company "continue(s) to evaluate all refinancing options to address debt," including $1.2 billion of debt set to mature in 2025, "as well as our overall liquidity."

(Reporting by Valerie Insinna; Editing by Chris Reese and Stephen Coates)