The ratings of 3 Aerospace & Defense stocks are down this week, according to the Portfolio Grader database. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

Moog Inc. Class A (MOG.A) earns a D this week, moving down from last week’s grade of C. Moog Inc. Class A manufactures precision motion control components and systems. For more information, get Portfolio Grader’s complete analysis of MOG.A stock.

Cubic Corporation (CUB) experiences a ratings drop this week, going from last week’s C to a D. Cubic Corporation designs, develops, manufactures, and installs products that are primarily electronic in nature, such as equipment used in customized military range instrumentation, training and applications systems, and automated revenue collection systems. The company also gets F’s in earnings revisions and earnings surprise. For more information, get Portfolio Grader’s complete analysis of CUB stock.

This week, Ducommun Incorporated’s (DCO) rating worsens to a D from the company’s C rating a week ago. Ducommun Incorporated designs, engineers and manufactures aerostructure and electromechanical components and subassemblies, and provides engineering, technical and program management services mainly for the aerospace industry. The company also gets F’s in sales growth, operating margin growth, and free cash flow. For more information, get Portfolio Grader’s complete analysis of DCO stock.

Louis Navellier’s proprietary Portfolio Grader stock ranking system assesses roughly 5,000 companies every week based on a number of fundamental and quantitative measures. Stocks are given a letter grade based on their results — with A being “strong buy,” and F being “strong sell.” Explore the tool here.