Final answer:
The central idea of "A Cub Pilot" revolves around the personal and professional growth of a young pilot, which is illustrated through his experiences and lessons learned.
Step-by-step explanation:
The central idea of "A Cub Pilot" can be identified as the growth and development of a young pilot in a challenging and demanding occupation. This idea is developed through the experiences and interactions the cub pilot has with his environment and colleagues. The author employs various literary devices to depict the protagonist's journey from inexperienced and tentative to capable and confident. An example from the passage that supports this central idea is when the protagonist faces a particularly difficult challenge on the river. The way he handles the situation, reflects on his mistakes, and learns from them provides evidence of his ongoing development. The detailed descriptions and character interactions serve to vividly illustrate the cub pilot's growth. Additionally, the synthesis of evidence and development of ideas within the paragraph provide a clear trajectory of the central theme, inviting the reader to engage with the protagonist's evolving understanding of his role and the lessons learned along the way.