Which of the following describes landing gear configurations?

Landing gear configurations are crucial to understanding aircraft design and functionality. The correct choice, which refers to fixed and retractable configurations, identifies the two primary types of landing gear systems found in aircraft.

Fixed landing gear is a design where the gear remains in a permanent position during flight and landing. This configuration is simple and lightweight, making it suitable for many smaller or slower aircraft. The advantage of fixed gear is its reliability and lower maintenance, although it can increase aerodynamic drag.

Retractable landing gear, on the other hand, can be raised into the aircraft structure during flight to reduce drag and improve aerodynamic efficiency. This system is commonly used in faster and larger aircraft where performance is critical. It allows for streamlined profiles, resulting in smoother flight characteristics and better fuel efficiency.

In summary, the classification of landing gear as fixed and retractable illustrates the primary distinctions in design intended to meet specific operational needs and performance enhancements of various aircraft types.