Which term describes the alteration of an aircraft to conform with an approved standard?

The term that describes the alteration of an aircraft to conform with an approved standard is "modification." In aviation, modification refers specifically to changes made to an aircraft that enhance or alter its performance, safety, or capabilities to ensure compliance with established standards and regulations. This could include structural changes, installation of new systems, or adjustments to existing equipment.

Modifications are typically subject to rigorous review and approval by regulatory bodies to ensure that they meet necessary safety and performance standards. This regulatory oversight helps maintain the integrity of the aircraft and ensures ongoing compliance with industry standards.

Other choices such as overhaul, repair, and maintenance serve different purposes in the context of aircraft. Overhaul usually refers to a comprehensive refurbishment of an aircraft or its components to bring them back to a like-new condition, often involving significant labor and inspection. Repair indicates the act of restoring something that is damaged or malfunctioning to a standard condition but does not necessarily involve changes to compliance standards. Maintenance encompasses routine checks and upkeep to ensure safety and functionality but does not inherently involve alterations to the aircraft's design or capacity. Thus, modification is the correct term in this context for defining changes made to align an aircraft with approved standards.