Final answer:
A powerplant mechanic can perform certain maintenance tasks on the airframe of an FAA-certificated aircraft, excluding areas directly related to airworthiness. Repairs to the primary structure or any work that affects airworthiness must be done by a certified airframe mechanic.
Step-by-step explanation:
A mechanic with only a powerplant rating can perform maintenance on the airframe of an FAA-certificated aircraft under certain conditions. According to the Federal Aviation Regulations (FARs) Part 65, a powerplant mechanic can perform minor repairs and alterations on the aircraft structure, excluding areas directly associated with the airworthiness of the aircraft. However, any work that affects the airworthiness of the airframe or requires specialized knowledge must be performed by a certified airframe mechanic.
For example, a powerplant mechanic can replace an engine cowling or perform repairs on the landing gear structure, as these areas are not directly related to the airworthiness of the aircraft. But if there is damage to the primary structure of the aircraft, such as a wing spar or fuselage damage, a certified airframe mechanic must handle the repairs.
It's essential to follow the regulations outlined by the FAA to ensure the safety and airworthiness of the aircraft. If in doubt, it's always best to consult with a certified airframe mechanic.