135.53 Aircraft airworthiness

• (a) Each holder of an air operator certificate shall ensure that each aircraft it uses in conducting an air transport operation has a current standard category airworthiness certificate.
• (b) Each holder of an air operator certificate shall ensure that each aircraft it uses in conducting a commercial transport operation has--
  • (1) a current standard category airworthiness certificate; or
  • (2) a current restricted category airworthiness certificate provided that the aircraft flight manual allows such an operation.