About Airworthiness Directives

1. Definitions

  • AD Schedule is the primary document for promulgating ADs and contains the individual ADs, as at the date of issue, applicable to the aircraft, engine, or equipment to which the schedule applies.
  • Daily means on any day the affected aircraft, engine, or component is operated.
  • Effective Date is the date from which compliance must be established.
  • Emergency AD means an AD which requires urgent compliance, and is notified directly to the registered owners of affected aircraft.
  • FAA AD means an AD issued by the Federal Aviation Administration of the USA.
  • LBA AD means an AD issued by Luftfahrt-Bundesamt of Germany.
  • SB, SL, SIN, TNS means Service Bulletin, Service Letter, Service Information Notice, and Technical News Sheet respectively, issued by the manufacturer of the particular aircraft, engine, or component.
  • S/N, P/N means Serial Number, and Part Number respectively.
  • Through used in relation to serial numbers, means inclusive of the serial numbers quoted and all numbers between.
  • TIS, TTIS means time in service, and total time in service respectively.

2. Promulgation

ADs are normally promulgated in AD Schedules. Each AD is presented under the following headings -

AD code: The basic reference number that must be used when making relevant entries in log books and maintenance records.
Applicability: The aircraft or component to which the AD applies.
Requirement: Specifies a document, such as a manufacturer's SB, which forms part of the requirement and which contains all the information necessary for implementation. An AD may vary information given in a manufacturer's SB or other reference document and is overriding.
Compliance: States, usually by date or period of time in service, when an AD shall have been complied with; also, where applicable, the maximum periods between repetitive inspections. Unless otherwise stated, the interval between repetitive inspections required by an AD may be adjusted by up to 10 per cent of the specified interval to allow accomplishment concurrently with other scheduled maintenance of aircraft components or equipment affected.
Effective date: Is the date from which compliance must be established.