Airworthiness Directives
Twisted-Wrench LLC  Aircraft Maintenance Special Projects
Part 39 of the Federal Aviation Regulations (Title 14, Aeronautics and
Space, of the Code of Federal Regulations) is the regulatory authority
Airworthiness Directives.

39.3   Definition of airworthiness directives (ADs).
FAA's airworthiness directives are legally enforceable rules that apply to the
following products: aircraft, aircraft engines, propellers, and appliances.
All Airworthiness Directives require some action, on some product, at some time.

  • Maintenance
  • Alterations
  • Inspections

  • The Product may be
  • An Aircraft
  • An Aircraft Engine
  • A Propeller
  • An Appliance

  • The Time may be
  • Measured by Calendar Time, Aircraft, Engine, Prop, or Appliance Total
    Time or Time Since Overhaul, or Aircraft Total Landings, or Engine, Prop,
    or Appliance Total Cycles
  • Compliance requirement may be immediate or some time in the future
AD compliance is a FAA Hot Button issue that is taken very seriously.
Highlights from AC 39-7D


The owner or operator of an aircraft is primarily responsible for maintaining
that aircraft in an Airworthy condition, including compliance with ADs.

Required Entries into Records.

The person accomplishing the AD is required by 43.9 to record AD through
(a)(4). The
owner or operator is required by 91.405 to ensure that
maintenance personnel make appropriate entries and, by 91.417, to maintain
those records.
Owners and operators should note that there is a difference
between the records required to be kept by the owner under 91.417 and
those that 43.9 requires maintenance personnel to make. In either case, the
owner or operator is responsible for maintaining proper records.
AC No: 39-7D   Airworthiness Directives

This advisory circular (AC) provides guidance
and information to
owners and operators of
concerning their responsibility for
complying with Airworthiness Directives (AD)
and recording AD compliance in the
appropriate maintenance records.
Renter or Borrower - You are the
operator and have all this
responsibility but sadly,
no management authority.
How do I find all the Airworthiness Directives that apply to my
aircraft, engine, prop, and appliances?
- and -
How do I verify that they have been accomplished as required?

Click Here for Step by Step Instructions.