Plane Sense Chapter 8. Airworthiness Directives

A primary safety function of the FAA is to require correction of unsafe conditions found in an aircraft, aircraft engine, propeller, rotor, or appliance when such conditions exist or are likely to exist or develop in other products of the same design. The unsafe conditions can exist because of a design defect, maintenance. or other causes. 14 CFR part 39, Airworthiness Directives (AD’s), defines the authority and responsibility of the FAA Administrator for requiring the necessary corrective action. AD’s are used to notify aircraft owners and other interested persons of unsafe conditions and to specify the conditions under which the product may continue to be operated.

AD’s may be divided into two categories:

1. Those of an emergency nature requiring immediate compliance before further flight, and
2. Those of a less urgent nature requiring compliance within a relatively longer period of time.

AD’s are the “final rule” and shall be complied with unless specific exemption is granted. It is the aircraft owner’s or operator’s responsibility to ensure compliance with all pertinent AD’s. This includes those AD’s that require recurrent or continuing action. For example, an AD may require a repetitive inspection each 50 hours of operation, meaning the particular inspection shall be accomplished and recorded every 50 hours of time in service. Owners/operators are reminded that there is no provision to overfly the maximum hour requirement of an AD unless it is specifically written into the AD. To help you determine if an AD applies to an amateur-built aircraft, contact your local FSDO.

14 CFR section 91.417 requires a record to be maintained that shows the current status of applicable AD’s, including the method of compliance, the AD number and revision date, if recurring, the time and date when due again, the certified mechanic’s signature, the kind of certificate, and the certificate number of the repair station or mechanic who performed the work. For ready reference, many aircraft owners have a chronological listing of the pertinent AD’s in the back of their aircraft and engine records. [Figure 11 ]

The Summary of Airworthiness Directives contains all the valid AD’s previously published. The AD’s are divided into two categories: (1) Small Aircraft under 12,500 pound maximum certificated takeoff weight and Rotorcraft; and (2) Large Aircraft over 12,500 pounds. Both categories have three sets of books plus biweekly supplements. Each book may be purchased separately in paper format or by subscription on paper or microfiche with biweekly supplements. Also all AD’s-Small and Large Aircraft-may be purchased on CD-ROM with updates free on the Internet site

AC 39-7, Airworthiness Directives, provides additional guidance and information for owners and operators of their responsibilities for complying with and recording AD’s.

For more information contact:

Airworthiness Programs Branch, AFS-610
PO. Box 26460
Oklahoma City, OK 73125
Telephone (405) 954-4103
Fax (405) 954-4104