Certificated pilots, excluding student pilots, sport pilots, and  recreational pilots, may perform preventive maintenance on  any aircraft that is owned or operated by them provided that  the aircraft is not used in air carrier service and does not  qualify under 14 CFR parts 121, 129, or 135. A pilot holding  a sport pilot certificate may perform preventive maintenance  on an aircraft owned or operated by that pilot if that aircraft is  issued a special airworthiness certificate in the LSA category.  (Sport pilots operating LSA should refer to 14 CFR part 65  for maintenance privileges.) 14 CFR part 43, appendix A,  contains a list of the operations that are considered to be  preventive maintenance.  Repairs and alterations are classified as either major or minor.  14 CFR part 43, appendix A, describes the alterations and  repairs considered major. Major repairs or alterations shall  be approved for return to service on FAA Form 337, Major  Repair and Alteration, by an appropriately rated certificated  repair station, an FAA-certificated A&P mechanic holding an  IA, or a representative of the Administrator. Minor repairs and  minor alterations may be approved for return to service with a  proper entry in the maintenance records by an FAA-certificated  A&P mechanic or an appropriately certificated repair station.  For modifications of experimental aircraft, refer to the  operating limitations issued to that aircraft. Modifications  in accordance with FAA Order 8130.2, Airworthiness  Certification of Aircraft and Related Products, may require  the notification of the issuing authority.  A special flight permit is a Special Airworthiness Certificate  authorizing operation of an aircraft that does not currently  meet applicable airworthiness requirements but is safe  for a specific flight. Before the permit is issued, an FAA  inspector may personally inspect the aircraft or require it to  be inspected by an FAA-certificated A&P mechanic or an  appropriately certificated repair station to determine its safety  for the intended flight. The inspection shall be recorded in  the aircraft records.  The special flight permit is issued to allow the aircraft to be  flown to a base where repairs, alterations, or maintenance  can be performed; for delivering or exporting the aircraft; or  for evacuating an aircraft from an area of impending danger.  A special flight permit may be issued to allow the operation  of an overweight aircraft for flight beyond its normal range  over water or land areas where adequate landing facilities  or fuel is not available.  If a special flight permit is needed, assistance and the  necessary forms may be obtained from the local FSDO  All ADs and the AD Biweekly are free on the Internet  at http://rgl.faa.gov and are available through e-mail.  Individuals can enroll for the e-mail service at the website  above. Paper copies of the Summary of Airworthiness  Directives and the AD Biweekly may be purchased from  the Superintendent of Documents. The Summary contains  all the valid ADs previously published and is divided into  14 CFR, part 91, section 91.417 requires a record to be  maintained that shows the current status of applicable  ADs, including the method of compliance; the AD number  and revision date, if recurring; next due date and time; the  signature; type of certificate; and 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 ADs in the back of their aircraft, engine, and  propeller maintenance records.  ADs are regulatory and shall be complied with unless a  specific exemption is granted. It is the responsibility of the  aircraft owner or operator to ensure compliance with all  pertinent ADs, including those ADs 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 determine if an AD applies to an  amateur-built aircraft, contact the local FSDO.  or Designated Airworthiness Representative (DAR).  [Figure 9-10]  A primary safety function of the FAA is to require correction  of unsafe conditions found in an aircraft, aircraft engine,  propeller, or appliance when such conditions exist and are  likely to exist or develop in other products of the same design.  The unsafe condition may exist because of a design defect,  maintenance, or other causes. Airworthiness Directives  (ADs), under 14 CFR, part 39, define the authority and  responsibility of the Administrator for requiring the necessary  corrective action. ADs 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. ADs are divided into two categories:  Airworthiness Directives (ADs)  Repairs and Alterations  Special Flight Permits  1. Those of an emergency nature requiring immediate  compliance prior to further flight  2. Those of a less urgent nature requiring compliance  within a specified period of time  9-12 