Plane Sense 8 8-2 issued without adhering to the applicable consensus  standard.”  These records may be discarded when the work is  repeated or superseded by other work, or 1 year after  the work is performed. m  CAUTION: Keep in mind that as a result of  repairs or alterations, such as replacing radios and  installing speed kits, it may be necessary to amend  the weight and balance report, equipment list, flight manual, etc. Light-sport category aircraft certificated pursuant  to 14 CFR part 21, section 21.190 have mandatory  compliance with all manufacturer safety directives.  A service bulletin contains a recommendation from  the manufacturer, with which that manufacturer  believes the aircraft owner should comply, that often  reflects a safety-of-flight issue that the manufacturer  believes should be addressed within a certain time- frame. It may result from an improvement developed  by the manufacturer, or it may address a defect in a product or published documentation. Most maintenance performed on an aircraft is recor- ded in the aircraft logbooks. As an aircraft owner, it  is important to ensure that your aircraft’s logbooks  are complete and up to date at all times. The aircraft  logbooks outline the maintenance history of your air-  craft, and any prospective buyer will want to review  the aircraft and all maintenance performed. In addi- tion, any A&P or certificated repair station performing maintenance on your aircraft will want to review the prior maintenance performed on the aircraft. The manufacturer responds to one of these situa- tions by issuing a service bulletin that recommends  a certain type of inspection, replacing certain  components, performing maintenance in a specific  manner, or limiting operations under specified  conditions. Sometimes, compliance with a service  bulletin may be triggered by the occurrence of a particular event (e.g., the lapse of time or operation  under certain types of conditions). An aircraft owner is required to comply with all  applicable ADs issued by the FAA for his or her  aircraft. The FAA issues ADs to notify aircraft owners  and other interested persons of unsafe conditions  and to specify the corrective action required,  including conditions under which the aircraft may  continue to be operated.  The aircraft’s maintenance records should indicate  the current status of all applicable ADs, including for  each: A mechanic who performs a major repair or major  alteration shall record the work on FAA Form 337  and have the work inspected and approved by a mechanic who holds an inspection authorization (IA). (Light-sport aircraft do not require Form 337 when  altering a non-approved product.) A signed copy  shall be given to the owner and another copy sent  to the FAA Aircraft Registration Branch (AFS-750)  in Oklahoma City, Oklahoma within 48 hours of  aircraft approval for return to service. However,  when a major repair is done by a certificated repair  station, the customer’s work order may be used  and a release given as outlined in 14 CFR Part 43,  Appendix B, Recording of Major Repairs and Major  Alterations. You can obtain additional information  and instructions for completing FAA Form 337 in  Advisory Circular (AC) 43-9 (as revised), Aircraft  Maintenance Records.  Figure 8-2  at the end of this  chapter is a sample FAA Form 337. Each time maintenance, including preventive main-  tenance, is performed on your aircraft, an appropriate  entry must be added to the maintenance records. The owner or operator of an aircraft having a  special airworthiness certificate must comply with  each safety directive applicable to the aircraft that  corrects an existing unsafe condition or corrects  the condition in a manner different from safety  directive specifications if the person issuing the  directive agrees with the action. Otherwise, the  owner or operator may, in accordance with 14 CFR  part 91, section 91.327, “obtain an FAA waiver from  the provisions of the safety directive based on a  conclusion that the safety directive was  entries into Aircraft maintenance records safety directives FAA Form 337, major repair and Alteration Airworthiness directives logbooks service Bulletins • AD number, • Method of compliance, • Revision date, and • Recurring action (if applicable) including the  time  and date of the next action required.