These resource references will help you find alerts from the FAA and manufacturers for safety issues including Airworthiness Directives and Service Bulletins.
FAA Airworthiness Directives
https://www.faa.gov/regulations_policies/airworthiness_directives
Aircraft Manufacturers
American Champion Aircraft: https://www.americanchampionaircraft.com/service-letters
APEX Aircraft (CAP) - CAP Model 10B:
- https://www.tmcnet.com/usubmit/2011/03/09/5364629.htm
- Shaw Letter regarding Service Bulletin number 060307, CAP 10C- Wing - Main Spar - Central Spar Cap 10/6/2006
Aviat Aircraft: https://aviataircraft.com/pitts-service-bulletins/
Extra Aircraft: https://www.extraaircraft.com/techservice.php
Van's Aircraft: https://www.vansaircraft.com/
Other Manufacturers
Butler Parachutes: https://www.butlerparachutes.com
Hartzell Propeller: https://hartzellprop.com/services/technical-support/
Lycoming: http://www.lycoming.com/contact/knowledge-base/publications
MT Propeller: https://www.mt-propeller.com/en/entw/serviced.htm
National Parachute: https://nationalparachute.com
Para-Phernalia Softie Parachutes: http://www.softieparachutes.com/maintenance/
Strong Parachutes: https://strongparachutes.com/Support/Service-Bulletins
Whirlwind Propeller: https://www.whirlwindaviation.com/serviceletters/index.asp