aircraft wing spars
Recently read about spar cap corrosion in a PA28 and was wondering a few things about light aircraft wings.
1)HOW ARE THEY SECURED TO THE FUSELAGE
2)WHAT FATIGUE LIFE WOULD A SPAR ON,SAY,A PA28 HAVE
3)IS THERE A PUBLISHED NO OF HOURS AND LANDINGS BEFORE SPAR REPLACEMENT?
If anyone knows it would help satisfy my curiosity.