Summary
We propose to adopt a new airworthiness directive (AD) for all The Boeing Company Model 767-200, -300, and -300F series airplanes. This proposed AD was prompted by a finding that certain barrel nuts installed at the vertical fin may be subject to stress corrosion and cracking. This proposed AD would require either repetitive inspections of vertical fin barrel nuts for corrosion or a magnetic check to identify certain barrel nuts, and corrective actions if necessary. We are proposing this AD to detect and correct corroded and loose barrel nuts that attach the vertical fin to body section 48, which could result in reduced structural integrity of the vertical fin attachment joint, loss of the vertical fin, and consequent loss of controllability of the airplane.