Summary
We propose to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 787-8 and 787-9 airplanes equipped with General Electric engines. This proposed AD was prompted by reports of cracking in barrel nuts on a forward engine mount of Model 747-8 airplanes, which shares a similar design to the forward engine mount of Model 787-8 and 787-9 airplanes. This proposed AD would require, for certain airplanes, replacement of the four barrel nuts of the forward engine mount on each engine. For certain other airplanes, this proposed AD would require an inspection to determine if any forward engine mount barrel nut having a certain part number is installed, and related investigative and corrective actions if necessary. We are proposing this AD to detect and correct cracking of the forward engine mount barrel nuts; such cracking could result in reduced load capacity of the forward engine mount and could result in separation of an engine from the airplane, and consequent loss of control of the airplane.