Summary
The FAA proposes to adopt a new airworthiness directive (AD) for certain Boeing airplanes listed above. This proposed AD would require repetitive detailed inspections of the midspar web of the inboard and/or outboard struts for cracking, disbonding, or buckling; repetitive detailed inspections of the midspar stiffeners for any crack or fracture; related investigative actions; and corrective actions, if necessary. This proposed AD is prompted by reports of cracking in the midspar web. We are proposing this AD to detect and correct cracking in the midspar assembly, which could result in the loss of the midspar assembly load path, and could, combined with the loss of the Nacelle Station 180 bulkhead load path, lead to the separation of the engine from the airplane.