Summary
The FAA proposes to supersede Airworthiness Directive (AD) 2016-07-28, which applies to all The Boeing Company Model DC-9-81 (MD- 81), DC-9-82 (MD-82), DC-9-83 (MD-83), and DC-9-87 (MD-87) airplanes, and Model MD-88 airplanes. AD 2016-07-28 requires repetitive eddy current high frequency (ETHF) inspections for any cracking in the left and right side center wing lower skin, and repair if any crack is found. Since the FAA issued AD 2016-07-28, the FAA has determined it is necessary to expand the inspection area to include adjacent stringers with similar stress levels and to perform an inspection with increased sensitivity for crack detection. This proposed AD would retain certain requirements of AD 2016-07-28, expand the inspection area, and require new inspections. The FAA is proposing this AD to address the unsafe condition on these products.