Summary
The FAA proposes to adopt a new airworthiness directive (AD) for all Boeing Model 727 airplanes. This proposed AD would require repetitive external high frequency eddy current (HFEC) inspections of the crown skin for cracks at certain stringer attachment holes, and repair if necessary. This proposed AD results from a report of cracks at multiple locations on certain areas of the crown skin. We are proposing this AD to detect and correct fatigue cracks of the crown skin, which could result in rapid decompression of the airplane.