Airworthiness Directives; The Boeing Company Airplanes

We are adopting a new airworthiness directive (AD) for The Boeing Company Model 707 airplanes equipped with a main cargo door (MCD). This AD was prompted by analysis of the cam support assemblies of the MCD that indicated the repetitive high frequency eddy current (HFEC) inspections required by the existing maintenance program are not adequate to detect cracks before two adjacent cam support assemblies of the MCD could fail. This AD requires repetitive ultrasonic inspections for cracking of the cam support assemblies of the MCD, and replacement if necessary. We are issuing this AD to address the unsafe condition on these products.