Summary
The FAA proposes to adopt a new airworthiness directive (AD) for all Boeing Model 707-300B, -300C, and -400 series airplanes. This proposed AD would require repetitive inspections to detect cracked or broken hinge fitting assemblies of the inboard leading edge slats, and corrective action if necessary. This proposed AD would provide as an option a preventive modification, which would defer the repetitive inspections. This proposed AD also would provide an option of replacing all hinge fitting assemblies with new, improved parts, which would terminate the repetitive inspection requirements. This proposed AD is prompted by results of a review to identify and implement procedures to ensure the continued structural airworthiness of aging transport category airplanes. We are proposing this AD to detect and correct fatigue cracking of the hinge fitting assembly of the inboard leading edge slats, which could result in reduced structural integrity of the slat system. This condition could result in loss of the inboard leading edge slat and could cause the flightcrew to lose control of the airplane.