Action
Notice of proposed rulemaking (NPRM).
Summary
We propose to supersede Airworthiness Directive (AD) 2006-22- 15, which applies to all Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, 747SR, and 747SP series airplanes. AD 2006-22-15 currently requires repetitive inspections for cracking of certain panel webs and stiffeners of the nose wheel well (NWW), and corrective actions if necessary. AD 2006-22-15 also requires replacing certain panels with new panels, which terminates the repetitive inspections. Since we issued AD 2006-22-15, we received reports of fatigue cracking in the panel webs and stiffeners of the NWW prior to the inspection threshold of AD 2006-22-15. This proposed AD would reduce a compliance time and add certain inspections and repair if necessary. We are proposing this AD to prevent fatigue cracking of the NWW side and top panels, which could result in a NWW depressurization event severe enough to reduce the structural integrity of the fuselage.