Summary
The FAA proposes to adopt a new airworthiness directive (AD) for certain Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747SR, and 747SP series airplanes. This proposed AD would require repetitive inspections for cracking of the station (STA) 1241 bulkhead fittings just above the canted pressure deck; a one-time determination of the edge margin at seven fastener positions on each side of the airplane; and related investigative/ corrective actions if necessary. This proposed AD results from a report that an operator found a 1.65-inch crack on the STA 1241 bulkhead fitting on the left side of a Boeing Model 747-200F series airplane that had accumulated 17,332 total flight cycles. We are proposing this AD to detect and correct cracking in the STA 1241 bulkhead fittings, which could result in reduced structural integrity of the airplane.