Regulacje i polityka gospodarcza · 23.09.2008

Airworthiness Directives; Boeing Model 747 Airplanes

The FAA proposes to supersede an existing airworthiness directive (AD) that applies to certain Boeing Model 747 airplanes. The existing AD currently requires repetitive inspections of the body station (BS) 2598 bulkhead, and corrective actions if necessary. The existing AD also currently requires a terminating modification for the repetitive inspections and a post-modification inspection of the modified area. This proposed AD would continue requiring those actions with revised service information. For certain airplanes, this proposed AD would require new repetitive inspections, an interim modification, and post-interim modification inspections. For certain airplanes, this proposed AD also would require replacing any previously repaired aft inner chord and reinstalling the terminating modification. This proposed AD results from reports of cracked aft inner chords on airplanes after certain requirements of the existing AD were done. We are proposing this AD to prevent fatigue cracking of the BS 2598 bulkhead structure, which could result in inability of the structure to carry horizontal stabilizer flight loads, and loss of controllability of the airplane.