Action
Final rule.
Summary
The FAA is superseding an existing airworthiness directive (AD), 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, and 747SR series airplanes. That AD currently requires repetitive inspections to find cracking of the web, strap, inner chords, and inner chord angle of the forward edge frame of the number 5 main entry door cutouts, and repair, if necessary. This new AD requires expanding the inspection areas to include the frame segment between stringers 16 and 23. This AD reinstates the repetitive inspections specified above for certain airplanes. This AD also requires repetitive inspections for cracking of repairs. This AD results from additional reports of cracks that have been found in the strap and inner chord of the forward edge frame of the number 5 main entry door cutouts, between stringers 16 and 23. We are issuing this AD to detect and correct such cracks. This condition, if not corrected, could cause damage to the adjacent body structure, which could result in depressurization of the airplane in flight.