Summary
The FAA proposes to adopt a new airworthiness directive (AD) for certain Boeing Model 747-200B, 747-200C, 747-200F, 747-300, 747- 400, and 747SP series airplanes. This proposed AD would require doing a detailed inspection of the left and right longeron extension fittings, and corrective action if necessary. This proposed AD results from cracking found in the longeron extension fitting at body station 1480 due to accidental damage during production. We are proposing this AD to detect and correct cracking in the longeron extension fitting, which could result in rapid decompression of the airplane and possible in- flight breakup of the airplane fuselage.