Summary
We propose to adopt a new airworthiness directive (AD) for certain Model 777-200LR and -300ER series airplanes. This proposed AD would require doing a high frequency eddy current inspection for cracking of the keyway of the fuel tank access door cutout on the left and right wings between wing rib numbers 8 (wing station 387) and 9 (wing station 414.5), and related investigative and corrective actions if necessary. This proposed AD results from reports of cracks emanating from the keyway of the fuel tank access door cutout of the lower wing skin between wing rib numbers 8 and 9. We are proposing this AD to prevent loss of the lower wing skin load path, which could cause catastrophic structural failure of the wing.