An FAA airworthiness directive that will take effect on March 1 mandates that Boeing 767-300 series aircraft operators check for cracks in the fuselage skin and backup structure at the lower very high frequency antenna cutout at station 1196 +99, between stringers 39L and 39R.
You can read the full text of the AD here.
The agency expects the AD to impact 93 U.S. registered airplanes, and it estimates labor costs associated with the mandate to come to $255 per airplane.
FAA says reports of such cracking prompted the AD, which follows a Boeing Special Attention Service Bulletin (767-53-020) from Dec. 17, 2009.
If a crack is found, operators should repair it according to the SB; if not, the inspections should be repeated at intervals not exceeding 3,000 flight cycles.