The Federal Aviation Administration has issued a new airworthiness directive (AD) for Boeing 777 aircraft to address potential wing cracking issues. The directive, which goes into effect on April 23, applies to all Boeing 777-200, -200LR, -300, -300ER, and 777F series airplanes.
This AD was prompted by the discovery of a 5-inch crack on the upper wing skin of a 777’s right wing. The agency noted that undetected upper wing skin cracks could compromise the airplane’s structural integrity, potentially leading to loss of control.
To address this issue, the AD requires airlines to conduct repetitive inspections of the upper wing skin near certain fasteners. Specifically, it mandates open-hole high-frequency eddy current inspections instead of the ultrasonic inspections originally proposed.
This change came after Boeing reported two instances where cracks were initiated in some fasteners, which were only detected due to repairs on adjacent fasteners.
Airlines must follow the procedures outlined in a July 2023 bulletin from Boeing to carry out the inspections. The FAA estimates that complying with this AD will cost U.S. operators approximately $1,576,240 per inspection cycle, based on a fleet of 323 affected aircraft.
If cracks are found during inspections, operators must repair them before further flight using FAA-approved methods.
The FAA emphasized that the AD is necessary to prevent a situation in which the wing structure could fail to sustain required loads, which could lead to loss of control of the airplane.
While some carriers – including United and American – requested extended compliance times or limitations on which aircraft require inspection, the FAA maintained its position on the urgency and scope of the directive based on fleetwide crack report data.
