The Federal Aviation Administration (FAA) recently adopted an airworthiness directive requiring initial and repetitive inspections of CFM56-7B engine fan blades on the concave and convex sides of the fan blade dovetail.
The directive aligns the FAA with the European Aviation Safety Agency rules and will go into effect on May 14.
The inspections’ purpose is to detect cracked fan blades and replace damaged blades. Inspections must be performed within 113 days of the effective date or before the blade accumulates 20,000 cycles.
“The FAA has found that the risk to the flying public justifies waiving notice and comment prior to the adoption of this rule because certain fan blades must be inspected, and, if needed, replaced before further flight,” the agency said.
The directive was issued in response to the in-flight blade failure of Southwest Airlines Flight 1380 in April. During the incident, the jet’s left wing broke mid-flight and the aircraft banked more than 40 degrees before being leveled. A window was broken by debris and passenger Jennifer Riordan was partially sucked out the window. She later died at the hospital. Seven other people were injured in the accident.
An emergency directive was issued immediately following the disaster requiring a one-time ultrasonic inspection. That directive applied to blades with 30,000 or more accumulated flight cycles.