The US Federal Aviation Administration (FAA) is implementing rules requiring additional inspections of fan blades in CFM56-7B engines following the failure incident on Southwest Airlines Flight 1380 last month in Pennsylvania that resulted in a passenger fatality.
The new rules follow the first emergency directive issued by the FAA and European regulators last month that required the ultrasonic inspection of nearly 700 CFM56-7B engines worldwide within 20 days on Boeing 737 Next Generation airplanes. Those initial inspections were on fan blades used in more than 30,000 cycles.
The FAA now specifies that another group of the engines will need to be inspected by August under the regulation. It is also requiring repeat inspections of engines. The FAA said an “unsafe condition exists that requires the immediate adoption” of the rule without a chance for public comment, in a notice posted in the US federal register.
CFM International, jointly owned by GE Aviation and Safran Aircraft Engines, said in a statement that the FAA’s latest Airworthiness Directive requires inspections by August of CFM engines with 20,000 cycles of use. Also, that it requires regular inspections for fan blades every additional 3,000 cycles, or about every two years.
“This new Airworthiness Directive mandates ultrasonic and eddy current inspection of all CFM56-7B fan blades that have accumulated more than 20,000 cycles as outlined in the CFM Service Bulletin issued on April 20th. These inspections are to be completed by August 31, 2018,” it stated. “The AD also mandates that airlines continue to perform these inspections every 3,000 cycles (1.5 to 2 years of operation). In addition, airlines are required to perform these inspections on fan blades once they reach the 20,000-cycle threshold, with the continued 3,000-cycle inspections.”
This latest action, said CFM, mirrored its own service bulletin and the EASA Airworthiness Directive issued on 20 April, which recommended ultrasonic inspections on all the engines with 30,000 cycles, as well as similar inspections by the end of August on those with 20,000 cycles. It also recommended inspections of all other fan blades when they reach 20,000 cycles.
The inspections, which can be conducted on-wing with an ultrasonic probe along the surface of the fan blade, takes about four hours per engine.
