On April 20, three days after a Southwest Airlines Boeing 737-700 experienced an engine failure due to a fractured fan blade, resulting in the death of a passenger, the U.S. Federal Aviation Administration issued an emergency airworthiness directive that requires operators of CFM56-7B engines with more than 30,000 flight cycles to perform a one-time ultrasonic inspection of all 24 fan blades to detect cracking.
Magnetic particle inspection is widely used to inspect production parts, parts in service and for periodic inspection of structures such as bridges, aircraft engines and landing gear.
As a quality manager, it’s your worst nightmare. One of your best customers comes for a visit and brings a box of cracked parts that came from your plant. He wants to know how it happened, and how you are going to ensure it won’t happen again.
Magnetic particle inspection (MPI) can be performed a number of different ways and oftentimes any of these methods are acceptable under the specification called out for performing the test.
Since its origin in the late 19th century when a magnetic compass was used to detect defects in magnetized cannon barrels, the selection of the right magnetic particle inspection system could be challenging.
If necessity is the mother of invention, then nondestructive testing (NDT) would be among her favorite progeny, at least with the design engineers and manufacturing sect.