Category Archives: Liquid Penetrant

FAA CE-18-26 Propeller failure

 A recent accident involving an in-flight propeller failure and separation has again brought to light the need for continued diligence in the use of liquid penetrant inspection methods. These methods involve the use of Type I fluorescent penetrants (visible under ultraviolet light) and Type II visible penetrant (visible under ordinary white light), (Ref. Aerospace Material Specification (AMS) 2644 Inspection Material, Penetrant). During the examination of the failed propeller, there were remnants of visible dye penetrant (red dye) material found in the bolt holes, which may have affected subsequent inspections. 

At this time, the airworthiness concern is not an unsafe condition that would warrant any additional airworthiness directive (AD) action under Title 14 of the Code of Federal Regulations (14 CFR) part 39.