IO-390-D Series Engine Maintenance Manual
05-50
© 2020 Avco Corporation. All Rights Reserved
Page 64
March 2020
IO-390-D Series Engine Maintenance Manual
2.
Non-Destructive Testing (Magnetic Particle Inspection and Fluorescent Penetrant Inspection)
Refer to the latest revision of Service Instruction No. SI-1285 for additional details.
A.
Non-destructive testing (NDT) that can be done on engine components includes Magnetic
Particle Inspection (MPI) and Fluorescent Penetrant Inspection (FPI). The purpose of the
NDT is to identify the presence or potential of structural failures in an engine component.
The MPI is used for detection of discontinuities on the surface and/or sub-surface of
ferroelectric materials such as iron, nickel, cobalt, and some of their alloys.
The FPI is used to identify casting, forging and welding surface defects such as hairline
cracks, surface porosity, leaks in new products, and fatigue cracks on in-service components.
B.
Penetrant Materials Used for NDT
Do not use visible dye for MPIs or FPIs because visible dye penetrant materials have an
adverse effect on future penetrant inspections which can cause indications to be tightly
closed and therefore missed during future inspections.
C.
Requirements for NDT Personnel
Personnel who complete the Magnetic Particle and Fluorescent Penetrant Inspections on
Lycoming engine components must be qualified and certified to a written procedure in
accordance with
NAS-410, Certification and Qualification of NDT personnel.
Also, personnel
who make the "accept" or "reject" decisions during the inspections must be qualified and
certified to at least Level II in accordance with NAS-410.
D.
NDT Inspection Procedure Requirements and Guidelines
There must be written procedures for the Magnetic Particle Inspection and the Fluorescent
Penetrant Inspection that have been approved by someone who is qualified and certified to
Level III in accordance with NAS-410.
E.
Before NDT, clean the components per the “Cleaning Method for Non-Destructive Testing”
in Chapter 05-30.
F.
Inspection Guidelines
(1)
The inspections must be done per established acceptance criteria to ensure component
conformance.
(2)
A 3 power to 10 power magnifying glass must be used to evaluate indications.
(3)
If a Magnetic Particle Inspection is difficult to do on an odd-shaped part, the Fluorescent
Penetrant Inspection can be used if the acceptance criteria are concerned about surface
indications only.
