TM 1-1520-253-23
6.4.3.1 NDI Equipment and Materials. Inspection equipment shall be selected from the approved
list in Table 1-7, and AMS-2644 level 3 penetrant materials shall be selected from the approved list
in Table 1-8. Parts requiring fluorescent penetrant inspection shall be cleaned prior to inspection
with n-Propyl Bromide (vapor degreasing only) (Table 1-8), DS-108 (Table 1-8). DS-108, Electron,
Positron must be followed by an Acetone (Table 1-8) or Isopropyl Alcohol (Table 1-8) rinse or wipe;
or drying until there is no visible solvent residue left on parts.
6.4.3.2 Preparation of Helicopter. The helicopter shall be prepared for safe ground maintenance.
Partial inspection for cause (visual indications, sites of mechanical damage, corrosion, etc.) may
be performed on all exposed surfaces of the installed part using this procedure. If required, the
connecting link shall be removed in accordance with the applicable technical manuals listed in
6.4.3.3 Access. Access is obtained through transmission work platforms, flight controls closet
panel, or cockpit, See Figure 1-4 - CH-47: 9, 27, 34, and/or 47: MH-47: 16, 17, and 32.
6.4.3.4 Preparation of Part. Protective coating shall be removed and the part shall be thoroughly
cleaned. Refer to Preparation of Part or Area for NDI, paragraph 1.4.4.
6.4.3.5 Inspection Procedure. Perform fluorescent penetrant inspection. Refer to Fluorescent
Penetrant Method, paragraph 1.4.7 and Table 1-4. Inspect area of concern. See Figure 6-4.
6.4.3.6 Marking and Recording of Inspection Results. Mark and record as required by paragraph
6.4.4 Backup Method. None required.
6.4.5 System Securing. Clean the connecting link to remove inspection media. Refer to Post
Cleaning and Restoration of Part or Area After NDI, paragraph 1.4.16. The connecting link, if
removed, requires installation in accordance with the applicable technical manuals listed in
NDI_CH/MH-47F6_4
6-8
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