TM 1-1520-253-23
3.20.3.2
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 oil cooler shall be removed and disassembled in accordance with
the applicable technical manuals listed in Table 1-1.
3.20.3.3
Access. Access is through the forward and aft transmission work platform and combiner transmission doors.
See Figure 1-4 - CH-47: 9, 23, 27, and/or 34; MH-47: 16, 17, and 30.
3.20.3.4
Preparation of Part. Protective coating shall be removed only from the area of interest and the part shall be
thoroughly cleaned. Refer to Preparation of Part or Area for NDI, paragraph 1.4.4.
3.20.3.5
Inspection Procedure. Perform fluorescent penetrant inspection. Refer to Fluorescent Penetrant Method,
3.20.3.6
Marking and Recording of Inspection Results. Mark and record as required by paragraph 1.3.
3.20.4 Backup Method. None required.
3.20.5 System Securing. Clean the part or area to remove inspection media. Refer to Post Cleaning and Restoration of
Part or Area After NDI paragraph 1.4.16. Protective coating shall be reapplied as required. Reinstall or assemble parts
or components in accordance with the applicable technical manuals listed in Table 1-1. Secure the transmission work
platforms, combiner transmission, and doors that were used.
