TM 1-1520-253-23
FUEL DRAIN VALVE (PT).
5.10.1 Description (Figure 5-1, Index No. 10). The fuel drain valve is being used here as an
example of inspecting parts while attached to the engine. Any unpainted part that is accessible can
be inspected using this method with little preparation and with little or no disassembly.
5.10.2 Defects. Inspect to verify cracks found visually. No cracks allowed.
5.10.3 Primary Method. Fluorescent Penetrant.
5.10.3.1 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.
5.10.3.2 Preparation of Helicopter. The helicopter shall be prepared for safe ground maintenance.
If required, the fuel drain valve shall be removed in accordance with the applicable technical
manuals listed in Table 1-1.
5.10.3.3 Access. Access is through the engine upper and lower doors from the engine work
platform. See Figure 1-4 - CH-47: 20, 21, and 22: MH-47: 18, 20, and 21.
5.10.3.4 Preparation of Part. Refer to Preparation of Part for Area for NDI, paragraph 1.4.4.
5.10.3.5 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 5-10.
5.10.3.6 Marking and Recording of Inspection Results. Mark and record as required by paragraph
5.10.4 Backup Method. None required.
5.10.5 System Securing. Clean the part to remove inspection media. Refer to Post Cleaning and
Restoration of Part or Area After NDI, paragraph 1.4.16. The fuel drain valve, if removed, requires
installation in accordance with the applicable technical manuals listed in Table 1-1. Secure the
engine upper and lower doors.
Change 1
