TM 1-1520-253-23
COMBUSTION CHAMBER HOUSING (PT).
5.11.1 Description (Figure 5-1, Index No. 11). Induced air is compressed, mixed with fuel, and
ignited in the combustion chamber. There are eight nut plates positioned on the combustion
chamber housing. Method of attachment is tack-welded using inert gas method.
5.11.2 Defects. Inspect to tack welds for cracks. No cracks are allowed.
5.11.3 Primary Method. Fluorescent Penetrant.
5.11.3.1 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.
5.11.3.2 Preparation of Helicopter. The helicopter shall be prepared for safe ground maintenance.
If required, the combustion chamber housing shall be removed in accordance with the applicable
technical manuals listed in Table 1-1.
5.11.3.3 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.
5.11.3.4 Preparation of Part. Refer to Preparation of Part or Area for NDI, paragraph 1.4.4.
5.11.3.5 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 5-11.
5.11.3.6 Marking and Recording of Inspection Results. Mark and record as required by paragraph
5.11.4 Backup Method. None required.
5.11.5 System Securing. Clean the combustion chamber housing to remove inspection media.
Refer to Post Cleaning and Restoration of Part or Area After NDI, paragraph 1.4.16. The combus-
tion chamber housing, if removed, requires installation in accordance with the applicable technical
manuals listed in Table 1-1. Secure the engine upper and lower doors.
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