MAIN ROTOR BLADE (VOIDS) (BT).
Description (Figure 2-1. Index No. 4). The main rotor blade assemblies are rotating airfoils with swept tips that
are constructed of stainless steel and fiberglass. Each attaches to the main rotor head assembly by a lead lag link and a
blade attachment pin.
Defects. Void damage can occur anywhere on both sides of the blade shown in Figure 2-4.
A void is defined as an unbonded area that is supposed to be bonded. Many subdefinitions are given,
such as lack of adhesive, gas pocket, misfit, etc. However, this manual makes no distinction among
these, instead grouping them all under one general term ("void").
Primary Method. Bond Testing.
220.127.116.11 NDI Equipment and Materials. (Refer to Appendix B.)
Bond Test Unit
Probe, Mechanical Impedance Analysis
Test Block, metal honeycomb with skin thickness closest to that of the panel to be inspected
Test Block, Composite Defect Standard #1
Teflon Tape, refer to Table 1-8
Aircraft Marking Pencil, refer to Table 1-8
18.104.22.168 Preparation of Helicopter. The helicopter shall be prepared for safe ground maintenance in accordance with the
applicable technical manuals listed in Table 1-1.
22.214.171.124 Access. Not applicable.
Use only appropriate platforms, workstands, or other approved locally procured stands
and restraint equipment when working above 10 feet on helicopter in a nontactical
environment. Otherwise, personnel injury could result from accidental falls.
126.96.36.199 Preparation of Part. The main rotor blades shall be thoroughly cleaned. Refer to Preparation of Part or Area for
NDI, paragraph 1.4.4.