Backup Method. None required.
System Securing. Clean the main rotor hub lower plate thoroughly to remove all residual magnetic particle
media. Refer to Post Cleaning and Restoration of Part or Area After NDI, paragraph 1.4.16. The main rotor hub lower
plate requires installation in accordance with the applicable technical manuals listed in Table 1-1.
TAIL ROTOR FORK ASSEMBLY (HEAD AND TEETER STOP) (ET).
Description (Figure 2-1. Index No. 24). The tail rotor fork (head and teeter stop) assembly is a two-armed,
teetering assembly that provides attachment points for the four tail rotor blade assemblies.
Defects. This inspection is used to verify crack indications found visually on the tail rotor fork assembly (head
and teeter stop). No cracks are allowed.
Primary Method. Eddy Current.
Equipment and Materials. (Refer to Appendix B.)
Eddy Current Inspection Unit
Probe, straight, shielded surface, 100 KHz-500 KHz
Probe, right angle, shielded surface, 100 KHz-500 KHz,90 °
1/2 inch drop
Reference Block, three-notched titanium (0.008, 0.020, and 0.040 EDM notches)
Teflon Tape, refer to Table 1-8
Aircraft Marking Pencil, refer to Table 1-8
Preparation of Helicopter. The helicopter shall be prepared for safe ground maintenance. A 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 tail rotor fork assembly (head and teeter stop) shall be removed in
accordance with the applicable technical manuals listed in Table 1-1.
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
Preparation of Part. The part shall be thoroughly cleaned. Refer to Preparation of Part or Area for NDI,