TM 1-1520-264-23
2.2
MAIN ROTOR DROOP STOP FOLLOWER (PLUNGER) (PT).
2.2.1
Description (Figure 2-1. Index No. 2). The main rotor droop stop follower (plunger) contacts the droop stop ring
to limit the pitch housing downward movement when the main rotor blade assembly is stopped.
2.2.2
Defects. This inspection is used to verify crack indications found visually on the main rotor droop stop follower
(plunger). No cracks are allowed.
2.2.3
Primary Method. Fluorescent Penetrant.
2.2.3.1 NDI Equipment and Materials. (Refer to Appendix B.) Inspection equipment is listed in Table 1-7. MIL-1-25135
level 3 penetrant materials shall be selected from the approved list in Table 1-8.
2.2.3.2 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 main rotor droop stop follower (plunger) shall be removed in
accordance with the applicable technical manuals listed in Table 1-1.
2.2.3.3 Access. Not applicable.
2.2.3.4 Preparation of Part. Refer to Preparation of Part or Area for NDI, paragraph 1.4.4.
2.2.3.5 Inspection Procedure. Perform fluorescent penetrant inspection. Refer to Fluorescent Penetrant Method,
paragraph 1.4.7 and Table 1-5. Inspect area of concern. See Figure 2-2.
2.2.3.6 Marking and Recording of Inspection Results. Mark and record the inspection results as required by paragraph
1.3.
2.2.4
Backup Method. None required.
2.2.5
System Securing. Clean the main rotor droop stop follower (plunger) to remove inspection media. Refer to Post
Cleaning and Restoration of Part or Area After NDI, paragraph 1.4.16. The main rotor droop stop follower (plunger), if
removed, requires installation in accordance with the applicable technical manuals listed in Table 1-1.
2.3
DROOP STOP RING (MT).
2.3.1
Description (Figure 2-1. Index No. 3). The main rotor droop stop ring provides the contact surface for the droop
stop follower to limit downward movement when the main rotor blade assembly is stopped.
2.3.2
Defects. This inspection is used to verify crack indications found visually on the main rotor droop stop ring. No
cracks are allowed.
2.3.3
Primary Method. Magnetic Particle.
2-5
