TM 1-1520-253-23
6.5 THRUST CONTROL BELLCRANK AND SUPPORT (ET).
6.5.1 Description (Figure 6-1. Index No. 5). The pilot and copilot each have a set of controls. They are interconnected
under the cockpit floor so that if one set is moved, the other set moves in the same direction. Each set of controls
contains a pitch and roll control stick, a thrust control, and yaw pedals.
6.5.2 Defects. Inspect for damage after removal of bent or sheared rigging pin. No cracks are allowed.
6.5.3 Primary Method. Eddy Current.
a. Eddy Current Inspection Unit
b. Probe, straight, shielded surface, 100 KHz-500 KHz
c. Probe, right angle, shielded surface, 100 KHz-500 KHz, 901/2 inch drop
d. Cable Assembly
e. Reference Block, three-notched aluminum (0.008, 0.020, and 0.040 EDM notches)
g. Aircraft Marking Pencil, refer to Table 1-8
6.5.3.2 Preparation of Helicopter. The helicopter shall be prepared for safe ground maintenance. 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 bellcrank shall be removed in accordance with the applicable
6.5.3.3 Access. Access through the cockpit or the landing light openings as necessary to inspect the support.
6.5.3.4 Preparation of Part. The bellcrank and support shall be thoroughly cleaned. Refer to Preparation of Part or Area
6.5.3.5 NDI Equipment Settings.
II
a. Make the following initial settings on the Eddy Current Inspection Unit, NORTEC-19e .
- 200 KHz
F2
- off
HdB
- 57.0
VdB
- 69.0
Rot
- 56
Probe drive
- mid
LPF
- 100
HPF
-0
H Pos
- 80%
V Pos
- 20%
6-9