Textron Bell 412, Maintenance Manual

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BHT-412-MM-2
5-00-00
30 AUG 2013 Rev. 19 Page 223 Export Classification C, ECCN EAR99
b. Inspect main rotor blades and control links,
transmission system, driveshafts, gearboxes, and tailboom
structure for magnetization. Using a magnetometer with a
range no larger than

5 gauss, place arrow or red dot
(depending on magnetometer model) within 0.5 inch
(12.70 mm) of item being checked with arrow pointing directly
at item. If components of any item have a reading greater than
one gauss, those items shall be degaussed.
NOTE
Do not test chip detectors for magnetization. If
transmission or gearbox magnetic readings are
greater than one gauss near chip detector, remove
chip detector from housing and repeat test.
c. Remove and bench test DC control units. Operationally
check starter generators and inverters for proper operation.
Visually inspect starter generators and inverters for burns or
electrical arcing. If damaged, remove for internal inspection
and bench test.
d. Perform operational check of bussing system as
dictated in the BHT-412-MM.
e. Inspect transmission and tail rotor gearbox chip
detectors for proper operation. Remove chip detectors found
inoperative.
f. Perform operational check of interior and exterior
lighting system. Replace lamps, bulbs, and lighting assemblies
as required.
g. Perform operational check on all instruments. Remove
and repair/replace instruments and sensors found to be
defective.
Chapter 96 h. Perform operational check on all caution messages for
proper operation.
6. When it has been established lightning has struck
helicopter, the structural inspections that follow are mandatory
to ensure safety of flight:
CONDITIONAL INSPECTIONS
5-42. AFTER LIGHTNING STRIKES (CONT)
DATA REFERENCE INSPECTION TASK DESCRIPTION
INITIAL
MECH OTHER