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YO-233-B2A Engine Maintenance Manual
TEO-540-A1A Engine Maintenance Manual
72-70 - RECIPROCATING ENGINE – ELECTRICAL SYSTEM
1. General
The Electrical System includes the wiring harness.
A.
2. 100-Hour Wiring Inspection
A. Examine the airframe electrical wiring for correct routing, security, clamping, deterioration,
and chafing in accordance with the airframe manufacturer's instructions.
B. Record any worn or frayed airframe wiring. Replace worn or frayed wires.
C. Make sure the wiring connections are tight. Tighten any loose wiring connections.
D. Examine all of the wiring connections and accessories for physical damage and security.
E. If any wire is broken, chafed, worn or degraded on the wiring harness, the complete harness
must be replaced. Refer to the Direct Drive Overhaul Manual. Wiring degradation includes
the following:
(1) Degraded wire repairs or slices.
(2) Heat damaged or burn wire.
(3) Vibration damage or chafing.
(4) Cracked insulation.
(5) Arcing.
(6) Insulation delamination.
F. To replace damaged cables or clamps refer to the aircraft manufacturer's instructions.
G. Examine the terminals for correct installation, tightness, and cleanliness. Clean any dirty
terminal; tighten terminals as per the torque values in the latest revision of the Service Table
of Limits - SSP-1776.
3. Wiring Inspection
Look for damage on all wiring that can come in contact with chemicals and fluids such as:
A.
(1) Hydraulic fluid
(2) Battery electrolytes
(3) Fuel corrosion inhibiting compounds
(4) Waste system chemicals
(5) Cleaning agents
(6) Deicing fluids
(7) Paint
(8) Soft drinks.
Closely examine wiring that could have been exposed to hydraulic fluid during wiring
B.
inspection.
Look for heat damage on the wiring and on the engine in galleys, and behind lights.
C.
Though a visual inspection of the wiring harness can identify heat damage, burnt wire,
D.
vibration damage, or chafing, a more detailed inspection is necessary to identify cracked
insulation, arcing, insulation delamination, and degraded repairs or splices.
© 2021 Avco Corporation. All Rights Reserved
February 2021
72-70
Page 153
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