Exam Question

(a) Reasons for Persistent Slackening of Main Engine Holding Down Bolts
The persistent slackening of a main engine's holding-down bolts is a serious issue that can compromise the engine's alignment and structural integrity. The primary reasons for this problem are:
Vibration and Dynamic Forces: The engine's continuous operation creates powerful vibrations and dynamic forces from combustion and reciprocating parts. These forces repeatedly stress the bolts, causing them to gradually lose tension over time.
Insufficient Tightening: If the bolts were not tightened to the manufacturer's specified torque during installation or maintenance, they lack the necessary pre-tension to resist operational forces, leading to faster slackening.