Tech Tip 2015-002
Aircraft Model: AS 350
Subject: Cabin Anti Vibrator Attach Bolts
Date: February 12, 2015
The cabin anti vibrators located under the cabin floor are attached to the airframe with six 6 millimeter bolts and washers. It is recommended to check the torque of the hardware at the 600 hour/T inspection or before adjusting the weights.
In the OPEN 350 and 355 AMM in 53-00-00-407, Removal/Installation, the text refers to the MTC, Standard Practices, when applying torque to the attaching hardware. The illustration does not show any value for torque on the hardware which indicates that you are to refer to Standard Practices for the correct procedure and value on that particular size of hardware. The standard torque value for the 6 millimeter bolt is 7.5-9 NM or 65-75 inch/pounds.
The same also applies in the ORION AMM for the 350B2/B3 in 53-32-00, 4-1.
However in the AMM section 53-00-00-501of the OPEN 350 and 355 as well as in the ORION AMM 53-32-00, 5-1, Adjustment of the cabin anti vibrators, the torque for the six attaching bolts is illustrated as 13-15 NM or 115-133 inch/pounds. Using this torque value has in a few cases resulted in the bolt shearing. The correct torque value to be used for the six attaching bolts is 7.5-9 NM or 65-75 inch/pounds.