BRISTELL BRMAERO Bristell B23, Руководство по обслуживанию

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Bristell B23 Airplane Maintenance Manual
Chapter 20
Issue: 30-Sep-2020 Chapter 20 Page 3
20-10 Bolt Joints
20-10-01 Torque Moments
Unless otherwise prescribed, the torque moments shown in the
following table can be used. When tightening follow several rules:
▶ Unless specifically stated do not grease neither nut nor
bolt.
▶ If possible, always tighten the nut. If for some space
reasons it is necessary to tighten the bolt head and the
scope of tightening moment is defined. Use higher
moment for tightening.
▶ Maximum moments are used only for the materials and
surfaces, which have a sufficient thickness, area and
strength resistant to bursting, warping or other damage.
Maximum tightening moments must not be exceeded.
Bolt size
Torque limits recommended Max. allowable torque limits
Nm in lb Nm in lb
AN3 2.3 - 2.8 20 - 25 4.5 40
AN4 5.7 - 7.9 50 - 70 11.3 100
AN5 11.3 - 15.8 100 - 140 25.4 225
AN6 18.1 - 21.5 160 - 190 44.1 390
AN7 50.9 - 56.5 450 - 500 94.9 840
AN8 54.2 - 78 480 - 690 124.3 1100
AN9 90.4 - 113 800 - 1000 180.8 1600
Tab. 1 Recommended Torque Values for Oil-free, Cadmium-plated Threads
20-10-02 Orientation of Bolts and Cotter Pins
Put the bolts to the joint on the basis of “top - down” rule or “From the
front to the back" with regard to the flight direction. This rule
decreases possibility of spontaneous bolt falling out of the clamp
joint in case that nut unlocking and falling out occurs in the course of
operation. Follow the same rule also in case of securing nuts by
securing pins or by cotter pins, with the exception of those cases
when it is not possible to install the bolt for design or operation
limitation reasons.