Adjust, align and calibrate

Flap Restraint Assembly

To adjust the flap restraint assembly to a serviceable condition, do the following:

  1. Make sure that the arm assemblies move freely and that the springs retract the arm assemblies to their full vertical positions.

  2. Start the engine. While the RPM of the main rotor (NR) increases, record the RPM percentage (NR) at which the arm assemblies extend. Complete the start of the engine and let the oil temperature and the oil pressure become stable. Stop the engine. While the RPM of the main rotor (NR) decreases, record the RPM percentage (NR) at which the arm assemblies retract to their full vertical positions.

  3. Make sure that the arm assemblies extend or retract between an RPM of 25 and 31%.

  4. If the arm assemblies do not extend correctly or retract between an RPM of 25 and 31%, do as follows:

    1. Make sure that the total quantity of washers installed is always the same.

    2. Make sure to replace a maximum of four washers on each arm assembly.

  5. Increase the weight of the arm assemblies by replacing a small washer with a large washer in the conditions that follow:

    1. If the arm assemblies do not fully extend while the RPM is more than 31%.

    2. If the arm assemblies fully retract while the RPM is more than 31%.

  6. Decrease the weight of the arm assemblies by replacing a large washer with a small washer in the conditions that follow:

    1. If the arm assemblies extend while the RPM is less than 25%.

    2. If the arm assemblies do not fully retract while the RPM is less than 25%.

  7. Apply Corrosion preventive compound to the nuts.

  8. A maximum of two washers can be removed on each eyebolt. This changes the tension of the springs and lets you adjust the retract and extend of the arm assemblies.

  9. If it is not possible to adjust the arm assemblies to extend and retract at the correct main rotor RPM with the adjustment of the washers, do the steps that follow:

  10. Measure the springs with a Spring scale for a rate of 0.84 ±0.08 pound (3.7 ±0.35 Nm) for an extension of 1 inch.

  11. Replace any spring that does not have the correct rate.

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