CASA Part 66: Nicopress Process for Copper Sleeves

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Questions and Answers

What is the primary purpose of using a Nicopress crimping tool?

To attach a thimble to the cable

To reduce the diameter of the sleeve and form a strong bond (correct)

To strip the insulation from the cable

To cut the cable to a specific length

What is the correct order of compression when using a Nicopress sleeve?

Nearest the thimble, then centre, then end of the sleeve

Centre compression, then nearest the thimble, then end of the sleeve (correct)

End of the sleeve, then centre, then nearest the thimble

End of the sleeve, then nearest the thimble, then centre

What is the purpose of applying a band of paint to the cable and sleeve?

To identify the type of cable used

To indicate if the cable has slipped during inspection (correct)

To provide additional grip to the sleeve

To mark the cable for future maintenance

What is the minimum percentage of cable strength achieved by a Nicopress termination?

100% Signup and view all the answers

How many Nicopress sleeves are used to join two lengths of cable?

Two Signup and view all the answers

What is the purpose of the Nicopress gauge?

To check the compressions after installation Signup and view all the answers

What is the purpose of applying a ring of brightly coloured paint around the end of the terminal and cable?

To indicate any subsequent slippage Signup and view all the answers

What is the purpose of the Proof-Load Test after the cable is completed with the terminals?

To load the cable to 60% of its breaking strength Signup and view all the answers

Where are cables most likely to wear or break?

When passing over pulleys or through fairleads Signup and view all the answers

What is the primary method of inspecting cables for broken wires or strands?

Wiping the cable with a clean, dry rag Signup and view all the answers

What should be done to inspect for corrosion in a cable?

Disconnect the cable and bend it into a loop Signup and view all the answers

How often should cables be inspected?

At each scheduled inspection Signup and view all the answers

What should you avoid doing when bending the cable during inspection?

Twisting it opposite its natural lay orientation Signup and view all the answers

What is a critical fatigue area in aircraft control cable inspection?

The area where the cable runs over, under or around a pulley, sleeve or fairlead Signup and view all the answers

Why is it necessary to use a cloth to inspect the cable?

To detect broken wires Signup and view all the answers

What may indicate the presence of a broken wire in the cable?

A hairline crack in the wire Signup and view all the answers

What is recommended to further inspect a suspected broken wire?

Using a powerful flashlight and a 7-power magnifying glass or greater Signup and view all the answers

What publication recommends a procedure for inspecting aircraft control cables?

FAA publication, AC 43.13–1B Signup and view all the answers

What is the recommended action for a cable assembly with a broken wire strand in a critical area?

Replace the entire cable assembly Signup and view all the answers

Why is it important to wipe corrosion-resistant stainless steel cables with LPS-3, Boeshield T-9, or Dinitrol ML?

To prevent corrosion and lubricate the cables Signup and view all the answers

What is indicated by external wear patterns on a cable?

The cable has moved a certain distance at that location Signup and view all the answers

When should flexible and non-flexible cables be replaced?

When the individual wires in each strand blend together Signup and view all the answers

What occurs internally in a cable as wear takes place on the exterior surface?

The same wear condition occurs internally Signup and view all the answers

What causes the type of wear that occurs internally in a cable?

The relative motion between inner wire surfaces Signup and view all the answers

What is the primary purpose of using rig pins in aircraft control systems?

To lock the control surfaces and major quadrants in place Signup and view all the answers

What is the tool used to check the tension of control cables?

Cable tensiometer Signup and view all the answers

What is the purpose of a cable tension compensator assembly?

To compensate for expansion and contraction of the airframe Signup and view all the answers

What is the reading on the cable tensiometer scale?

An arbitrary reading for the particular riser Signup and view all the answers

How are the risers on a cable tensiometer used?

To correspond to the cable diameter Signup and view all the answers

What is the purpose of the pointer lock on a cable tensiometer?

To lock the reading on the scale Signup and view all the answers

Study Notes

Nicopress Process

Nicopress sleeves are compressed into a cable using a special crimping tool, reducing the sleeve diameter and forming an extremely strong bond.
The cable is passed through the sleeve and around the thimble, with about 1/8 in. visible beyond the sleeve.
Three compressions are made: centre compression, then compression nearest the thimble, and finally compression at the end of the sleeve.
A Nicopress termination produces 100% of the cable strength.

Nicopress Gauge and Splice

Compressions are checked with a special Nicopress gauge, which ensures the sleeve fits snugly in the slot.
Running splices can be made to join two lengths of cable using two Nicopress sleeves.
When two sleeves are used correctly, the splice is approved as having the full cable strength.

Safety Feature and Testing

A band of paint is applied to the cable and sleeve to assist during inspection; if broken, it indicates the cable has slipped and further inspection is required.
A spot of paint is applied to the cable against the sleeve, and a ring of brightly coloured paint is applied around the end of the terminal and cable after testing.
The cable is tested by loading it to 60% of its breaking strength, with the load applied gradually and held for at least 3 min.

Cable Inspection Practices

Cables are carefully examined at each scheduled inspection, especially where they pass over pulleys or through fairleads.
Wear and corrosion are the two most common problems with control cables.
Inspect for broken wires or strands by wiping a clean, dry rag over the cable, and move the controls through their full range to check for wear.
Check for corrosion by disconnecting the cable, bending it into a loop, and using a torch and magnifying glass to inspect.

Cable Wear and Corrosion

Critical fatigue areas are defined as the working length of a cable where it runs over, under, or around a pulley, sleeve, or fairlead, or where it is flexed, rubbed, or worked in any manner.
Close inspection of these areas must be made by passing cloth over the areas to snag on broken wires.
Visual inspection must be made to detect broken wires, which may show up as a hairline crack in the wire.
Cables with one broken wire strand located in a critical area must be replaced.

Corrosion Prevention

Corrosion-resistant stainless steel cable is used in seaplanes and agricultural aircraft, which operate in environments conducive to corrosion.
It is recommended to wipe these cables with LPS-3, Boeshield T-9, or Dinitrol ML to protect and lubricate the cables.

Cable Tension

Cable tension is checked with a cable tensiometer, which must be placed in a clear area of each section of cable, midway from any quadrants, bell cranks, or surfaces.
The tensiometer reading is converted to tension in pounds using a chart.
Most large transport aircraft are fitted with a cable tension compensator assembly, which compensates for expansion and contraction of the airframe and regulates control cable tension accordingly.

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Description

Learn about the Nicopress process for copper sleeves in aviation maintenance. Understand how to compress Nicopress sleeves onto a cable using a special crimping tool and create a strong bond.