Presentation on theme: "Follow in your AIRCRAFT INSPECTION, REPAIR & ALTERATIONS MANUAL – PAGE 7-27."— Presentation transcript:
Follow in your AIRCRAFT INSPECTION, REPAIR & ALTERATIONS MANUAL – PAGE 7-27
Cables and there function
Cables are mostly used to control engine and flight controls through their normal range of movement
Cables are made of high carbon steel or corrosion resistant steel wire
A flexible cable is generally made up of a number of strands or group of strands of wire. When a group of stands is used they are woven around the centre strand or core to complete the cable. A flexible cable that is a 7 by 7 would be 6 cables wrapped around a centre cable (or core). Each of these 7 cables would be made up of 7 smaller cables in same way (6 around 1).
Non -flexible cables have no centre cable so they would be described as a 1 by 19, which is 19 wires in a bundle A nylon cable is coated with nylon and resists breaking down. It generally has a longer service life
Most cable wear occurs where the cable bends (pulley and is caused by friction between the strands. When dealing with an unprotected cable this can be aggravated by a dirt or grit. On long straight cable runs constant vibration can work harden the cable and cause it to become brittle and fray.
Replace the cables if they become distorted, worn, or corroded.. If you can not replace the cable then an approved repair can take place until a replacement part can be installed. No splice comes closer than 2 inches to a pulley or fairlead. SHOW ON THE BOARD HOW WHEN MAKING A REPAIR THE REPAIR CAN NOT INTERFERE WITH THE CABLE RUN.
Always use the proper tools and manuals when attempting a swag repair. Measurement of the swagged fitting can be done with a no -go gauge or a micrometer. The finished swag fitting must meet manual standards (see page 7- 31) and not be out of round. Check the proof load of the finished product by applying 60 percent of the total allowable load. TALK ABOUT NICO PRESS AND THE WAY IT IS USED
Use the charts on pg 7-34 to determine the size of thimble to use. When making a eye splice (pg 7-33) always make sure the cable extends beyond the thimble as the thimble will elongate. When using a lap splice two thimbles are used to give adequate strength to the cable run
Cable inspection should be done when ever required by the appropriate manuals. Check the cable for frays, broken strands, corrosion, or other signs of wear. Give special attention to areas where the cable turns or bends as this is a high stress area.
Using a rag or cotton gloves while checking for frays will save you hands from getting metal splinters. In some instances a broken wire may not be sticking out of the cable and may only appear as a hairline crack on the cable. At this point you can use a magnifying glass and also bend or twist the cable to see if the frayed wire pops out. See pg 7-37 figure 7-19 for a view of a cable that may have breaking down internally from fatigue.
Always inspect the cable through its full travel. Have someone move the cable from the cockpit as you are inspecting it, pay special attention to problem areas like pulleys, areas near washrooms and battery compartments
Check pulleys for excessive wear, flat spots or dirt. Make sure it moves freely and the bearing has proper lubrication.The pulley must also be aligned to prevent the cable from riding on the flanges. Some times a dry mollycoat spray is the best to use as it doesnt attract dirt. See chart 7-20 on pg 7-38 for examples.
Check any wire splices if they exist for defects. Ensure the wire appears to be positioned properly in the splice
Part of the inspection with cables includes that they are properly tensioned. Use the appropriate manuals to check the tension on each cable run. When taking tensions ensure the cables are at room temp