7.13 Control Cables Flashcards
What’s things get twisted to make control cables
Steel wires get twisted into strands and these are twisted into cables
Normally the wires are twisted in one direction and strands in the opposite
What are the number of wires and strands in one cable ratios
3/32 - 7x7
1/8 - 7x19
What does 7x19 mean
The first digit consist of 7 strands and the last figure tells you how many steels wires that are in the strand
What is the difference between 1x7, 7x7 and 7x19 cables
1x7 is non flexible
7x7 is flexible
With 7x19 being extra flexible
How should new cable be stored
Carefully to avoid kinking
Should be supplied on a wooden drum at least 40 times the diameter than the individual cable
How should cable be unwound
From a reel that is mounted to a spindle
What should you cut cable with
Cable cutters, heavy duty pliers, or anvil, hammer or chisel
After cutting cable what radii should they be coiled into
Radii of no less than 50 times the diameter of the wire
And never less then 150mm(6inch)
What should a cable not be cut with
Flame
What should you wear when you are checking for broken wires
Gloves
How should you examine a broken wires
Move a cloth along the cable in both directions
What are the permittable limits for 7x19 cable with broken wires
6 broken wires in a same one inch length of cable with no more than 3 broken wires for each strand
What are the permittable limits for a 7x7 cable with broken wires
3 broken wires in a same one inch length of cable with no more than 2 broken wires for each strand
For cables which touch pulleys or go through fairleads or pressure seals what is the rule regarding broken wires
No more than 3 broken wires is permittable
What else must a visual inspection of a cable look for
External wear of the cable, corrosion, internal cable wear
If a wire is worn over ……% it must be declared unserviceable
60%
When inspecting pulleys what must you look out for
Pulley wobble, cable does not skid in groove, incorrect wear at bottom of groove
What is the permitted amount of rolling sequences for sleeve terminals
No more than 4 rolling sequences
Will cause brittleness and hardening of material otherwise
What test must all connections between cable and terminal be subject too
Tensile strength test under a certain period of time
If there is a slippage between a cable and terminal then….?
The connection is not strong enough
Rolled on balls and terminals are checked for sufficient tensile strength by using a..?
Cable terminal pull tester
A cable is only allowed to be preloaded when it is not ……..?
Bent
How do you tighten a cable
By using a turnbuckle
When tightening cables what must you ensure for correct system rigging
Tightened evenly throughout
What does a cable tensiometer do
Precision instrument designed for rigging control cables
Before using a tensiometer you must ensure what?
The correct riser is mounted on the instrument for the cable size to be tested
When using a testiometer what must you do before you lock the break lever rod
Ensure the instrument is clamped on the cable else false reading
What are the three ways you can lock a turnbuckle
Wire locking
Lock nuts
Special locking clips
What’s are some advantages of cable and conduit
Lightweight and simple to install
What are the two most common methods of cable and conduit methods
Teleflex and bowden
(Consist of cable passing through conduit (covering) with correct end fittings)
What is the main advantage a cable system has over mechanical systems
Weight savings
What areas on a control cable are susceptible to wear and broken wires
Fairleads and pulleys
What technique is used to inspect internal wear in control cables
Move the strands apart to examine internally
What action much be taken when light surface corrosion is discover on a control cable
Re,over and re protect the cable again
What are the wear limits for a 80mm pulley
0.015” or 0.40mm max at top or groove
0.007” or 0.20mm at bottom of the groove
What are cables inspected in accordance with
AMM
What is used to check the correct swaying of terminal ends
Calliper gauge
How is slippage of end fittings indicated
By marking or painting the cable at the end fitting before carrying out the tension check
When rigging a control cable, extra tension will ……..
Damage pulleys and support structures
What is preloading
Necessary to preload as a new cables length would increase its length under load.
How is the left hand thread identified in a turnbuckle
By a groove on the left hand end
Before using a tensiometer what must be checked
Calibration sticker
Calibration table has same serial number as tensiometer
Check all rises are present
Lock mechanism works correctly
What are Bowden and teleflex cables designed to do in aircraft systems
Remotely operate services
Teleflex control cables are designed to transmit pulling loads only - True or false
False, they transmit pull and push forces. Bowden cable transmit force in one direction only
What is the difference between No2 and No380 cable (doubt we need to know)
No2 - built from High tensile steel which is wound with compression winding.
No380 - built from high tensile steel wire which is wound with a right hand helix winding and spacer winding
What are the conduits of Teleflex control cables normally manufactured from
Light alloy
(Sometimes steel and tungum for special circumstances)
(May be bent in curves to radii no less than 3 inches)
What are the devices used to secure straight sections of Teleflex cable conduit to structures
Clamp blocks 3 feet apart
Are no2 and no380 cables interchangeable
No, because of the difference in the lay of cables (left and right hand)
What are sliding end fitting used for
Used when necessary to convert pull- push movement of cable into rotary
What device is used to orevent Teleflex cables from turning in the conduit
Anti-torsion tube
A Bowden cable relies on what device for its return action
Springs
What is a junction box used for
To connect a single cable to two others
If a conduit is damaged what must you do
Renew it
Should bends on a conduit be small or big
As big as possible
