7.13 - Control Cables Flashcards
When using the Pacific T5 tensiometer, what 2 things should be noted?
Pacific T5 tensiometer. Correct chart and correct riser
What proof loading should the cable be subject to after swaging?
Proof loading after swaging. 50 to 60% of the cable max load
How would you check that a cable has been swaged correctly?
Swaging of a cable end fitting is checked by a Go/No-go gauge on the barrel
What is the smallest component of a control cable?
In a control cable, a wire is the smallest component of a control cable
How is linear to rotary motion in a control cable achieved?
Linear to rotary motion in a control cable run is achieved using Quadrants
What’s not acceptable over pulleys?
Broken wires over a pulley aren’t acceptable
What does 7x19 mean?
7x19
7 strands, 19 wires
When should a cable be replaced (% of wear)?
Cable should be replaced when individual wires are worn greater than 40%
Should you measure tension near pulleys or end fittings?
No, tension should be measured 6 inchs or more away from pulleys or fittings
Use correct chart and correct riser
Run a rag the full length of the cable
to have control surface locks into support weight and adjust turnbuckles equally
50% minimum breaking strain
use a go/no-go gauge on the barrel
the basic smallest component of a control cable
Remain in service
7x7 -Replace if 2 broken wires in a one-foot length of a 7x7 cable. Max of 3 broken within its full length between end fittings. Note: Cable must be replaced if a single wire is broken due to corrosion or rust or where it passes over a fairlead
7x19 - Replace the cable if 4 wires broken within a 12 inch section OR more than 6 broken wires between end fittings OR if a single wire is broken due to corrosion
Note: Broken wires are NOT PERMITTED at bends/over pulleys/pressure seals or fairleads
Quadrants
Quadrants and Bell Cranks are used to convert Linear to Rotary motion & vice versa
50%-60% of the cable max load
When swaging is complete confirm correct plastic deformation of the end fitting by means of a micrometre or Go/No Go gauge & PROOF LOADING TEST. 50% OF MAX CABLE STRENGTH PER BRITISH SPEC & 60% PER US SPEC.
Note: Proof loading the entire cable run Pre Stretches the cable
3 for any cable diameter
'’Check turnbuckles, max 3 threads visible & locking clips or lock wire installed - Secondary cable stops are at the controls on the flight deck rigged with a small clearance’’
Is not acceptable
Cable must be replaced if a single wire is broken due to corrosion or rust or WHERE IT PASSES OVER A FAIRLEAD
Broken wires are NOT PERMITTED at bends/over pulleys/pressure seals or fairleads
7 strands of 19 wires
40%
Cable wear: replace cables if wires are worn beyond 40% of original cross section
the end fittings on the cable are secure
'’When the swaging is complete confirm correct plastic deformation of the end fitting by means of a micrometre or Go/No Go gauge & PROOF LOADING TEST. 50% OF MAX CABLE STRENGTH PER BRITISH SPEC & 60% PER US SPEC
Proof loading the entire cable run Pre stretches the cable
Option B: not required
Proof testing after cable installation is not required, however it is required after swaging an end of the cable to ensure end fitting is secure. i.e 50 - 60% of maximum cable strength
Option B: rejected
Option C: enable the cable to be tensioned
Option A: Use correct chart and correct riser
Option B: Equalizes control cable tension
Option C: Run a rag the full length of the cable
Option C: using a chisel on a flat metal surface
Option B: looking for a shiny surface on the cable near the fitting
Option C: at least 40 times that of the cable diameter
Option C: A tube is fitted over the turnbuckle assembly and drilled to take up to 3 bolts, to prevent rotation of any part
Option C: to have control surface locks in to support weight and adjust turnbuckles equally
Option C: if a chemical spillage is suspected
Option C: 50% of minimum breaking strain
Option A: run a rag along the cable in both directions
Option C: the aircraft will be heavy on controls
Option A: the end fittings on the cable are secure
Option B: attempting to pass a hardened pin probe through the inspection hole
Option B: replace the cable
Option A: Galvanising
Option A: To ensure the cable end passes the inspection hole on drilled through type fittings but leaves the locking wire hole clear
Option C: to ensure that the turnbuckle is in safety
Option B: using a go/no-go gauge on the barrel
Option A: single wires are blended together
Option B: it will prevent the control surface and the control column movement
Option B: full and free movement
Option A: 40%
What is the criteria for allowable broken wires in a 7x7 and a 7x19?
7x7
Replace if 2 broken wires in a one-foot length
Max of 3 broken wires in its full length
**7x19 **
Replace if 4 broken wires in a one-foot length
Max of 6 broken wires in its full length
Broken wires are NOT PERMITTED at bends/over pulleys/pressure seals or fairleads and any single wire broken due to corrosion, whole cable must be rejected.
Middle of a control run
is strong and light
broken
Note: Trick question, says worn TO 40%, cable must be replaced if individual wire is worn GREATER than 40%
Dipping the cable end in lanolin to fit
both ends simultaneously
Teleflex control
1/ The inspection hole is covered or only the required number of threads is shown (max 3)
3/ Locking clip or wire
'’Check turnbuckles, max 3 threads visible & LOCKING CLIPS or Lock Wire installed’’
3/ A single steel extrusion
1/ Swaged
3/ It will transmit both tensile and compressive loads
'’Teleflex Helix Cables; Similar to Bowden cable but has a CORE TENSION CABLE SURROUNDED BY MAN LH or RH SPIRALLY WOUND CABLES / it is better able to transmit push / pull movement due to its greater strength NOTE; Follow AMM procedure for removing, inspecting & lubricating inner cable. TRANSMITS BOTH TENSILE & COMPRESSIVE LOADS
Bowden & Teleflex are ‘‘Flexible Cables’’
3/ Convert linear to rotary and vice versa
'’Quadrants & Bell Cranks are used to convert LINEAR TO ROTARY MOTION & VICE VERSA’’
3/ A weight that pulls the cable in the return direction
'’Bowden Cables = A flexible inner cable operating within a hollow outer cover (similar to a bicycle break cable) / used as a pull cable (most common) or as a push/pull cable / eg CESSNA throttle cable. Advantage is its ability to bend, dis-advantage is BACKLASH, making it unsuitable for a large force over a long distance. NOTE: IT USES A WEIGHT TO RETURN CABLE’’
2/ Another cable in the control set (balance cable)
(answer needs to be verified)
a) a cable tension regulator
'’A Tension Regulator is used to maintain correct tension despite fuselage flex and temperature changes’’
B. have ontrol surface locks in to support weight and adjust turnbuckles equally
'’Cable Tension Check = First confirm cable diameter / Use Tensiometer / adjust turnbuckles / check Rigging Pins. Check that tensiometer & its chart are valid / check temperature of the day V cable load / check correct RISER is fitted. Take several readings along Straight Cable Runs
Note: it is easier to take readings if the flight control surfaces are supported’’
B. Overall diameter
A. 9 strands of 16 wires
'’7 X 19 = 7 strands made up of 19 wires’’
Note; There are TWO cables in every control loop, one carrying the motion and the second called a BALANCE CABLE’’
C. adjust minor tensions on the cable on set-up
C. the cable is misaligned
'’Pulley inspection - made from Tufnol or Micarta for roughness, unusual wear, wobble, flat spots, interference with structure. Eg Wear to one side of pulley indicates MIS-ALIGNED CABLE’’
C. At the controls in the cockpit
'’Secondary Cable stops are at the controls on the flight deck rigged with a small clearance’’
A/ a small gap
'’Secondary Cable stops are at the controls on the flight deck rigged with a small clearance’’
B. a high tensile steel wire with a right or left hand helix wire wound on to it in a conduit tube. The system can operate in two directions.
'’Teleflex Helix Cables; Similar to Bowden cable but has a CORE TENSION CABLE surrounded by MANY LH or RH SPIRALLY WOUND CABLES / it is better able to transmit push / pull movement due to its greater strength NOTE; Follow AMM procedure for removing, inspecting & lubricating inner cable. TRANSMITS BOTH TENSILE & COMPRESSIVE LOADS
Bowden & Teleflex are ‘‘Flexible Cables’’
B. maintain the necessary tension
'’A Tension Regulator is used to maintain correct tension despite fuselage flex and temperature changes’’
C. Pulleys
'’Pulleys are used to change cable direction’’
A. Single wires are blended together
c/ to check the end fitting swage and to pre-stretch the cable
'’When the swaging is complete confirm correct plastic deformation of the end fitting by means of a micrometre or Go/No Go gauge & PROOF LOADING TEST. 50% of max cable strength per british spec and 60% per US spec. Note; Proof loading the entire cable run Pre Stretches the cable’’
a/ four wires are broken in a 12 inch length
Replace cables if:
7x7 2 broken wires in one-foot length - Max 3 full length between end fittings
7x19 4 broken wires in one-foot length - max 6 full length between end fittings
Cable must be replaced if a single wire is broken due to corrosion or rust or where it passes over a fairlead
b/ it is replaced
'’Cable must be replaced if a single wire is broken due to corrosion or rust or where it passes over a fairlead’’
b/ it is replaced
'’Cable must be replaced if a single wire is broken due to corrosion or rust or where it passes over a fairlead’’
a/ 50/ 60% of the breaking load
'’When the swaging is complete confirm correct plastic deformation of the end fitting by means of a micrometre or Go/No Go gauge & PROOF LOADING TEST. 50% of max cable strength per British spec & 60% per US spec. Note; Proof loading the entire cable run Pre stretches the cable’’
a/ bigger than the final diameter
c/ operate and check full free and correct
'’Ensure cables havve Full Free & Correct Movement’’
b/ bowden and teleflex
'’Bowden & Teleflex are ‘Flexible Cables’’’
b/ use a dry clean cloth to pick out broken wires
'’DO NOT use solvents to clean cables, it removes lubricant, use a clean dry cloth. Apply correct grease to Carbon Steel with a cloth after inspection. Note; Do not lubricate CRS cables’’
b/ it is checked in usual way but at an area without the cladding
'’LOCKCLAD CABLES have a swaged AL ALLOY tube swaged onto it to help reduce temperature effects, check tension standard way (cable diameter/use tensiometer -correct riser/adjust turnbuckles etc) but not on the cladded portion.’’
b/ too many passes of the swager dies were made during manufacture
'’Cracks on end fitting indicate too many blows resulting in work hardening cracking’’
b/ more than the breaking strength of the cable
'’The grip of a correctly fitted terminal will be greater than the breaking strength of the cable’’
b/ 3
'’Check turnbuckles, max 3 threads visible & LOCKING CLIPS or LOCKWIRE installed ‘’
